30 results on '"Abdessamad Tahiri-Alaoui"'
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2. Poly(A) binding protein 1 enhances cap-independent translation initiation of neurovirulence factor from avian herpesvirus.
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Abdessamad Tahiri-Alaoui, Yuguang Zhao, Yashar Sadigh, James Popplestone, Lydia Kgosana, Lorraine P Smith, and Venugopal Nair
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Medicine ,Science - Abstract
Poly(A) binding protein 1 (PABP1) plays a central role in mRNA translation and stability and is a target by many viruses in diverse manners. We report a novel viral translational control strategy involving the recruitment of PABP1 to the 5' leader internal ribosome entry site (5L IRES) of an immediate-early (IE) bicistronic mRNA that encodes the neurovirulence protein (pp14) from the avian herpesvirus Marek's disease virus serotype 1 (MDV1). We provide evidence for the interaction between an internal poly(A) sequence within the 5L IRES and PABP1 which may occur concomitantly with the recruitment of PABP1 to the poly(A) tail. RNA interference and reverse genetic mutagenesis results show that a subset of virally encoded-microRNAs (miRNAs) targets the inhibitor of PABP1, known as paip2, and therefore plays an indirect role in PABP1 recruitment strategy by increasing the available pool of active PABP1. We propose a model that may offer a mechanistic explanation for the cap-independent enhancement of the activity of the 5L IRES by recruitment of a bona fide initiation protein to the 5' end of the message and that is, from the affinity binding data, still compatible with the formation of 'closed loop' structure of mRNA.
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- 2014
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3. Heterologous amyloid seeding: revisiting the role of acetylcholinesterase in Alzheimer's disease.
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Létitia Jean, Benjamin Thomas, Abdessamad Tahiri-Alaoui, Michael Shaw, and David J Vaux
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Medicine ,Science - Abstract
Neurodegenerative diseases associated with abnormal protein folding and ordered aggregation require an initial trigger which may be infectious, inherited, post-inflammatory or idiopathic. Proteolytic cleavage to generate vulnerable precursors, such as amyloid-beta peptide (Abeta) production via beta and gamma secretases in Alzheimer's Disease (AD), is one such trigger, but the proteolytic removal of these fragments is also aetiologically important. The levels of Abeta in the central nervous system are regulated by several catabolic proteases, including insulysin (IDE) and neprilysin (NEP). The known association of human acetylcholinesterase (hAChE) with pathological aggregates in AD together with its ability to increase Abeta fibrilization prompted us to search for proteolytic triggers that could enhance this process. The hAChE C-terminal domain (T40, AChE(575-614)) is an exposed amphiphilic alpha-helix involved in enzyme oligomerisation, but it also contains a conformational switch region (CSR) with high propensity for conversion to non-native (hidden) beta-strand, a property associated with amyloidogenicity. A synthetic peptide (AChE(586-599)) encompassing the CSR region shares homology with Abeta and forms beta-sheet amyloid fibrils. We investigated the influence of IDE and NEP proteolysis on the formation and degradation of relevant hAChE beta-sheet species. By combining reverse-phase HPLC and mass spectrometry, we established that the enzyme digestion profiles on T40 versus AChE(586-599), or versus Abeta, differed. Moreover, IDE digestion of T40 triggered the conformational switch from alpha- to beta-structures, resulting in surfactant CSR species that self-assembled into amyloid fibril precursors (oligomers). Crucially, these CSR species significantly increased Abeta fibril formation both by seeding the energetically unfavorable formation of amyloid nuclei and by enhancing the rate of amyloid elongation. Hence, these results may offer an explanation for observations that implicate hAChE in the extent of Abeta deposition in the brain. Furthermore, this process of heterologous amyloid seeding by a proteolytic fragment from another protein may represent a previously underestimated pathological trigger, implying that the abundance of the major amyloidogenic species (Abeta in AD, for example) may not be the only important factor in neurodegeneration.
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- 2007
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4. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK
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Merryn Voysey, Sue Ann Costa Clemens, Shabir A Madhi, Lily Y Weckx, Pedro M Folegatti, Parvinder K Aley, Brian Angus, Vicky L Baillie, Shaun L Barnabas, Qasim E Bhorat, Sagida Bibi, Carmen Briner, Paola Cicconi, Andrea M Collins, Rachel Colin-Jones, Clare L Cutland, Thomas C Darton, Keertan Dheda, Christopher J A Duncan, Katherine R W Emary, Katie J Ewer, Lee Fairlie, Saul N Faust, Shuo Feng, Daniela M Ferreira, Adam Finn, Anna L Goodman, Catherine M Green, Christopher A Green, Paul T Heath, Catherine Hill, Helen Hill, Ian Hirsch, Susanne H C Hodgson, Alane Izu, Susan Jackson, Daniel Jenkin, Carina C D Joe, Simon Kerridge, Anthonet Koen, Gaurav Kwatra, Rajeka Lazarus, Alison M Lawrie, Alice Lelliott, Vincenzo Libri, Patrick J Lillie, Raburn Mallory, Ana V A Mendes, Eveline P Milan, Angela M Minassian, Alastair McGregor, Hazel Morrison, Yama F Mujadidi, Anusha Nana, Peter J O’Reilly, Sherman D Padayachee, Ana Pittella, Emma Plested, Katrina M Pollock, Maheshi N Ramasamy, Sarah Rhead, Alexandre V Schwarzbold, Nisha Singh, Andrew Smith, Rinn Song, Matthew D Snape, Eduardo Sprinz, Rebecca K Sutherland, Richard Tarrant, Emma C Thomson, M Estée Török, Mark Toshner, David P J Turner, Johan Vekemans, Tonya L Villafana, Marion E E Watson, Christopher J Williams, Alexander D Douglas, Adrian V S Hill, Teresa Lambe, Sarah C Gilbert, Andrew J Pollard, Marites Aban, Fatola Abayomi, Kushala Abeyskera, Jeremy Aboagye, Matthew Adam, Kirsty Adams, James Adamson, Yemi A. Adelaja, Gbadebo Adewetan, Syed Adlou, Khatija Ahmed, Yasmeen Akhalwaya, Saajida Akhalwaya, Andrew Alcock, Aabidah Ali, Elizabeth R. Allen, Lauren Allen, Thamires C. D. S. C Almeida, Mariana P.S. Alves, Fabio Amorim, Foteini Andritsou, Rachel Anslow, Matthew Appleby, Edward H. Arbe-Barnes, Mark P. Ariaans, Beatriz Arns, Laiana Arruda, Paula Azi, Lorena Azi, Gavin Babbage, Catherine Bailey, Kenneth F. Baker, Megan Baker, Natalie Baker, Philip Baker, Lisa Baldwin, Ioana Baleanu, Danieli Bandeira, Anna Bara, Marcella A.S. Barbosa, Debbie Barker, Gavin D. Barlow, Eleanor Barnes, Andrew S. Barr, Jordan R. Barrett, Jessica Barrett, Louise Bates, Alexander Batten, Kirsten Beadon, Emily Beales, Rebecca Beckley, Sandra Belij-Rammerstorfer, Jonathan Bell, Duncan Bellamy, Nancy Bellei, Sue Belton, Adam Berg, Laura Bermejo, Eleanor Berrie, Lisa Berry, Daniella Berzenyi, Amy Beveridge, Kevin R. Bewley, Helen Bexhell, Sutika Bhikha, Asad E. Bhorat, Zaheda E. Bhorat, Else Bijker, Geeta Birch, Sarah Birch, Adam Bird, Olivia Bird, Karen Bisnauthsing, Mustapha Bittaye, Katherine Blackstone, Luke Blackwell, Heather Bletchly, Caitlin L. Blundell, Susannah R. Blundell, Pritesh Bodalia, Bruno C. Boettger, Emma Bolam, Elena Boland, Daan Bormans, Nicola Borthwick, Francesca Bowring, Amy Boyd, Penny Bradley, Tanja Brenner, Phillip Brown, Claire Brown, Charlie Brown-O'Sullivan, Scott Bruce, Emily Brunt, Ruaridh Buchan, William Budd, Yusuf A. Bulbulia, Melanie Bull, Jamie Burbage, Hassan Burhan, Aileen Burn, Karen R. Buttigieg, Nicholas Byard, Ingrid Cabera Puig, Gloria Calderon, Anna Calvert, Susana Camara, Michelangelo Cao, Federica Cappuccini, João R. Cardoso, Melanie Carr, Miles W. Carroll, Andrew Carson-Stevens, Yasmin de M. Carvalho, José A.M. Carvalho, Helen R. Casey, Paul Cashen, Thais Castro, Lucia Carratala Castro, Katrina Cathie, Ana Cavey, José Cerbino-Neto, Jim Chadwick, David Chapman, Sue Charlton, Irina Chelysheva, Oliver Chester, Sunder Chita, Jee-Sun Cho, Liliana Cifuentes, Elizabeth Clark, Matthew Clark, Andrea Clarke, Elizabeth A. Clutterbuck, Sarah L.K. Collins, Christopher P. Conlon, Sean Connarty, Naomi Coombes, Cushla Cooper, Rachel Cooper, Lynne Cornelissen, Tumena Corrah, Catherine Cosgrove, Tony Cox, Wendy E.M. Crocker, Sarah Crosbie, Lorraine Cullen, Dan Cullen, Debora R.M.F. Cunha, Christina Cunningham, Fiona C. Cuthbertson, Suzete N. Farias Da Guarda, Larissa P. da Silva, Brad E. Damratoski, Zsofia Danos, Maria T.D.C. Dantas, Paula Darroch, Mehreen S. Datoo, Chandrabali Datta, Malika Davids, Sarah L. Davies, Hannah Davies, Elizabeth Davis, Judith Davis, John Davis, Maristela M.D. De Nobrega, Lis Moreno De Oliveira Kalid, David Dearlove, Tesfaye Demissie, Amisha Desai, Stefania Di Marco, Claudio Di Maso, Maria I.S. Dinelli, Tanya Dinesh, Claire Docksey, Christina Dold, Tao Dong, Francesca R. Donnellan, Tannyth Dos Santos, Thainá G. dos Santos, Erika Pachecho Dos Santos, Naomi Douglas, Charlotte Downing, Jonathan Drake, Rachael Drake-Brockman, Kimberley Driver, Ruth Drury, Susanna J. Dunachie, Benjamin S. Durham, Lidiana Dutra, Nicholas J.W. Easom, Samual van Eck, Mandy Edwards, Nick J. Edwards, Omar M. El Muhanna, Sean C. Elias, Mike Elmore, Marcus English, Alisgair Esmail, Yakub Moosa Essack, Eoghan Farmer, Mutjaba Farooq, Madi Farrar, Leonard Farrugia, Beverley Faulkner, Sofiya Fedosyuk, Sally Felle, Carla Ferreira Da Silva, Samantha Field, Richard Fisher, Amy Flaxman, James Fletcher, Hazel Fofie, Henry Fok, Karen J. Ford, Jamie Fowler, Pedro H.A. Fraiman, Emma Francis, Marilia M. Franco, John Frater, Marilúcia S.M. Freire, Samantha H. Fry, Sabrina Fudge, Julie Furze, Michelle Fuskova, Pablo Galian-Rubio, Eva Galiza, Harriet Garlant, Madita Gavrila, Ailsa Geddes, Karyna A. Gibbons, Ciaran Gilbride, Hardeep Gill, Sharon Glynn, Kerry Godwin, Karishma Gokani, Ursula Carvalho Goldoni, Maria Goncalves, Isabela G.S. Gonzalez, Jayne Goodwin, Amina Goondiwala, Katherine Gordon-Quayle, Giacomo Gorini, Janet Grab, Lara Gracie, Melanie Greenland, Nicola Greenwood, Johann Greffrath, Marisa M. Groenewald, Leonardo Grossi, Gaurav Gupta, Mark Hackett, Bassam Hallis, Mainga Hamaluba, Elizabeth Hamilton, Joseph Hamlyn, Daniel Hammersley, Aidan T. Hanrath, Brama Hanumunthadu, Stephanie A. Harris, Clair Harris, Tara Harris, Thomas D. Harrison, Daisy Harrison, Thomas C. Hart, Birgit Hartnell, Shadin Hassan, John Haughney, Sophia Hawkins, Jodie Hay, Ian Head, John Henry, Macarena Hermosin Herrera, David B. Hettle, Jennifer Hill, Gina Hodges, Elizea Horne, Mimi M. Hou, Catherine Houlihan, Elizabeth Howe, Nicola Howell, Jonathan Humphreys, Holly E. Humphries, Katrina Hurley, Claire Huson, Angela Hyder-Wright, Catherine Hyams, Sabina Ikram, Alka Ishwarbhai, Monica Ivan, Poppy Iveson, Vidyashankara Iyer, Frederic Jackson, Jeanne De Jager, Shameem Jaumdally, Helen Jeffers, Natasha Jesudason, Bryony Jones, Kathryn Jones, Elizabeth Jones, Christopher Jones, Marianna Rocha Jorge, Aylin Jose, Amar Joshi, Eduardo A.M.S. Júnior, Joanne Kadziola, Reshma Kailath, Faeeza Kana, Konstantinos Karampatsas, Mwila Kasanyinga, Jade Keen, Elizabeth J. Kelly, Dearbhla M. Kelly, Debbie Kelly, Sarah Kelly, David Kerr, Renato de Ávila Kfouri, Liaquat Khan, Baktash Khozoee, Sarah Kidd, Annabel Killen, Jasmin Kinch, Patrick Kinch, Lloyd D.W. King, Thomas B. King, Lucy Kingham, Paul Klenerman, Francesca Knapper, Julian C. Knight, Daniel Knott, Stanislava Koleva, Matilda Lang, Gail Lang, Colin W. Larkworthy, Jessica P.J. Larwood, Rebecca Law, Erica M. Lazarus, Amanda Leach, Emily A. Lees, Nana-Marie Lemm, Alvaro Lessa, Stephanie Leung, Yuanyuan Li, Amelia M. Lias, Kostas Liatsikos, Aline Linder, Samuel Lipworth, Shuchang Liu, Xinxue Liu, Adam Lloyd, Stephanie Lloyd, Lisa Loew, Raquel Lopez Ramon, Leandro Lora, Vicki Lowthorpe, Kleber Luz, Jonathan C. MacDonald, Gordon MacGregor, Meera Madhavan, David O. Mainwaring, Edson Makambwa, Rebecca Makinson, Mookho Malahleha, Ross Malamatsho, Garry Mallett, Kushal Mansatta, Takalani Maoko, Katlego Mapetla, Natalie G. Marchevsky, Spyridoula Marinou, Emma Marlow, Gabriela N. Marques, Paula Marriott, Richard P. Marshall, Julia L. Marshall, Flávia J. Martins, Masebole Masenya, Mduduzi Masilela, Shauna K. Masters, Moncy Mathew, Hosea Matlebjane, Kedidimetse Matshidiso, Olga Mazur, Andrea Mazzella, Hugh McCaughan, Joanne McEwan, Joanna McGlashan, Lorna McInroy, Zoe McIntyre, Daniela McLenaghan, Nicky McRobert, Steve McSwiggan, Clare Megson, Savviz Mehdipour, Wilma Meijs, Renata N.Á. Mendonça, Alexander J. Mentzer, Neginsadat Mirtorabi, Celia Mitton, Sibusiso Mnyakeni, Fiona Moghaddas, Kgaogelo Molapo, Mapule Moloi, Maria Moore, M. Isabel Moraes-Pinto, Marni Moran, Ella Morey, Róisín Morgans, Susan Morris, Sheila Morris, Helen C. Morris, Franca Morselli, Gertraud Morshead, Richard Morter, Lynelle Mottal, Andrew Moultrie, Nathifa Moya, Mushiya Mpelembue, Sibekezelo Msomi, Yvonne Mugodi, Ekta Mukhopadhyay, Jilly Muller, Alasdair Munro, Claire Munro, Sarah Murphy, Philomena Mweu, Celia Hatsuko Myasaki, Gurudutt Naik, Kush Naker, Eleni Nastouli, Abida Nazir, Bongani Ndlovu, Fabio Neffa, Cecilia Njenga, Helena Noal, Andrés Noé, Gabrielle Novaes, Fay L. Nugent, Géssika Nunes, Katie O'Brien, Daniel O'Connor, Miranda Odam, Suzette Oelofse, Blanche Oguti, Victoria Olchawski, Neil J. Oldfield, Marianne G. Oliveira, Catarina Oliveira, Angela Oosthuizen, Paula O'Reilly, Piper Osborne, David R.J. Owen, Lydia Owen, Daniel Owens, Nelly Owino, Mihaela Pacurar, Brenda V.B. Paiva, Edna M.F. Palhares, Susan Palmer, Sivapriyai Parkinson, Helena M.R.T. Parracho, Karen Parsons, Dipak Patel, Bhumika Patel, Faeezah Patel, Kelly Patel, Maia Patrick-Smith, Ruth O. Payne, Yanchun Peng, Elizabeth J. Penn, Anna Pennington, Marco Polo Peralta Alvarez, James Perring, Nicola Perry, Rubeshan Perumal, Sahir Petkar, Tricia Philip, Daniel J. Phillips, Jennifer Phillips, Mary Kgomotso Phohu, Lorinda Pickup, Sonja Pieterse, Jo Piper, Dimitra Pipini, Mary Plank, Joan Du Plessis, Samuel Pollard, Jennifer Pooley, Anil Pooran, Ian Poulton, Claire Powers, Fernando B. Presa, David A. Price, Vivien Price, Marcelo Primeira, Pamela C. Proud, Samuel Provstgaard-Morys, Sophie Pueschel, David Pulido, Sheena Quaid, Ria Rabara, Alexandra Radford, Kajal Radia, Durga Rajapaska, Thurkka Rajeswaran, Alberto San Francisco Ramos, Fernando Ramos Lopez, Tommy Rampling, Jade Rand, Helen Ratcliffe, Tom Rawlinson, David Rea, Byron Rees, Jesús Reiné, Mila Resuello-Dauti, Emilia Reyes Pabon, Carla M. Ribiero, Marivic Ricamara, Alex Richter, Neil Ritchie, Adam J. Ritchie, Alexander J. Robbins, Hannah Roberts, Ryan E. Robinson, Hannah Robinson, Talita T. Rocchetti, Beatriz Pinho Rocha, Sophie Roche, Christine Rollier, Louisa Rose, Amy L. Ross Russell, Lindie Rossouw, Simon Royal, Indra Rudiansyah, Sarah Ruiz, Stephen Saich, Claudia Sala, Jessica Sale, Ahmed M. Salman, Natalia Salvador, Stephannie Salvador, Milla Sampaio, Annette D. Samson, Amada Sanchez-Gonzalez, Helen Sanders, Katherine Sanders, Erika Santos, Mayara F.S. Santos Guerra, Iman Satti, Jack E. Saunders, Caroline Saunders, Aakifah Sayed, Ina Schim van der Loeff, Annina B. Schmid, Ella Schofield, Gavin Screaton, Samiullah Seddiqi, Rameswara R. Segireddy, Roberta Senger, Sonia Serrano, Rajiv Shah, Imam Shaik, Hannah E. Sharpe, Katherine Sharrocks, Robert Shaw, Adam Shea, Amy Shepherd, James G. Shepherd, Farah Shiham, Emad Sidhom, Sarah E. Silk, Antonio Carlos da Silva Moraes, Gilberto Silva-Junior, Laura Silva-Reyes, Anderson D. Silveira, Mariana B.V. Silveira, Jaisi Sinha, Donal T. Skelly, Daniel C. Smith, Nick Smith, Holly E. Smith, David J. Smith, Catherine C. Smith, Airanuédida Soares, Tiago Soares, Carla Solórzano, Guilherme L. Sorio, Kim Sorley, Tiffany Sosa-Rodriguez, Cinthia M.C.D.L. Souza, Bruno S.D.F. Souza, Alessandra R. Souza, Alexandra J. Spencer, Fernanda Spina, Louise Spoors, Lizzie Stafford, Imogen Stamford, Igor Starinskij, Ricardo Stein, Jill Steven, Lisa Stockdale, Lisa V. Stockwell, Louise H. Strickland, Arabella C. Stuart, Ann Sturdy, Natalina Sutton, Anna Szigeti, Abdessamad Tahiri-Alaoui, Rachel Tanner, Carol Taoushanis, Alexander W. Tarr, Keja Taylor, Ursula Taylor, Iona Jennifer Taylor, Justin Taylor, Rebecca te Water Naude, Yrene Themistocleous, Andreas Themistocleous, Merin Thomas, Kelly Thomas, Tonia M. Thomas, Asha Thombrayil, Fawziyah Thompson, Amber Thompson, Kevin Thompson, Ameeka Thompson, Julia Thomson, Viv Thornton-Jones, Patrick J. Tighe, Lygia Accioly Tinoco, Gerlynn Tiongson, Bonolo Tladinyane, Michele Tomasicchio, Adriana Tomic, Susan Tonks, James Towner, Nguyen Tran, Julia Tree, Gerry Trillana, Charlotte Trinham, Rose Trivett, Adam Truby, Betty Lebogang Tsheko, Aadil Turabi, Richard Turner, Cheryl Turner, Marta Ulaszewska, Benjamin R. Underwood, Rachel Varughese, Dennis Verbart, Marije Verheul, Iason Vichos, Taiane Vieira, Claire S. Waddington, Laura Walker, Erica Wallis, Matthew Wand, Deborah Warbick, Theresa Wardell, George Warimwe, Sarah C. Warren, Bridget Watkins, Ekaterina Watson, Stewart Webb, Alice Webb-Bridges, Angela Webster, Jessica Welch, Jeanette Wells, Alison West, Caroline White, Rachel White, Paul Williams, Rachel L. Williams, Rebecca Winslow, Mark Woodyer, Andrew T. Worth, Danny Wright, Marzena Wroblewska, Andy Yao, Rafael Zimmer, Dalila Zizi, Peter Zuidewind, Group, Oxford COVID Vaccine Trial, Toshner, Mark [0000-0002-3969-6143], and Apollo - University of Cambridge Repository
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Male ,COVID-19/prevention & control ,030204 cardiovascular system & hematology ,law.invention ,South Africa ,0302 clinical medicine ,Randomized controlled trial ,law ,Oxford COVID Vaccine Trial Group ,wc_505 ,Single-Blind Method ,030212 general & internal medicine ,Young adult ,11 Medical and Health Sciences ,wa_105 ,Covid19 ,General Medicine ,Articles ,Middle Aged ,Treatment Outcome ,Cohort ,Perspective ,Female ,Brazil ,Adult ,medicine.medical_specialty ,COVID-19 Vaccines ,Adolescent ,qw_806 ,qw_805 ,03 medical and health sciences ,Young Adult ,Double-Blind Method ,Conjugate vaccine ,Internal medicine ,General & Internal Medicine ,ChAdOx1 nCoV-19 ,medicine ,Humans ,Adverse effect ,Aged ,business.industry ,SARS-CoV-2 ,COVID-19 ,Viral Vaccines ,Vaccine efficacy ,Interim analysis ,United Kingdom ,Clinical trial ,bf023de6 ,business ,COVID-19 Vaccines/adverse effects - Abstract
BACKGROUND: A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. \ud \ud \ud METHODS: This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. \ud \ud \ud FINDINGS: Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0-75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4-97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8-80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3-4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. \ud \ud \ud INTERPRETATION: ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials. \ud \ud \ud FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, Bill & Melinda Gates Foundation, Lemann Foundation, Rede D'Or, Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca.
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- 2020
5. Safety and immunogenicity of ChAdOx1 nCoV-19 vaccine administered in a prime-boost regimen in young and old adults (COV002): a single-blind, randomised, controlled, phase 2/3 trial
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Maheshi N Ramasamy, Angela M Minassian, Katie J Ewer, Amy L Flaxman, Pedro M Folegatti, Daniel R Owens, Merryn Voysey, Parvinder K Aley, Brian Angus, Gavin Babbage, Sandra Belij-Rammerstorfer, Lisa Berry, Sagida Bibi, Mustapha Bittaye, Katrina Cathie, Harry Chappell, Sue Charlton, Paola Cicconi, Elizabeth A Clutterbuck, Rachel Colin-Jones, Christina Dold, Katherine R W Emary, Sofiya Fedosyuk, Michelle Fuskova, Diane Gbesemete, Catherine Green, Bassam Hallis, Mimi M Hou, Daniel Jenkin, Carina C D Joe, Elizabeth J Kelly, Simon Kerridge, Alison M Lawrie, Alice Lelliott, May N Lwin, Rebecca Makinson, Natalie G Marchevsky, Yama Mujadidi, Alasdair P S Munro, Mihaela Pacurar, Emma Plested, Jade Rand, Thomas Rawlinson, Sarah Rhead, Hannah Robinson, Adam J Ritchie, Amy L Ross-Russell, Stephen Saich, Nisha Singh, Catherine C Smith, Matthew D Snape, Rinn Song, Richard Tarrant, Yrene Themistocleous, Kelly M Thomas, Tonya L Villafana, Sarah C Warren, Marion E E Watson, Alexander D Douglas, Adrian V S Hill, Teresa Lambe, Sarah C Gilbert, Saul N Faust, Andrew J Pollard, Jeremy Aboagye, Kelly Adams, Aabidah Ali, Elizabeth R. Allen, Lauren Allen, Jennifer L. Allison, Foteini Andritsou, Rachel Anslow, Edward H. Arbe-Barnes, Megan Baker, Natalie Baker, Philip Baker, Ioana Baleanu, Debbie Barker, Eleanor Barnes, Jordan R. Barrett, Kelly Barrett, Louise Bates, Alexander Batten, Kirsten Beadon, Rebecca Beckley, Duncan Bellamy, Adam Berg, Laura Bermejo, Eleanor Berrie, Amy Beveridge, Kevin Bewley, Else M. Bijker, Geeta Birch, Luke Blackwell, Heather Bletchly, Caitlin L. Blundell, Susannah R. Blundell, Emma Bolam, Elena Boland, Daan Bormans, Nicola Borthwick, Konstantinos Boukas, Thomas Bower, Francesca Bowring, Amy Boyd, Tanja Brenner, Phillip Brown, Charlie Brown-O'Sullivan, Scott Bruce, Emily Brunt, Jamie Burbage, Joshua Burgoyne, Karen R. Buttigieg, Nicholas Byard, Ingrid Cabera Puig, Susana Camara, Michelangelo Cao, Federica Cappuccini, Melanie Carr, Miles W. Carroll, Paul Cashen, Ana Cavey, Jim Chadwick, Ruth Challis, David Chapman, David Charles, Irina Chelysheva, Jee-Sun Cho, Liliana Cifuentes, Elizabeth Clark, Sarah Collins, Christopher P. Conlon, Naomi S. Coombes, Rachel Cooper, Cushla Cooper, Wendy E.M. Crocker, Sarah Crosbie, Dan Cullen, Christina Cunningham, Fiona Cuthbertson, Brad E. Datoo, Lynne Dando, Mehreen S. Datoo, Chandrabali Datta, Hannah Davies, Sarah Davies, Elizabeth J. Davis, Judith Davis, David Dearlove, Tesfaye Demissie, Stefania Di Marco, Claudio Di Maso, Danielle DiTirro, Claire Docksey, Tao Dong, Francesca R. Donnellan, Naomi Douglas, Charlotte Downing, Jonathan Drake, Rachael Drake-Brockman, Ruth E. Drury, Susanna J. Dunachie, Christopher J. Edwards, Nick J. Edwards, Omar El Muhanna, Sean C. Elias, Ryan S. Elliott, Michael J. Elmore, Marcus Rex English, Sally Felle, Shuo Feng, Carla Ferreira Da Silva, Samantha Field, Richard Fisher, Carine Fixmer, Karen J. Ford, Jamie Fowler, Emma Francis, John Frater, Julie Furze, Pablo Galian-Rubio, Celine Galloway, Harriet Garlant, Madita Gavrila, Felicity Gibbons, Karyna Gibbons, Ciaran Gilbride, Hardeep Gill, Kerry Godwin, Katherine Gordon-Quayle, Giacomo Gorini, Lyndsey Goulston, Caroline Grabau, Lara Gracie, Nichola Graham, Nicola Greenwood, Oliver Griffiths, Gaurav Gupta, Elizabeth Hamilton, Brama Hanumunthadu, Stephanie A. Harris, Tara Harris, Daisy Harrison, Thomas C. Hart, Birgit Hartnell, Louise Haskell, Sophia Hawkins, John Aaron Henry, Macarena Hermosin Herrera, David Hill, Jennifer Hill, Gina Hodges, Susanne H.C. Hodgson, Katie L. Horton, Elizabeth Howe, Nicola Howell, Jessica Howes, Ben Huang, Jonathan Humphreys, Holly E. Humphries, Poppy Iveson, Frederic Jackson, Susan Jackson, Sam Jauregui, Helen Jeffers, Bryony Jones, Christine E. Jones, Elizabeth Jones, Kathryn Jones, Amar Joshi, Reshma Kailath, Jade Keen, Dearbhla M. Kelly, Sarah Kelly, Debbie Kelly, David Kerr, Liaquat Khan, Baktash Khozoee, Annabel Killen, Jasmin Kinch, Lloyd D.W. King, Thomas B. King, Lucy Kingham, Paul Klenerman, Julian C. Knight, Daniel Knott, Stanislava Koleva, Gail Lang, Colin W. Larkworthy, Jessica P.J. Larwood, Rebecca Law, Arlene Lee, Kim Y.N. Lee, Emily A. Lees, Stephanie Leung, Yuanyuan Li, Amelia M. Lias, Aline Linder, Samuel Lipworth, Shuchang Liu, Xinxue Liu, Stephanie Lloyd, Lisa Loew, Raquel Lopez Ramon, Meera Madhavan, David O. Mainwaring, Garry Mallett, Kushal Mansatta, Spyridoula Marinou, Phedra Marius, Emma Marlow, Paula Marriott, Julia L. Marshall, Jane Martin, Shauna Masters, Joanne McEwan, Joanna L. McGlashan, Lorna McInroy, Nicky McRobert, Clare Megson, Alexander J. Mentzer, Neginsadat Mirtorabi, Celia Mitton, Maria Moore, Marni Moran, Ella Morey, Róisín Morgans, Susan J. Morris, Hazel Morrison Morrison, Gertraud Morshead, Richard Morter, Nathifa A. Moya, Ekta Mukhopadhyay, Jilly Muller, Claire Munro, Sarah Murphy, Philomena Mweu, Andrés Noé, Fay L. Nugent, Katie O'Brien, Daniel O'Connor, Blanché Oguti, Victoria Olchawski, Catarina Oliveira, Peter John O'Reilly, Piper Osborne, Lydia Owen, Nelly Owino, Panagiotis Papageorgiou, Helena Parracho, Karen Parsons, Bhumika Patel, Maia Patrick-Smith, Yanchun Peng, Elizabeth J. Penn, Marco Polo Peralta-Alvarez, James Perring, Christos Petropoulos, Daniel J. Phillips, Dimitra Pipini, Samuel Pollard, Ian Poulton, Danny Pratt, Laura Presland, Pamela C. Proud, Samuel Provstgaard-Morys, Sophie Pueschel, David Pulido, Ria Rabara, Kajal Radia, Durga Rajapaska, Fernando Ramos Lopez, Helen Ratcliffe, Sara Rayhan, Byron Rees, Emilia Reyes Pabon, Hannah Roberts, Isla Robertson, Sophie Roche, Christine S. Rollier, Rossana Romani, Zoe Rose, Indra Rudiansyah, Sabeha Sabheha, Stephannie Salvador, Helen Sanders, Katherine Sanders, Iman Satti, Chloe Sayce, Annina B. Schmid, Ella Schofield, Gavin Screaton, Cynthia Sedik, Samiullah Seddiqi, Rameswara R. Segireddy, Beatrice Selby, Imam Shaik, Hannah R. Sharpe, Robert Shaw, Adam Shea, Sarah Silk, Laura Silva-Reyes, Donal T. Skelly, David J. Smith, Daniel C. Smith, Nicholas Smith, Alexandra J. Spencer, Louise Spoors, Elizabeth Stafford, Imogen Stamford, Lisa Stockdale, David Stockley, Lisa V. Stockwell, Matthew Stokes, Louise H. Strickland, Arabella Stuart, Sulaiman Sulaiman, Eloise Summerton, Zoe Swash, Anna Szigeti, Abdessamad Tahiri-Alaoui, Rachel Tanner, Iona Taylor, Keja Taylor, Ursula Taylor, Rebecca te Water Naude, Andreas Themistocleous, Merin Thomas, Tonia M. Thomas, Amber Thompson, Kevin Thompson, Viv Thornton-Jones, Lan Tinh, Adriana Tomic, Susan Tonks, James Towner, Nguyen Tran, Julian A. Tree, Adam Truby, Cheryl Turner, Richard Turner, Marta Ulaszewska, Rachel Varughese, Dennis Verbart, Marije K. Verheul, Iason Vichos, Laura Walker, Matthew E. Wand, Bridget Watkins, Jessica Welch, Alison J. West, Caroline White, Rachel White, Paul Williams, Mark Woodyer, Andrew T. Worth, Daniel Wright, Terri Wrin, Xin Li Yao, Diana-Andreea Zbarcea, and Dalila Zizi
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Adult ,Male ,Pediatrics ,medicine.medical_specialty ,COVID-19 Vaccines ,Adolescent ,Immunization, Secondary ,Department of Error ,030204 cardiovascular system & hematology ,law.invention ,Young Adult ,03 medical and health sciences ,Immunogenicity, Vaccine ,0302 clinical medicine ,Randomized controlled trial ,law ,ChAdOx1 nCoV-19 ,medicine ,Humans ,Single-Blind Method ,030212 general & internal medicine ,Young adult ,Adverse effect ,Aged ,Aged, 80 and over ,Reactogenicity ,SARS-CoV-2 ,business.industry ,Age Factors ,COVID-19 ,Articles ,General Medicine ,Middle Aged ,Clinical trial ,Vaccination ,Regimen ,Immunoglobulin G ,Cohort ,Female ,business - Abstract
BACKGROUND: Older adults (aged ≥70 years) are at increased risk of severe disease and death if they develop COVID-19 and are therefore a priority for immunisation should an efficacious vaccine be developed. Immunogenicity of vaccines is often worse in older adults as a result of immunosenescence. We have reported the immunogenicity of a novel chimpanzee adenovirus-vectored vaccine, ChAdOx1 nCoV-19, in young adults, and now describe the safety and immunogenicity of this vaccine in a wider range of participants, including adults aged 70 years and older. METHODS: In this report of the phase 2 component of a single-blind, randomised, controlled, phase 2/3 trial (COV002), healthy adults aged 18 years and older were enrolled at two UK clinical research facilities, in an age-escalation manner, into 18-55 years, 56-69 years, and 70 years and older immunogenicity subgroups. Participants were eligible if they did not have severe or uncontrolled medical comorbidities or a high frailty score (if aged ≥65 years). First, participants were recruited to a low-dose cohort, and within each age group, participants were randomly assigned to receive either intramuscular ChAdOx1 nCoV-19 (2·2 × 1010 virus particles) or a control vaccine, MenACWY, using block randomisation and stratified by age and dose group and study site, using the following ratios: in the 18-55 years group, 1:1 to either two doses of ChAdOx1 nCoV-19 or two doses of MenACWY; in the 56-69 years group, 3:1:3:1 to one dose of ChAdOx1 nCoV-19, one dose of MenACWY, two doses of ChAdOx1 nCoV-19, or two doses of MenACWY; and in the 70 years and older, 5:1:5:1 to one dose of ChAdOx1 nCoV-19, one dose of MenACWY, two doses of ChAdOx1 nCoV-19, or two doses of MenACWY. Prime-booster regimens were given 28 days apart. Participants were then recruited to the standard-dose cohort (3·5-6·5 × 1010 virus particles of ChAdOx1 nCoV-19) and the same randomisation procedures were followed, except the 18-55 years group was assigned in a 5:1 ratio to two doses of ChAdOx1 nCoV-19 or two doses of MenACWY. Participants and investigators, but not staff administering the vaccine, were masked to vaccine allocation. The specific objectives of this report were to assess the safety and humoral and cellular immunogenicity of a single-dose and two-dose schedule in adults older than 55 years. Humoral responses at baseline and after each vaccination until 1 year after the booster were assessed using an in-house standardised ELISA, a multiplex immunoassay, and a live severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) microneutralisation assay (MNA80). Cellular responses were assessed using an ex-vivo IFN-γ enzyme-linked immunospot assay. The coprimary outcomes of the trial were efficacy, as measured by the number of cases of symptomatic, virologically confirmed COVID-19, and safety, as measured by the occurrence of serious adverse events. Analyses were by group allocation in participants who received the vaccine. Here, we report the preliminary findings on safety, reactogenicity, and cellular and humoral immune responses. This study is ongoing and is registered with ClinicalTrials.gov, NCT04400838, and ISRCTN, 15281137. FINDINGS: Between May 30 and Aug 8, 2020, 560 participants were enrolled: 160 aged 18-55 years (100 assigned to ChAdOx1 nCoV-19, 60 assigned to MenACWY), 160 aged 56-69 years (120 assigned to ChAdOx1 nCoV-19: 40 assigned to MenACWY), and 240 aged 70 years and older (200 assigned to ChAdOx1 nCoV-19: 40 assigned to MenACWY). Seven participants did not receive the boost dose of their assigned two-dose regimen, one participant received the incorrect vaccine, and three were excluded from immunogenicity analyses due to incorrectly labelled samples. 280 (50%) of 552 analysable participants were female. Local and systemic reactions were more common in participants given ChAdOx1 nCoV-19 than in those given the control vaccine, and similar in nature to those previously reported (injection-site pain, feeling feverish, muscle ache, headache), but were less common in older adults (aged ≥56 years) than younger adults. In those receiving two standard doses of ChAdOx1 nCoV-19, after the prime vaccination local reactions were reported in 43 (88%) of 49 participants in the 18-55 years group, 22 (73%) of 30 in the 56-69 years group, and 30 (61%) of 49 in the 70 years and older group, and systemic reactions in 42 (86%) participants in the 18-55 years group, 23 (77%) in the 56-69 years group, and 32 (65%) in the 70 years and older group. As of Oct 26, 2020, 13 serious adverse events occurred during the study period, none of which were considered to be related to either study vaccine. In participants who received two doses of vaccine, median anti-spike SARS-CoV-2 IgG responses 28 days after the boost dose were similar across the three age cohorts (standard-dose groups: 18-55 years, 20 713 arbitrary units [AU]/mL [IQR 13 898-33 550], n=39; 56-69 years, 16 170 AU/mL [10 233-40 353], n=26; and ≥70 years 17 561 AU/mL [9705-37 796], n=47; p=0·68). Neutralising antibody titres after a boost dose were similar across all age groups (median MNA80 at day 42 in the standard-dose groups: 18-55 years, 193 [IQR 113-238], n=39; 56-69 years, 144 [119-347], n=20; and ≥70 years, 161 [73-323], n=47; p=0·40). By 14 days after the boost dose, 208 (>99%) of 209 boosted participants had neutralising antibody responses. T-cell responses peaked at day 14 after a single standard dose of ChAdOx1 nCoV-19 (18-55 years: median 1187 spot-forming cells [SFCs] per million peripheral blood mononuclear cells [IQR 841-2428], n=24; 56-69 years: 797 SFCs [383-1817], n=29; and ≥70 years: 977 SFCs [458-1914], n=48). INTERPRETATION: ChAdOx1 nCoV-19 appears to be better tolerated in older adults than in younger adults and has similar immunogenicity across all age groups after a boost dose. Further assessment of the efficacy of this vaccine is warranted in all age groups and individuals with comorbidities. FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midlands NIHR Clinical Research Network, and AstraZeneca.
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- 2020
6. Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trial
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Pedro M Folegatti, Katie J Ewer, Parvinder K Aley, Brian Angus, Stephan Becker, Sandra Belij-Rammerstorfer, Duncan Bellamy, Sagida Bibi, Mustapha Bittaye, Elizabeth A Clutterbuck, Christina Dold, Saul N Faust, Adam Finn, Amy L Flaxman, Bassam Hallis, Paul Heath, Daniel Jenkin, Rajeka Lazarus, Rebecca Makinson, Angela M Minassian, Katrina M Pollock, Maheshi Ramasamy, Hannah Robinson, Matthew Snape, Richard Tarrant, Merryn Voysey, Catherine Green, Alexander D Douglas, Adrian V S Hill, Teresa Lambe, Sarah C Gilbert, Andrew J Pollard, Jeremy Aboagye, Kelly Adams, Aabidah Ali, Elizabeth Allen, Jennifer L. Allison, Rachel Anslow, Edward H. Arbe-Barnes, Gavin Babbage, Kenneth Baillie, Megan Baker, Natalie Baker, Philip Baker, Ioana Baleanu, Juliana Ballaminut, Eleanor Barnes, Jordan Barrett, Louise Bates, Alexander Batten, Kirsten Beadon, Rebecca Beckley, Eleanor Berrie, Lisa Berry, Amy Beveridge, Kevin R. Bewley, Else Margreet Bijker, Tracey Bingham, Luke Blackwell, Caitlin L. Blundell, Emma Bolam, Elena Boland, Nicola Borthwick, Thomas Bower, Amy Boyd, Tanja Brenner, Philip D. Bright, Charlie Brown-O'Sullivan, Emily Brunt, Jamie Burbage, Sharon Burge, Karen R. Buttigieg, Nicholas Byard, Ingrid Cabera Puig, Anna Calvert, Susana Camara, Michelangelo Cao, Federica Cappuccini, Melanie Carr, Miles W. Carroll, Victoria Carter, Katrina Cathie, Ruth J. Challis, Sue Charlton, Irina Chelysheva, Jee-Sun Cho, Paola Cicconi, Liliana Cifuentes, Helen Clark, Elizabeth Clark, Tom Cole, Rachel Colin-Jones, Christopher P. Conlon, Aislinn Cook, Naomi S. Coombes, Rachel Cooper, Catherine A. Cosgrove, Karen Coy, Wendy E.M. Crocker, Christina J. Cunningham, Brad E. Damratoski, Lynne Dando, Mehreen S. Datoo, Hannah Davies, Hans De Graaf, Tesfaye Demissie, Claudio Di Maso, Isabelle Dietrich, Tao Dong, Francesca R. Donnellan, Naomi Douglas, Charlotte Downing, Jonathan Drake, Rachael Drake-Brockman, Ruth Elizabeth Drury, Susanna Jane Dunachie, Nick J. Edwards, Frances D.L. Edwards, Chris J. Edwards, Sean C. Elias, Michael J. Elmore, Katherine R.W. Emary, Marcus Rex English, Susanne Fagerbrink, Sally Felle, Shuo Feng, Samantha Field, Carine Fixmer, Clare Fletcher, Karen J. Ford, Jamie Fowler, Polly Fox, Emma Francis, John Frater, Julie Furze, Michelle Fuskova, Eva Galiza, Diane Gbesemete, Ciaran Gilbride, Kerry Godwin, Giacomo Gorini, Lyndsey Goulston, Caroline Grabau, Lara Gracie, Zoe Gray, Lucy Belle Guthrie, Mark Hackett, Sandro Halwe, Elizabeth Hamilton, Joseph Hamlyn, Brama Hanumunthadu, Irasha Harding, Stephanie A. Harris, Andrew Harris, Daisy Harrison, Clare Harrison, Thomas C. Hart, Louise Haskell, Sophia Hawkins, Ian Head, John Aaron Henry, Jennifer Hill, Susanne H.C. Hodgson, Mimi M. Hou, Elizabeth Howe, Nicola Howell, Cecilia Hutlin, Sabina Ikram, Catherine Isitt, Poppy Iveson, Susan Jackson, Frederic Jackson, Sir William James, Megan Jenkins, Elizabeth Jones, Kathryn Jones, Christine E. Jones, Bryony Jones, Reshma Kailath, Konstantinos Karampatsas, Jade Keen, Sarah Kelly, Dearbhla Kelly, David Kerr, Simon Kerridge, Liaquat Khan, Uzma Khan, Annabel Killen, Jasmin Kinch, Thomas B. King, Lloyd King, Jade King, Lucy Kingham-Page, Paul Klenerman, Francesca Knapper, Julian C. Knight, Daniel Knott, Stanislava Koleva, Alexandra Kupke, Colin W. Larkworthy, Jessica P.J. Larwood, Anna Laskey, Alison M. Lawrie, Arlene Lee, Kim Yee Ngan Lee, Emily A Lees, Helen Legge, Alice Lelliott, Nana-Marie Lemm, Amelia M. Lias, Aline Linder, Samuel Lipworth, Xinxue Liu, Shuchang Liu, Raquel Lopez Ramon, May Lwin, Francesca Mabesa, Meera Madhavan, Garry Mallett, Kushal Mansatta, Ines Marcal, Spyridoula Marinou, Emma Marlow, Julia L. Marshall, Jane Martin, Joanne McEwan, Lorna McInroy, Gretchen Meddaugh, Alexander J. Mentzer, Neginsadat Mirtorabi, Maria Moore, Edward Moran, Ella Morey, Victoria Morgan, Susan Jane Morris, Hazel Morrison, Gertraud Morshead, Richard Morter, Yama F. Mujadidi, Jilly Muller, Tatiana Munera-Huertas, Claire Munro, Alasdair Munro, Sarah Murphy, Vincent J. Munster, Philomena Mweu, Andrés Noé, Fay L. Nugent, Elizabeth Nuthall, Katie O'Brien, Daniel O'Connor, Blanché Oguti, Jennifer L. Oliver, Catarina Oliveira, Peter John O'Reilly, Mairead Osborn, Piper Osborne, Cathy Owen, Daniel Owens, Nelly Owino, Mihaela Pacurar, Kaye Parker, Helena Parracho, Maia Patrick-Smith, Victoria Payne, Jennifer Pearce, Yanchun Peng, Marco Polo Peralta Alvarez, James Perring, Katja Pfafferott, Dimitra Pipini, Emma Plested, Helen Pluess-Hall, Katrina Pollock, Ian Poulton, Laura Presland, Samuel Provstgaard-Morys, David Pulido, Kajal Radia, Fernando Ramos Lopez, Jade Rand, Helen Ratcliffe, Thomas Rawlinson, Sarah Rhead, Amy Riddell, Adam John Ritchie, Hannah Roberts, Joanna Robson, Sophie Roche, Cornelius Rohde, Christine S. Rollier, Rossana Romani, Indra Rudiansyah, Stephen Saich, Sara Sajjad, Stephannie Salvador, Lidia Sanchez Riera, Helen Sanders, Katherine Sanders, Shari Sapaun, Chloe Sayce, Ella Schofield, Gavin Screaton, Beatrice Selby, Calum Semple, Hannah R. Sharpe, Imam Shaik, Adam Shea, Holly Shelton, Sarah Silk, Laura Silva-Reyes, Donal T. Skelly, Heather Smee, Catherine C. Smith, David J. Smith, Rinn Song, Alexandra J. Spencer, Elizabeth Stafford, Amy Steele, Elena Stefanova, Lisa Stockdale, Anna Szigeti, Abdessamad Tahiri-Alaoui, Moira Tait, Helen Talbot, Rachel Tanner, Iona Jennifer Taylor, Victoria Taylor, Rebecca Te Water Naude, Nazia Thakur, Yrene Themistocleous, Andreas Themistocleous, Merin Thomas, Tonia M. Thomas, Amber Thompson, Samantha Thomson-Hill, Jennifer Tomlins, Susan Tonks, James Towner, Nguyen Tran, Julia A. Tree, Adam Truby, Kate Turkentine, Cheryl Turner, Nicola Turner, Sally Turner, Toby Tuthill, Marta Ulaszewska, Rachel Varughese, Neeltje Van Doremalen, Kristin Veighey, Marije K. Verheul, Iason Vichos, Elia Vitale, Laura Walker, Marion E.E. Watson, Benjamin Welham, Julie Wheat, Caroline White, Rachel White, Andrew T. Worth, Danny Wright, Suzie Wright, Xin Li Yao, Yasmine Yau, and Hodgson, S
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Male ,T-Lymphocytes ,Booster dose ,030204 cardiovascular system & hematology ,Antibodies, Viral ,law.invention ,0302 clinical medicine ,Immunogenicity, Vaccine ,Randomized controlled trial ,law ,Oxford COVID Vaccine Trial Group ,Medicine ,Single-Blind Method ,030212 general & internal medicine ,11 Medical and Health Sciences ,Viral Vaccine ,Immunogenicity ,Covid19 ,General Medicine ,Analgesics, Non-Narcotic ,Vaccination ,Spike Glycoprotein, Coronavirus ,Female ,Coronavirus Infections ,Life Sciences & Biomedicine ,Adult ,medicine.medical_specialty ,COVID-19 Vaccines ,UNCOVER ,Genetic Vectors ,Pneumonia, Viral ,Immunization, Secondary ,Department of Error ,Article ,03 medical and health sciences ,Betacoronavirus ,Medicine, General & Internal ,Internal medicine ,General & Internal Medicine ,Humans ,Adverse effect ,Pandemics ,Acetaminophen ,Reactogenicity ,Science & Technology ,business.industry ,SARS-CoV-2 ,COVID-19 ,Viral Vaccines ,Antibodies, Neutralizing ,United Kingdom ,Clinical trial ,Immunoglobulin G ,Adenoviruses, Simian ,business ,ACUTE RESPIRATORY SYNDROME - Abstract
Background: The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might be curtailed by vaccination. We assessed the safety, reactogenicity, and immunogenicity of a viral vectored coronavirus vaccine that expresses the spike protein of SARS-CoV-2. Methods: We did a phase 1/2, single-blind, randomised controlled trial in five trial sites in the UK of a chimpanzee adenovirus-vectored vaccine (ChAdOx1 nCoV-19) expressing the SARS-CoV-2 spike protein compared with a meningococcal conjugate vaccine (MenACWY) as control. Healthy adults aged 18–55 years with no history of laboratory confirmed SARS-CoV-2 infection or of COVID-19-like symptoms were randomly assigned (1:1) to receive ChAdOx1 nCoV-19 at a dose of 5 × 10 10 viral particles or MenACWY as a single intramuscular injection. A protocol amendment in two of the five sites allowed prophylactic paracetamol to be administered before vaccination. Ten participants assigned to a non-randomised, unblinded ChAdOx1 nCoV-19 prime-boost group received a two-dose schedule, with the booster vaccine administered 28 days after the first dose. Humoral responses at baseline and following vaccination were assessed using a standardised total IgG ELISA against trimeric SARS-CoV-2 spike protein, a muliplexed immunoassay, three live SARS-CoV-2 neutralisation assays (a 50% plaque reduction neutralisation assay [PRNT 50]; a microneutralisation assay [MNA 50, MNA 80, and MNA 90]; and Marburg VN), and a pseudovirus neutralisation assay. Cellular responses were assessed using an ex-vivo interferon-γ enzyme-linked immunospot assay. The co-primary outcomes are to assess efficacy, as measured by cases of symptomatic virologically confirmed COVID-19, and safety, as measured by the occurrence of serious adverse events. Analyses were done by group allocation in participants who received the vaccine. Safety was assessed over 28 days after vaccination. Here, we report the preliminary findings on safety, reactogenicity, and cellular and humoral immune responses. The study is ongoing, and was registered at ISRCTN, 15281137, and ClinicalTrials.gov, NCT04324606. Findings: Between April 23 and May 21, 2020, 1077 participants were enrolled and assigned to receive either ChAdOx1 nCoV-19 (n=543) or MenACWY (n=534), ten of whom were enrolled in the non-randomised ChAdOx1 nCoV-19 prime-boost group. Local and systemic reactions were more common in the ChAdOx1 nCoV-19 group and many were reduced by use of prophylactic paracetamol, including pain, feeling feverish, chills, muscle ache, headache, and malaise (all p80 and in 35 (100%) participants when measured in PRNT 50. After a booster dose, all participants had neutralising activity (nine of nine in MNA 80 at day 42 and ten of ten in Marburg VN on day 56). Neutralising antibody responses correlated strongly with antibody levels measured by ELISA (R 2=0·67 by Marburg VN; p
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- 2020
7. Author Correction: Phase 1/2 trial of SARS-CoV-2 vaccine ChAdOx1 nCoV-19 with a booster dose induces multifunctional antibody responses
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M Datoo, Thomas A. Rawlinson, C Brown-O’Sullivan, Hodgson Shc., C White, B Oguti, Eleanor Berrie, N Moya, S Felle, H Sanders, Adam J. Ritchie, M M Hou, J Drake, E Brunt, D Rajapaksa, S Provstgaard-Morys, G Gorini, Elizabeth Nuthall, J Burbage, C Munro, L Bates, J A Tree, E Y Jones, R Makinson, O E Muhanna, N Borthwick, Andreas C. Themistocleous, I Rudiansyah, Emary Krw., A Batten, D Jenkin, D J Smith, I Vichos, N Douglas, Susanna Dunachie, Hazel Morrison, S Marinou, P Osborne, A Szigeti, Bassam Hallis, Alexander J. Mentzer, Christina Dold, T Brenner, K Parker, E H Arbe-Barnes, G Meddaugh, S Lipworth, J Towner, N Turner, E Hamilton, C Downing, L Gracie, C J Cunningham, P Matthews, H Humphries, Y Peng, N Tran, I Satti, N Byard, Shuo Feng, Ciaran Gilbride, R E Drury, K Radia, D Bellamy, R Tarrant, E Howe, Daniel J. Phillips, L Cifuentes, X L Yao, Elizabeth R. Allen, L Allen, B Hanumunthadu, K Godwin, E Francis, K Sanders, H Parracho, R Kailath, N Baker, J McGlashan, S Rhead, F Jackson, S Tonks, A Ali, S Murphy, Larwood Jpj., L Tinh, T Wrin, A Linder, Irina Chelysheva, Catherine M. Green, Elizabeth J. Kelly, C Datta, B Khozoee, H Roberts, Miles W. Carroll, P M Folegatti, C V Arancibia-Cárcamo, Julian C. Knight, E Marlow, P C Proud, A Truby, Crocker Wem., Hannah Robinson, J Keen, E J Penn, L Loew, Elizabeth A. Clutterbuck, D Zizi, N Owino, E Boland, J McEwan, N G Marchevsky, E Morey, Brian Angus, M P Peralta Alvarez, P Mweu, A Killen, E A Lees, Amy Boyd, Watson Mee., A Tomic, M E Wand, T B King, S Jauregui, C W Larkworthy, S Salvador, I J Taylor, D Pulido, Fay L. Nugent, M Patrick-Smith, A T Worth, Merryn Voysey, S A Harris, T M Thomas, A Shea, Teresa Lambe, L Blackwell, R Halkerston, Katie J. Ewer, D O’Connor, L Kingham-Page, P Brown, R Fisher, S J Morris, B Huang, Michelle Fuskova, D O’Donnell, A Lelliott, E R Pabon, J Kinch, M Thomas, H Garlant, M N Ramasamy, Daniel B. Wright, K Mansatta, K Taylor, F Cappuccini, D Kerr, Jordan R. Barrett, E Schofield, Yrene Themistocleous, R Varughese, A Beveridge, M R English, D Pipini, Sandra Belij-Rammerstorfer, S Camara, F Ramos Lopez, N Howell, J Frater, J Aboagye, X Liu, A Noé, L Silva-Reyes, Huw Davies, F R Donnellan, Alison M. Lawrie, Andrew J. Pollard, E Bolam, C Sedik, Hill Avs., Simon Kerridge, R te Water Naude, Alexandra J. Spencer, C Petropoulos, Maria Moore, K Jeffery, C Oliveria, K Pfafferott, G Gupta, Catherine C. Smith, A M Lias, G Morshead, D DiTirro, N Mirtorabi, H Ratcliffe, M J Elmore, R Lopez Ramon, S Jackson, K Jones, Y Li, Stephen Taylor, M Madhavan, I Shaik, Yama F Mujadidi, J Alderson, I Baleanu, Matthew D. Snape, M Bittaye, P J O’Reilly, R White, K O’Brien, Breeze E. Cavell, J Muller, Kelly M. Thomas, M Cao, S Field, S Roche, R Tanner, D M Kelly, R Anslow, L King, Annina B. Schmid, P Iveson, Ian D. Poulton, R Song, C L Blundell, R Beckley, T Demissie, Jack Mellors, K J Ford, Sarah E. Silk, J Furze, D Harrison, K R Buttigieg, Amy Flaxman, J Chadwick, J A Henry, R Morgans, L McInroy, G Screaton, V Olchawski, S Liu, L Khan, R Morter, P Galian-Rubio, T C Hart, G Hodges, Abdessamad Tahiri-Alaoui, J Perring, S Hawkins, Emma Plested, S Koleva, B E Damratoski, L Walker, Lisa Stockdale, P Baker, G Mallett, Angela M. Minassian, E Stafford, M K Verheul, M Carr, D Knott, Nick J. Edwards, J Fowler, Sarah C. Gilbert, A Thompson, Hannah Sharpe, Andrew Gorringe, Marta Ulaszewska, Christine S. Rollier, C P Conlon, R Colin-Jones, C Turner, Eleanor Barnes, E Mukhopadhyay, S Bibi, E M Bijker, R Cooper, D T Skelly, N S Coombes, J L Marshall, Tao Dong, Jennifer Hill, C Di Maso, K Beadon, Alexander D. Douglas, Cho J-S., Sean C. Elias, Parvinder K. Aley, S Leung, Paul Klenerman, I Cabrera Puig, K R Bewley, E Clark, S Kelly, P Williams, J Hamlyn, Megan Baker, C F Da Silva, and R Drake-Brockman
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2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,General Medicine ,Booster dose ,Viral infection ,Virology ,General Biochemistry, Genetics and Molecular Biology ,law.invention ,Antibody response ,Randomized controlled trial ,law ,Medicine ,business - Published
- 2021
8. Pervasive differential splicing in Marek’s Disease Virus can discriminate CVI-988 vaccine strain from RB-1B virulent strain in chicken embryonic fibroblasts
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Paolo Ribeca, Abdessamad Tahiri-Alaoui, Stephen J. Spatz, Venugopal Nair, and Yashar Sadigh
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2. Zero hunger ,0303 health sciences ,Marek's disease ,animal structures ,030306 microbiology ,Viral pathogenesis ,animal diseases ,viruses ,Virulence ,Biology ,medicine.disease_cause ,biology.organism_classification ,Virology ,Herpesviridae ,Virus ,3. Good health ,Transcriptome ,03 medical and health sciences ,hemic and lymphatic diseases ,RNA splicing ,medicine ,Viral shedding ,030304 developmental biology - Abstract
Marek’s disease is a major scourge challenging poultry health worldwide. It is caused by the highly contagious Marek’s disease virus (MDV), an alphaherpesvirus. Here we show that, similar to other members of itsHerpesviridaefamily, MDV also presents a complex landscape of splicing events, most of which are uncharacterised and/or not annotated. Quite strikingly, and although the biological relevance of this fact is unknown, we found that a number of viral splicing isoforms are strain-specific despite the close sequence similarity of the strains considered, virulent RB-1B and vaccine CVI-988. We validated our findings by devising an assay that discriminates infections caused by the two strains in chicken embryonic fibroblasts based on the presence of some RNA species. To our knowledge, this study is the first ever to accomplish such a result, emphasizing how important a comprehensive knowledge of the viral transcriptome can be to understand viral pathogenesis.ImportanceMarek’s disease virus (MDV) causes an agro-economically important disease of chickens worldwide. Although commercial poultry are vaccinated against MDV, it is not possible to achieve sterilising immunity, and available vaccines can only protect chickens against the symptoms of the disease. Vaccinated chicken often become superinfected with virulent strains, shedding virus into the environment. The most effective MDV vaccine strain, CVI-988, shares >99% sequence identity with the prototype virulent virus strain RB-1B. Interestingly, our work shows that despite their almost identical sequences MDV strains CVI-988 and RB-1B have significantly different splicing profiles, and hence transcriptomes. We independently validated this discovery by detecting with real-time PCR some splicing isoforms expressed by MDV strain CVI-988 and absent in the transcriptome of the RB-1B strain. These results indicate that the coding potential of MDV might be much larger than previously thought, and suggest a likely underestimation of the role of the viral transcriptome in the pathogenesis and prevention of MDV.
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- 2019
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9. Pervasive Differential Splicing in Marek’s Disease Virus Can Discriminate CVI-988 Vaccine Strain from RB-1B Very Virulent Strain in Chicken Embryonic Fibroblasts
- Author
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Paolo Ribeca, Venugopal Nair, Yashar Sadigh, Abdessamad Tahiri-Alaoui, and Stephen J. Spatz
- Subjects
Gene Expression Regulation, Viral ,0301 basic medicine ,RNA Splicing ,viruses ,Viral pathogenesis ,030106 microbiology ,lcsh:QR1-502 ,Virulence ,Chick Embryo ,RNA splicing isoforms ,medicine.disease_cause ,Marek’s disease virus ,lcsh:Microbiology ,Article ,Herpesviridae ,Virus ,Cell Line ,Transcriptome ,transcriptomics ,03 medical and health sciences ,Species Specificity ,MDV strain CVI-988 ,Virology ,Marek Disease ,medicine ,Animals ,MDV strain RB-1B ,Marek's disease ,biology ,Gene Expression Profiling ,Computational Biology ,RNA ,Viral Vaccines ,Fibroblasts ,biology.organism_classification ,Mardivirus ,030104 developmental biology ,Infectious Diseases ,RNA splicing - Abstract
Marek&rsquo, s disease is a major scourge challenging poultry health worldwide. It is caused by the highly contagious Marek&rsquo, s disease virus (MDV), an alphaherpesvirus. Here, we showed that, similar to other members of its Herpesviridae family, MDV also presents a complex landscape of splicing events, most of which are uncharacterised and/or not annotated. Quite strikingly, and although the biological relevance of this fact is unknown, we found that a number of viral splicing isoforms are strain-specific, despite the close sequence similarity of the strains considered: very virulent RB-1B and vaccine CVI-988. We validated our findings by devising an assay that discriminated infections caused by the two strains in chicken embryonic fibroblasts on the basis of the presence of some RNA species. To our knowledge, this study is the first to accomplish such a result, emphasizing how relevant a comprehensive picture of the viral transcriptome is to fully understand viral pathogenesis.
- Published
- 2020
10. Production, quality control, stability, and potency of cGMP-produced
- Author
-
Jing, Jin, Richard D, Tarrant, Emma J, Bolam, Philip, Angell-Manning, Max, Soegaard, David J, Pattinson, Pawan, Dulal, Sarah E, Silk, Jennifer M, Marshall, Rebecca A, Dabbs, Fay L, Nugent, Jordan R, Barrett, Kathryn A, Hjerrild, Lars, Poulsen, Thomas, Jørgensen, Tanja, Brenner, Ioana N, Baleanu, Helena M, Parracho, Abdessamad, Tahiri-Alaoui, Gary, Whale, Sarah, Moyle, Ruth O, Payne, Angela M, Minassian, Matthew K, Higgins, Frank J, Detmers, Alison M, Lawrie, Alexander D, Douglas, Robert, Smith, Willem A, de Jongh, Eleanor, Berrie, Rebecca, Ashfield, and Simon J, Draper
- Subjects
Article - Abstract
Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) is a leading asexual blood-stage vaccine candidate for malaria. In preparation for clinical trials, a full-length PfRH5 protein vaccine called “RH5.1” was produced as a soluble product under cGMP using the ExpreS2 platform (based on a Drosophila melanogaster S2 stable cell line system). Following development of a high-producing monoclonal S2 cell line, a master cell bank was produced prior to the cGMP campaign. Culture supernatants were processed using C-tag affinity chromatography followed by size exclusion chromatography and virus-reduction filtration. The overall process yielded >400 mg highly pure RH5.1 protein. QC testing showed the MCB and the RH5.1 product met all specified acceptance criteria including those for sterility, purity, and identity. The RH5.1 vaccine product was stored at −80 °C and is stable for over 18 months. Characterization of the protein following formulation in the adjuvant system AS01B showed that RH5.1 is stable in the timeframe needed for clinical vaccine administration, and that there was no discernible impact on the liposomal formulation of AS01B following addition of RH5.1. Subsequent immunization of mice confirmed the RH5.1/AS01B vaccine was immunogenic and could induce functional growth inhibitory antibodies against blood-stage P. falciparum in vitro. The RH5.1/AS01B was judged suitable for use in humans and has since progressed to phase I/IIa clinical trial. Our data support the future use of the Drosophila S2 cell and C-tag platform technologies to enable cGMP-compliant biomanufacture of other novel and “difficult-to-express” recombinant protein-based vaccines., Malaria: Successful clinical trial preparation for blood-stage vaccine A vaccine candidate for blood-stage malaria has overcome previous hurdles to enter clinical trials. The protein PfRH5 is an essential blood-stage infection facilitator of malarial parasite Plasmodium falciparum, and a promising target for vaccine strategies. Unfortunately, efforts to produce the protein in an immunogenic, clinically-viable way have been met with difficulty. Here, researchers led by Simon Draper, from the UK’s Jenner Institute, used a fruit fly expression system to produce over 400 mg of high-purity protein. Formulated with an immunity-boosting adjuvant, the vaccine elicited antibodies in mice that proved inhibitory to blood-stage P. falciparum during in vitro assays. The PfRH5 vaccine candidate and its adjuvant have been approved for a clinical trial in the UK, and the authors hope that the expression system used may be beneficial in the expression of other ‘difficult’ proteins.
- Published
- 2018
11. Identification of a Neurovirulence Factor from Marek's Disease Virus
- Author
-
Lydia Kgosana, Lorraine P. Smith, Venugopal Nair, Lawrence Petherbridge, and Abdessamad Tahiri-Alaoui
- Subjects
Gene Expression Regulation, Viral ,RNA Caps ,Nervous system ,Transcription, Genetic ,Virulence Factors ,Chick Embryo ,Neuropathology ,Disease ,Nervous System ,Virus ,Immediate-Early Proteins ,Viral Proteins ,Food Animals ,Marek Disease ,medicine ,Animals ,RNA, Messenger ,Herpesvirus 2, Gallid ,Gene ,Cells, Cultured ,Poultry Diseases ,Marek's disease ,General Immunology and Microbiology ,biology ,biology.organism_classification ,Phenotype ,Virology ,Specific Pathogen-Free Organisms ,medicine.anatomical_structure ,Viral replication ,Animal Science and Zoology ,Chickens ,Gene Deletion - Abstract
In addition to tumors, Marek's disease (MD) virus (MDV) can induce a variety of syndromes linked to the central nervous system. In fact, early descriptions of MD suggested that it was a condition affecting mainly the nervous system. Cytokines and other immune-related genes have been suggested to play a crucial role in MDV-mediated neuropathology, but the mechanisms behind the viral-induced neurologic dysfunction are still poorly understood. In the present study we have used reverse genetic strategies to show that pp14 is not involved in the oncogenic phenotype of MDV1 and is not required for viral replication; however, we provide evidence indicating that the absence of pp14 expression is correlated with increased survival of MDV1-infected chickens, and that its expression is associated with enhanced viral neurovirulence. Our data identify for the first time pp14 as a neurovirulence factor from MDV1 and open the possibility to investigate the molecular mechanisms by which pp14 mediates the damage to the avian nervous system.
- Published
- 2013
12. Identification of an intercistronic internal ribosome entry site in a Marek's disease virus immediate-early gene
- Author
-
Venugopal Nair, Abdessamad Tahiri-Alaoui, Lawrence Petherbridge, Lydia Kgosana, Suzan Baigent, William James, Lorraine P. Smith, and Luke S. Lambeth
- Subjects
Gene Expression Regulation, Viral ,Transcription, Genetic ,Mardivirus ,animal diseases ,viruses ,Immunology ,Genome, Viral ,Microbiology ,Immediate early protein ,Cell Line ,Immediate-Early Proteins ,Exon ,Virology ,Marek Disease ,Animals ,ORFS ,Gene ,Genetics ,Marek's disease ,biology ,fungi ,virus diseases ,biology.organism_classification ,Genome Replication and Regulation of Viral Gene Expression ,Open reading frame ,Internal ribosome entry site ,Insect Science ,DNA, Intergenic ,Chickens ,Ribosomes ,Gene Deletion - Abstract
In this study, we have identified an internal ribosome entry site (IRES) from the highly infectious herpesvirus Marek's disease virus (MDV). The IRES was mapped to the intercistronic region (ICR) of a bicistronic mRNA that we cloned from the MDV-transformed CD4 + T-cell line MSB-1. The transcript is a member of a family of mRNAs expressed as immediate-early genes with two open reading frames (ORF). The first ORF encodes a 14-kDa polypeptide with two N-terminal splice variants, whereas the second ORF is contained entirely within a single exon and encodes a 12-kDa protein also known as RLORF9. We have shown that the ICR that separates the two ORFs functions as an IRES that controls the translation of RLORF9 when cap-dependent translation is inhibited. Deletion analysis revealed that there are two potential IRES elements within the ICR. Reverse genetic experiments with the oncogenic strain of MDV type 1 indicated that deletion of IRES-controlled RLORF9 does not significantly affect viral replication or MDV-induced mortality.
- Published
- 2016
13. Heterologous amyloid seeding: revisiting the role of acetylcholinesterase in Alzheimer's disease
- Author
-
Michael Shaw, Benjamin Thomas, David J. Vaux, Létitia Jean, and Abdessamad Tahiri-Alaoui
- Subjects
Proteases ,Amyloid ,Protein Conformation ,Proteolysis ,Molecular Sequence Data ,Biophysics ,lcsh:Medicine ,Insulysin ,Biochemistry ,Prion Diseases ,03 medical and health sciences ,0302 clinical medicine ,Alzheimer Disease ,mental disorders ,medicine ,Pathology ,Humans ,Amino Acid Sequence ,lcsh:Science ,Neprilysin ,030304 developmental biology ,Aged ,Biochemistry/Experimental Biophysical Methods ,0303 health sciences ,Multidisciplinary ,Amyloid beta-Peptides ,biology ,medicine.diagnostic_test ,Chromosomes, Human, Pair 10 ,Neurodegeneration ,lcsh:R ,P3 peptide ,Chromosome Mapping ,Parkinson Disease ,medicine.disease ,Peptide Fragments ,Huntington Disease ,biology.protein ,Acetylcholinesterase ,lcsh:Q ,Alzheimer's disease ,Amyloid Precursor Protein Secretases ,Amyloid precursor protein secretase ,Neurological Disorders/Alzheimer Disease ,030217 neurology & neurosurgery ,Research Article - Abstract
Neurodegenerative diseases associated with abnormal protein folding and ordered aggregation require an initial trigger which may be infectious, inherited, post-inflammatory or idiopathic. Proteolytic cleavage to generate vulnerable precursors, such as amyloid-beta peptide (Abeta) production via beta and gamma secretases in Alzheimer's Disease (AD), is one such trigger, but the proteolytic removal of these fragments is also aetiologically important. The levels of Abeta in the central nervous system are regulated by several catabolic proteases, including insulysin (IDE) and neprilysin (NEP). The known association of human acetylcholinesterase (hAChE) with pathological aggregates in AD together with its ability to increase Abeta fibrilization prompted us to search for proteolytic triggers that could enhance this process. The hAChE C-terminal domain (T40, AChE(575-614)) is an exposed amphiphilic alpha-helix involved in enzyme oligomerisation, but it also contains a conformational switch region (CSR) with high propensity for conversion to non-native (hidden) beta-strand, a property associated with amyloidogenicity. A synthetic peptide (AChE(586-599)) encompassing the CSR region shares homology with Abeta and forms beta-sheet amyloid fibrils. We investigated the influence of IDE and NEP proteolysis on the formation and degradation of relevant hAChE beta-sheet species. By combining reverse-phase HPLC and mass spectrometry, we established that the enzyme digestion profiles on T40 versus AChE(586-599), or versus Abeta, differed. Moreover, IDE digestion of T40 triggered the conformational switch from alpha- to beta-structures, resulting in surfactant CSR species that self-assembled into amyloid fibril precursors (oligomers). Crucially, these CSR species significantly increased Abeta fibril formation both by seeding the energetically unfavorable formation of amyloid nuclei and by enhancing the rate of amyloid elongation. Hence, these results may offer an explanation for observations that implicate hAChE in the extent of Abeta deposition in the brain. Furthermore, this process of heterologous amyloid seeding by a proteolytic fragment from another protein may represent a previously underestimated pathological trigger, implying that the abundance of the major amyloidogenic species (Abeta in AD, for example) may not be the only important factor in neurodegeneration.
- Published
- 2016
14. Autocatalytic RNA cleavage in the human beta-globin pre-mRNA promotes transcription termination
- Author
-
Steve West, Alexandre Akoulitchev, Nick J. Proudfoot, Igor Martianov, Abdessamad Tahiri-Alaoui, William James, Alexandre Teixeira, Aroul Ramadass, Benjamin Thomas, and Mick Dye
- Subjects
Genetics ,Messenger RNA ,Multidisciplinary ,biology ,Termination factor ,fungi ,Ribozyme ,RNA ,RNA polymerase II ,Cell biology ,Terminator (genetics) ,Transcription (biology) ,biology.protein ,RNA Cleavage - Abstract
New evidence indicates that termination of transcription is an important regulatory step, closely related to transcriptional interference and even transcriptional initiation. However, how this occurs is poorly understood. Recently, in vivo analysis of transcriptional termination for the human beta-globin gene revealed a new phenomenon--co-transcriptional cleavage (CoTC). This primary cleavage event within beta-globin pre-messenger RNA, downstream of the poly(A) site, is critical for efficient transcriptional termination by RNA polymerase II. Here we show that the CoTC process in the human beta-globin gene involves an RNA self-cleaving activity. We characterize the autocatalytic core of the CoTC ribozyme and show its functional role in efficient termination in vivo. The identified core CoTC is highly conserved in the 3' flanking regions of other primate beta-globin genes. Functionally, it resembles the 3' processive, self-cleaving ribozymes described for the protein-encoding genes from the myxomycetes Didymium iridis and Physarum polycephalum, indicating evolutionary conservation of this molecular process. We predict that regulated autocatalytic cleavage elements within pre-mRNAs may be a general phenomenon and that functionally it may provide the entry point for exonucleases involved in mRNA maturation, turnover and, in particular, transcriptional termination.
- Published
- 2016
15. Oligomerization of the human prion protein proceeds via a molten globule intermediate
- Author
-
Abdessamad Tahiri-Alaoui, Remo Gerber, William James, and P. J. Hore
- Subjects
Gene isoform ,Amyloid ,Protein Folding ,Magnetic Resonance Spectroscopy ,Chemistry ,Prions ,Protein Conformation ,Protein subunit ,Cell Biology ,Nuclear magnetic resonance spectroscopy ,Biochemistry ,Molten globule ,Protein Structure, Secondary ,chemistry.chemical_compound ,Protein structure ,Monomer ,Biophysics ,Humans ,Protein folding ,Molecular Biology ,Dimerization - Abstract
The conformational transition of the human prion protein from an alpha-helical to a beta-sheet-rich structure is believed to be the critical event in prion pathogenesis. The molecular mechanism of misfolding and the role of intermediate states during this transition remain poorly understood. To overcome the obstacle of insolubility of amyloid fibrils, we have studied a beta-sheet-rich misfolded isoform of the prion protein, the beta-oligomer, which shares some structural properties with amyloid, including partial proteinase resistance. We demonstrate here that the beta-oligomer can be studied by solution-state NMR spectroscopy and obtain insights into the misfolding mechanism via its transient monomeric precursor. It is often assumed that misfolding into beta-sheet-rich isoforms proceeds via a compatible precursor with a beta-sheet subunit structure. We show here, on the contrary, evidence for an almost natively alpha-helix-rich monomeric precursor state with molten globule characteristics, converting in vitro into the beta-oligomer. We propose a possible mechanism for the formation of the beta-oligomer, triggered by intermolecular contacts between constantly rearranging structures. It is concluded that the beta-oligomer is not preceded by precursors with beta-sheet structure but by a partially unfolded clearly distinguishable alpha-helical state.
- Published
- 2016
16. Inter-oligomer interactions of the human prion protein are modulated by the polymorphism at codon 129
- Author
-
Remo Gerber, Kislon Voïtchovsky, Clement Mitchel, John F. Ryan, P. J. Hore, William James, and Abdessamad Tahiri-Alaoui
- Subjects
Protein Denaturation ,Polymorphism, Genetic ,Prions ,Atomic force microscopy ,Circular Dichroism ,Stacking ,Microscopy, Atomic Force ,Oligomer ,chemistry.chemical_compound ,chemistry ,Polymorphism (materials science) ,Biochemistry ,Structural Biology ,Valine ,Biophysics ,Humans ,Prion protein ,Allele ,Codon ,Nuclear Magnetic Resonance, Biomolecular ,Molecular Biology ,Chromatography, High Pressure Liquid ,Heteronuclear single quantum coherence spectroscopy ,Protein Binding - Abstract
The common polymorphism at codon 129 in the human prion protein (PrP) has been shown in many studies to influence not only the pathology of prion disease but also the misfolding propensity of PrP. Here we used NMR, CD and atomic force microscopy in solution to investigate differences in beta-oligomer (beta(O)) formation and inter-oligomer interaction depending on the polymorphism at codon 129. NMR investigations assigned the observable amide resonances to the beta(O) N-terminal segments, showing that it is the core region of PrP (residues 127-228) that is involved in beta(O) formation. Atomic force microscopy revealed distinctive 1.8 x 15 x 15-nm disk-like structures that form stacks through inter-oligomer interactions. The propensity to form stacks and the number of oligomers involved depended on the polymorphism at codon 129, with a significantly lower degree of stacking for beta(O) with valine at position 129. This result provides evidence for conformational differences between the beta(O) allelic forms, showing that the core region of the protein including position 129 is actively involved in inter-oligomer interactions, consistent with NMR observations.
- Published
- 2016
17. The 5' leader of the mRNA encoding the marek's disease virus serotype 1 pp14 protein contains an intronic internal ribosome entry site with allosteric properties
- Author
-
Luke S. Lambeth, Panopoulos Panagiotis, William James, Luke Burman, Hongtao Xu, Lawrence Petherbridge, Daiki Matsuda, Abdessamad Tahiri-Alaoui, Vincent P. Mauro, and Venugopal Nair
- Subjects
RNA Caps ,Immunology ,Microbiology ,Ribosome ,Viral Proteins ,Allosteric Regulation ,Virology ,Animals ,RNA, Messenger ,Codon ,Herpesvirus 2, Gallid ,Gene ,Cells, Cultured ,Genetics ,Marek's disease ,Messenger RNA ,biology ,fungi ,Alternative splicing ,Intron ,biology.organism_classification ,Introns ,Genome Replication and Regulation of Viral Gene Expression ,Internal ribosome entry site ,Open reading frame ,Genes ,Insect Science ,5' Untranslated Regions ,Ribosomes - Abstract
We demonstrate the presence of a functional internal ribosome entry site (IRES) within the 5′ leader (designated 5L) from a variant of bicistronic mRNAs that encode the pp14 and RLORF9 proteins from Marek's disease virus (MDV) serotype 1. Transcribed as a 1.8-kb family of immediate-early genes, the mature bicistronic mRNAs have variable 5′ leader sequences due to alternative splicing or promoter usage. Consequently, the presence or absence of the 5L IRES in the mRNA dictates the mode of pp14 translation and leads to the production of two pp14 isoforms that differ in their N-terminal sequences. Real-time reverse transcription-quantitative PCR indicates that the mRNA variants with the 5L IRES is two to three times more abundant in MDV-infected and transformed cells than the mRNA variants lacking the 5L IRES. A common feature to all members of the 1.8-kb family of transcripts is the presence of an intercistronic IRES that we have previously shown to control the translation of the second open reading frame (i.e., RLORF9). Investigation of the two IRESs residing in the same bicistronic reporter mRNA revealed functional synergism for translation efficiency. In analogy with allosteric models in proteins, we propose IRES allostery to describe such a novel phenomenon. The functional implications of our findings are discussed in relation to host-virus interactions and translational control.
- Published
- 2016
18. Molecular Heterosis of Prion Protein β-Oligomers
- Author
-
Valerie L. Sim, William James, Abdessamad Tahiri-Alaoui, and Byron Caughey
- Subjects
Genetics ,education.field_of_study ,Amyloid ,Population ,Heterozygote advantage ,Cell Biology ,Biology ,Balancing selection ,Biochemistry ,Fungal prion ,Polymorphism (computer science) ,Allele ,education ,Molecular Biology ,Gene - Abstract
The gene encoding prion protein is polymorphic in human populations, with over 40% of native Europeans, for example, being heterozygous for the Met-129 and Val-129 alleles. The polymorphism affects both the incidence and the clinical presentation of a range of prion diseases, with heterozygotes generally showing the highest levels of resistance. It has been suggested that an earlier epidemic of prion diseases exerted balancing selection on the two alleles, and we have previously demonstrated that the two encoded proteins have potentially compensating tendencies to form amyloid and soluble β-oligomers, respectively, in vitro. More strikingly, here we demonstrate that mixed oligomers, composed of both allelic forms, show an extreme sluggishness in converting to amyloid in comparison with oligomers homogenous for either allele. It may be that this example of molecular heterosis in vitro provides the basis for maintenance of the polymorphism in the population and that β-oligomers represent a form of PrP sequestered from pathogenic amyloid formation in vivo.
- Published
- 2006
19. Characterization of 2′-Fluoro-RNA Aptamers That Bind Preferentially to Disease-associated Conformations of Prion Protein and Inhibit Conversion
- Author
-
Andrew C. Gill, Petra Disterer, I. Sylvester, Abdessamad Tahiri-Alaoui, James Hope, Natalie M. Sayer, Alexandre G. O. Rhie, William James, Louise Kirby, and Rosanna Wellesley
- Subjects
Prions ,Protein Conformation ,animal diseases ,Aptamer ,In Vitro Techniques ,Biology ,Ligands ,Biochemistry ,Protein Structure, Secondary ,Prion Diseases ,law.invention ,Protein structure ,law ,Sequence Homology, Nucleic Acid ,Animals ,Binding site ,Molecular Biology ,Binding Sites ,Oligoribonucleotides ,Base Sequence ,Ligand ,RNA ,Cell Biology ,Molecular biology ,C760 Biomolecular Science ,In vitro ,nervous system diseases ,Nucleic acid ,Recombinant DNA ,Cattle - Abstract
We have isolated artificial ligands or aptamers for infectious prions in order to investigate conformational aspects of prion pathogenesis. The aptamers are 2'-fluoro-modified RNA produced by in vitro selection from a large, randomized library. One of these ligands (aptamer SAF-93) had more than 10-fold higher affinity for PrPSc than for recombinant PrPC and inhibited the accumulation of PrPres in near physiological cell-free conversion assay. To understand the molecular basis of these properties and to distinguish specific from non-specific aptamer-PrP interactions, we studied deletion mutants of bovine PrP in denatured, alpha-helix-rich and beta-sheet-rich forms. We provide evidence that, like scrapie-associated fibrils (SAF), the beta-oligomer of PrP bound to SAF-93 with at least 10-fold higher affinity than did the alpha-form. This differential affinity could be explained by the existence of two binding sites within the PrP molecule. Site 1 lies within residues 23-110 in the unstructured N terminus and is a nonspecific RNA binding site found in all forms of PrP. The region between residue 90 and 110 forms a hinge region that is occluded in the alpha-rich form of PrP but becomes exposed in the denatured form of PrP. Site 2 lies in the region C-terminal of residue 110. This site is beta-sheet conformation-specific and is not recognized by control RNAs. Taken together, these data provide for the first time a specific ligand for a disease conformation-associated site in a region of PrP critical for conformational conversion. This aptamer could provide tools for the further analysis of the processes of PrP misfolding during prion disease and leads for the development of diagnostic and therapeutic approaches to TSEs.
- Published
- 2003
20. Competing intrachain interactions regulate the formation of beta-sheet fibrils in bovine PrP peptides
- Author
-
Abdessamad Tahiri-Alaoui, William James, Mario Bouchard, and Jesús Zurdo
- Subjects
Spectrophotometry, Infrared ,Protein Conformation ,animal diseases ,Beta sheet ,Scrapie ,Peptide ,Fibril ,Biochemistry ,Article ,Protein structure ,Cricetinae ,Animals ,Humans ,PrPC Proteins ,Molecular Biology ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,Circular Dichroism ,Fibrillogenesis ,Peptide Fragments ,PrP 27-30 Protein ,nervous system diseases ,Cell biology ,Microscopy, Electron ,chemistry ,Cattle ,Glycoprotein - Abstract
At the heart of the pathogenesis of transmissible spongiform encephalopathies (TSEs), such as BSE, scrapie, and Creutzfeldt-Jakob disease, lies a poorly understood structural rearrangement of PrP, an abundant glycoprotein of the nervous and lymphoid systems. The normal form (PrP(C)), rich in alpha-helix, converts into an aberrant beta-sheet-dominated form (PrP(Sc)), which seems to be at the center of the pathotoxic symptoms observed in TSEs. To understand this process better at a molecular level, we have studied the interactions between different peptides derived from bovine PrP and their structural significance. We show that two unstructured peptides derived from the central region of bovine PrP, residues 115-133 and 140-152, respectively, interact stoichiometrically under physiological conditions to generate beta-sheet-dominated fibrils. However, when both peptides are incubated in the presence of a third peptide derived from an adjoining alpha-helical region (residues 153-169), the formation of beta-sheet-rich fibrils is abolished. These data indicate that native PrP(C) helix 1 might inhibit the strong intrinsic beta-sheet-forming propensity of sequences immediately N-terminal to the globular core of PrP(C), by keeping in place intrachain interactions that would prevent these amyloidogenic regions from triggering aggregation. Moreover, these results indicate new ways in which PrP(Sc) formation could be prevented.
- Published
- 2003
21. Conformational pH dependence of intermediate states during oligomerization of the human prion protein
- Author
-
Remo Gerber, P. J. Hore, Abdessamad Tahiri-Alaoui, and William James
- Subjects
Protein Folding ,Prions ,Nuclear magnetic resonance spectroscopy ,Hydrogen-Ion Concentration ,Biochemistry ,Oligomer ,Molten globule ,Protein tertiary structure ,Protein Structure, Secondary ,Article ,Protein Structure, Tertiary ,chemistry.chemical_compound ,Crystallography ,Monomer ,chemistry ,Biophysics ,Intermediate state ,Humans ,Protein folding ,Codon ,Molecular Biology ,Protein secondary structure ,Nuclear Magnetic Resonance, Biomolecular - Abstract
Intermediate states are key to understanding the molecular mechanisms governing protein misfolding. The human prion protein (PrP) can follow various misfolding pathways, and forms a soluble beta-sheet-rich oligomer under acidic, mildly denaturing, high salt conditions. Here we describe a fast conformational switch from the native alpha-monomer to monomeric intermediate states under oligomer-forming conditions, followed by a slower oligomerization process. We observe a pH dependence of the secondary structure of these intermediate forms, with almost native-like alpha-helical secondary structure at pH 4.1 and predominantly beta-sheet characteristics at pH 3.6. NMR spectroscopy differentiates these intermediate states from the native protein and indicates dynamic rearrangements of secondary structure elements characteristic of a molten globule. The alpha-helical intermediate formed at pH 4.1 can convert to the beta-sheet conformation at pH 3.6 but not vice versa, and neither state can be reconverted to an alpha-monomer. The presence of methionine rather than valine at codon 129 accelerates the rate of oligomer formation from the intermediate state.
- Published
- 2008
22. Molecular heterosis of prion protein beta-oligomers. A potential mechanism of human resistance to disease
- Author
-
Abdessamad, Tahiri-Alaoui, Valerie L, Sim, Byron, Caughey, and William, James
- Subjects
Amyloid ,Heterozygote ,Prions ,Circular Dichroism ,Homozygote ,Valine ,Prion Diseases ,Kinetics ,Thiazoles ,Methionine ,Hybrid Vigor ,Humans ,Benzothiazoles ,Alleles - Abstract
The gene encoding prion protein is polymorphic in human populations, with over 40% of native Europeans, for example, being heterozygous for the Met-129 and Val-129 alleles. The polymorphism affects both the incidence and the clinical presentation of a range of prion diseases, with heterozygotes generally showing the highest levels of resistance. It has been suggested that an earlier epidemic of prion diseases exerted balancing selection on the two alleles, and we have previously demonstrated that the two encoded proteins have potentially compensating tendencies to form amyloid and soluble beta-oligomers, respectively, in vitro. More strikingly, here we demonstrate that mixed oligomers, composed of both allelic forms, show an extreme sluggishness in converting to amyloid in comparison with oligomers homogenous for either allele. It may be that this example of molecular heterosis in vitro provides the basis for maintenance of the polymorphism in the population and that beta-oligomers represent a form of PrP sequestered from pathogenic amyloid formation in vivo.
- Published
- 2006
23. Poly(A) Binding Protein 1 Enhances Cap-Independent Translation Initiation of Neurovirulence Factor from Avian Herpesvirus
- Author
-
Venugopal Nair, Abdessamad Tahiri-Alaoui, Lydia Kgosana, Lorraine P. Smith, James Popplestone, Yuguang Zhao, and Yashar Sadigh
- Subjects
Virulence Factors ,Molecular Sequence Data ,lcsh:Medicine ,RNA-binding protein ,Biochemistry ,Microbiology ,Poly(A)-Binding Protein I ,Cell Line ,Viral Proteins ,03 medical and health sciences ,Eukaryotic translation ,Poly(A)-binding protein ,Animals ,Humans ,RNA, Messenger ,lcsh:Science ,Peptide Chain Initiation, Translational ,Molecular Biology ,Herpesvirus 2, Gallid ,030304 developmental biology ,0303 health sciences ,Messenger RNA ,Multidisciplinary ,Base Sequence ,biology ,Binding protein ,lcsh:R ,030302 biochemistry & molecular biology ,Biology and Life Sciences ,RNA-Binding Proteins ,RNA ,Cell Biology ,Molecular biology ,3. Good health ,Cell biology ,MicroRNAs ,Protein Transport ,Internal ribosome entry site ,Gene Expression Regulation ,Mutagenesis ,Mutation ,biology.protein ,lcsh:Q ,Poly A ,Chickens ,Research Article ,Neuroscience - Abstract
Poly(A) binding protein 1 (PABP1) plays a central role in mRNA translation and stability and is a target by many viruses in diverse manners. We report a novel viral translational control strategy involving the recruitment of PABP1 to the 5' leader internal ribosome entry site (5L IRES) of an immediate-early (IE) bicistronic mRNA that encodes the neurovirulence protein (pp14) from the avian herpesvirus Marek's disease virus serotype 1 (MDV1). We provide evidence for the interaction between an internal poly(A) sequence within the 5L IRES and PABP1 which may occur concomitantly with the recruitment of PABP1 to the poly(A) tail. RNA interference and reverse genetic mutagenesis results show that a subset of virally encoded-microRNAs (miRNAs) targets the inhibitor of PABP1, known as paip2, and therefore plays an indirect role in PABP1 recruitment strategy by increasing the available pool of active PABP1. We propose a model that may offer a mechanistic explanation for the cap-independent enhancement of the activity of the 5L IRES by recruitment of a bona fide initiation protein to the 5' end of the message and that is, from the affinity binding data, still compatible with the formation of 'closed loop' structure of mRNA.
- Published
- 2014
24. The presence of valine at residue 129 in human prion protein accelerates amyloid formation
- Author
-
Petra Disterer, Andrew C. Gill, William James, Abdessamad Tahiri-Alaoui, Leonid Breydo, Ilia V. Baskakov, and Michael Shaw
- Subjects
Amyloid ,Protein Folding ,Prions ,Protein Conformation ,Biophysics ,Biology ,Biochemistry ,Models, Biological ,Protein Structure, Secondary ,law.invention ,chemistry.chemical_compound ,Protein structure ,Methionine ,Codon 129 ,Structural Biology ,Valine ,law ,Spectroscopy, Fourier Transform Infrared ,Genetics ,Humans ,Polymorphism ,Codon ,Molecular Biology ,Gene ,Alleles ,Chromatography, High Pressure Liquid ,Polymorphism, Genetic ,Circular Dichroism ,Genetic Variation ,Folding ,Cell Biology ,In vitro ,Recombinant Proteins ,Kinetics ,chemistry ,Recombinant DNA ,Protein folding - Abstract
The polymorphism at residue 129 of the human PRNP gene modulates disease susceptibility and the clinicopathological phenotypes in human transmissible spongiform encephalopathies. The molecular mechanisms by which the effect of this polymorphism are mediated remain unclear. It has been shown that the folding, dynamics and stability of the physiological, alpha-helix-rich form of recombinant PrP are not affected by codon 129 polymorphism. Consistent with this, we have recently shown that the kinetics of amyloid formation do not differ between protein containing methionine at codon 129 and valine at codon 129 when the reaction is initiated from the a-monomeric PrPC-like state. In contrast, we have shown that the misfolding pathway leading to the formation of beta-sheet-rich, soluble oligomer waS favoured by the presence of methionine, compared with valine, at position 129. In the present work, we examine the effect of this polymorphism on the kinetics of an alternative misfolding pathway, that of amyloid formation using partially folded PrP allelomorphs. We show that the valine 129 allelomorph forms amyloids with a considerably shorter lag phase than the methionine 129 allelomorph both under spontaneous conditions and when seeded with pre-formed amyloid fibres. Taken together, our studies demonstrate that the effect of the codon 129 polymorphism depends on the specific misfolding pathway and on the initial conformation of the protein. The inverse propensities of the two allelomorphs to misfold in vitro through the alternative oligomeric and amyloidogenic pathways could explain some aspects of prion diseases linked to this polymorphism such as age at onset and disease incubation time. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
- Published
- 2005
25. Rapid formation of amyloid from alpha-monomeric recombinant human PrP in vitro
- Author
-
Abdessamad Tahiri-Alaoui and William James
- Subjects
Amyloid ,Protein Folding ,Prions ,animal diseases ,Context (language use) ,Biology ,Biochemistry ,Article ,law.invention ,In vivo ,law ,mental disorders ,Amyloid precursor protein ,Humans ,Molecular Biology ,chemistry.chemical_classification ,Polymorphism, Genetic ,Molecular biology ,Recombinant Proteins ,In vitro ,Cell biology ,nervous system diseases ,Kinetics ,chemistry ,Recombinant DNA ,biology.protein ,Protein folding ,Glycoprotein - Abstract
The infectious agent of prion diseases is identified with PrP(Sc), a beta-rich, amyloidogenic and partially protease resistant isoform of the cellular glycoprotein, PrP(C). To understand the process of prion formation in vivo, we and others have studied defined misfolding pathways of recombinant PrP in vitro. The low-level infectivity of the in vitro misfolded murine PrP amyloid has recently been reported. Here we analyze the in vitro kinetics of amyloid formation from recombinant human PrP(90-231) in vitro in the context of two common allelic forms of PrP found in human populations that are associated with differences in prion disease susceptibility and pathological phenotype. We show that human PrP amyloid forms readily from its PrP(C)-like state in vitro, that the lag time of the reaction can be further shortened by the presence of a "seed" of pre-formed PrP amyloid, and that amyloid propagation is more complex than a simple crystallization process. We further show that the kinetics of amyloid formation do not differ between the Met129 and Val129 allelomorphs of human PrP, and that amyloid from each functions as an equally effective seed in heterologous, as in homologous amyloid reactions. The results could illuminate the process of amyloid formation in vivo as well as help understanding prion pathogenesis.
- Published
- 2005
26. Methionine 129 variant of human prion protein oligomerizes more rapidly than the valine 129 variant: implications for disease susceptibility to Creutzfeldt-Jakob disease
- Author
-
Abdessamad, Tahiri-Alaoui, Andrew C, Gill, Petra, Disterer, and William, James
- Subjects
Models, Molecular ,Heterozygote ,Protein Folding ,Prions ,Homozygote ,Molecular Sequence Data ,Genetic Variation ,Valine ,In Vitro Techniques ,Creutzfeldt-Jakob Syndrome ,Protein Structure, Secondary ,Recombinant Proteins ,Methionine ,Humans ,Amino Acid Sequence ,Endopeptidase K ,Protein Structure, Quaternary ,Alleles - Abstract
The human PrP gene (PRNP) has two common alleles that encode either methionine or valine at codon 129. This polymorphism modulates disease susceptibility and phenotype of human transmissible spongiform encyphalopathies, but the molecular mechanism by which these effects are mediated remains unclear. Here, we compared the misfolding pathway that leads to the formation of beta-sheet-rich oligomeric isoforms of the methionine 129 variant of PrP to that of the valine 129 variant. We provide evidence for differences in the folding behavior between the two variants at the early stages of oligomer formation. We show that Met(129) has a higher propensity to form beta-sheet-rich oligomers, whereas Val(129) has a higher tendency to fold into alpha-helical-rich monomers. An equimolar mixture of both variants displayed an intermidate folding behavior. We show that the oligomers of both variants are initially a mixture of alpha- and beta-rich conformers that evolve with time to an increasingly homogeneous beta-rich form. This maturation process, which involves no further change in proteinase K resistance, occurs more rapidly in the Met(129) form than the Val(129) form. Although the involvement of such beta-rich oligomers in prion pathogenesis is speculative, the misfolding behavior could, in part, explain the higher susceptibility of individuals that are methionine homozygote to both sporadic and variant Creutzfeldt-Jakob disease.
- Published
- 2004
27. Structural determinants of conformationally selective, prion-binding aptamers
- Author
-
Alexandre G. O. Rhie, Abdessamad Tahiri-Alaoui, Marc Bullock, Matthew Cubin, William James, and Natalie M. Sayer
- Subjects
Protein Folding ,Transcription, Genetic ,Prions ,Protein Conformation ,Aptamer ,animal diseases ,Molecular Sequence Data ,Plasma protein binding ,Biology ,Biochemistry ,Protein Structure, Secondary ,Protein structure ,Escherichia coli ,Animals ,Urea ,Biotinylation ,Binding site ,Molecular Biology ,Binding selectivity ,Binding Sites ,Base Sequence ,Dose-Response Relationship, Drug ,Cell Biology ,Molecular biology ,In vitro ,nervous system diseases ,Kinetics ,RNA ,Cattle ,Electrophoresis, Polyacrylamide Gel ,Protein folding ,Protein Binding - Abstract
We have recently described the isolation of 2'-fluoropyrimidine-substituted RNA aptamers that bind selectively to disease-associated beta-sheet-rich forms of the prion protein, PrP, from a number of mammalian species. These aptamers inhibit the accumulation of protease-resistant forms of PrP in a prion-seeded, in vitro conversion assay. Here we identify the minimal portions of two of these aptamers that retain binding specificity. We determine their secondary structures by a combination of modeling and solution probing. Finally, we identify an internal site for biotinylation of a minimized, synthetic aptamer and use the resultant reagent in the detection of abnormal forms of PrP in vitro.
- Published
- 2004
28. Structural characterization of a 2'F-RNA aptamer that binds a HIV-1 SU glycoprotein, gp120
- Author
-
K. Turner, Natalie M. Sayer, William James, Jamal Ibrahim, and Abdessamad Tahiri-Alaoui
- Subjects
Anti-HIV Agents ,Aptamer ,Molecular Sequence Data ,Biophysics ,DNA Footprinting ,Sequence alignment ,Biology ,HIV Envelope Protein gp120 ,Biochemistry ,Epitope ,Cricetinae ,Tumor Cells, Cultured ,Animals ,Binding site ,Nucleic acid structure ,Molecular Biology ,chemistry.chemical_classification ,Binding Sites ,Oligoribonucleotides ,Base Sequence ,RNA ,Cell Biology ,Molecular biology ,Kinetics ,chemistry ,HIV-1 ,Nucleic Acid Conformation ,Target protein ,Glycoprotein ,Sequence Alignment - Abstract
Here we describe the isolation of specific 2'F-substituted RNA ligands for the SU glycoprotein, gp120, of HIV-1 strain HXB2. These aptamers bind the target protein with an affinity of the order of 10(-7) M. Binding was specific to SU glycoprotein and directed to a non-neutralizing epitope that was not shared with the related strain, HIV-1(BaL). The structure of one aptamer was defined by a combination of deletion analysis and enzymatic probing studies, revealing a 42 nt minimal element comprising a three-helix junction that retained the binding affinity of the parental sequence. Interestingly, binding to SU glycoprotein was accompanied by structural changes in the aptamer that stabilized the weakest of the 3 helices.
- Published
- 2002
29. High affinity nucleic acid aptamers for streptavidin incorporated into bi-specific capture ligands
- Author
-
Pascale Romby, Laura Frigotto, Jamal Ibrahim, Abdessamad Tahiri-Alaoui, William James, and Nick Manville
- Subjects
Streptavidin ,Aptamer ,Affinity label ,Molecular Sequence Data ,Oligonucleotides ,Electrophoretic Mobility Shift Assay ,Ligands ,Binding, Competitive ,chemistry.chemical_compound ,Genetics ,Binding site ,Protein secondary structure ,NAR Methods Online ,Binding Sites ,Base Sequence ,biology ,Oligonucleotide ,Affinity Labels ,Combinatorial chemistry ,Footprinting ,chemistry ,Biochemistry ,Nucleic acid ,biology.protein ,Nucleic Acid Conformation ,RNA - Abstract
We have isolated 2'-Fluoro-substituted RNA aptamers that bind to streptavidin (SA) with an affinity around 7 +/- 1.8 nM, comparable with that of recently described peptide aptamers. Binding to SA was not prevented by prior saturation with biotin, enabling nucleic acid aptamers to form useful ternary complexes. Mutagenesis, secondary structure analysis, ribonuclease footprinting and deletion analysis provided evidence for the essential structural features of SA-binding aptamers. In order to provide a general method for the exploitation of these aptamers, we produced derivatives in which they were fused to the naturally structured RNA elements, CopT or CopA. In parallel, we produced derivatives of CD4-binding aptamers fused to the complementary CopA or CopT elements. When mixed, these two chimeric aptamers rapidly hybridized, by virtue of CopA-CopT complementarity, to form stable, bi-functional aptamers that we called 'adaptamers'. We show that a CD4-SA-binding adaptamer can be used to capture CD4 onto a SA-derivatized surface, illustrating their general utility as indirect affinity ligands.
- Published
- 2002
30. Expression of the PR-b1' gene in the roots of two Nicotiana species and their amphidiploid hybrid infected with virulent and avirulent races of Chalara elegans
- Author
-
Silvio Gianinazzi, John F. Antoniw, Abdessamad Tahiri-Alaoui, and Eliane Dumas-Gaudot
- Subjects
0106 biological sciences ,Genetics ,0303 health sciences ,biology ,Nicotiana tabacum ,fungi ,Plant Sciences ,Virulence ,food and beverages ,Plant Science ,Fungi imperfecti ,Horticulture ,Pathogenic fungus ,biology.organism_classification ,01 natural sciences ,Agronomy ,03 medical and health sciences ,Root rot ,Nicotiana glutinosa ,Agronomy and Crop Science ,030304 developmental biology ,010606 plant biology & botany ,Nicotiana ,Pathogenesis-related protein - Abstract
We have previously reported the production of the three main groups of PR-protein in roots of a moderately resistant Nicotiana tabacum cv Xanthi nc. infected by the black root rot fungus Chalara elegans. In this work we have investigated changes in PR-bl gene expression in roots of two Nicotiana species, N. debneyi, N. glutinosa and their amphidiploid hybrid N. glutinosa X N. debneyi in response to the infection by two isolates of C. elegans, 85-26 and 84-1 which are respectively avirulent and virulent races. N. debneyi is highly resistant toward C. elegans, its resistance has been reported to be of monogenic inheritance, while N. glutinosa is a susceptible one. The amphidiploid hybrid N. glutinosa X N. debneyi is also highly resistant to C. elegans. It has been shown that PR-b1″ is the only PR-1 protein produced by these plants and that it is expressed constitutively in the hybrid. The PR-b1″ is induced in either of the two parent plants only after the hypersensitive reaction to viruses infection or chemical treatments. We report here a correlation between the infection rate of Nicotiana roots by the pathogenic fungus C. elegans and the relative level of PR-b1″ gene expression in the two parent plants. Irrespective of whether the plant is susceptible or resistant and whether the fungal race is virulent or avirulent, the results obtained showed that, low infection rates induce low levels of PR-b1″ mRNA as seen in N. debneyi infected with avirulent race 85-26, and high infection rates results in high production of PR-b1″ mRNA as shown by N. debneyi inoculated with virulent race 84-1 and N. glutinosa interacting with either avirulent (85-26) or virulent (84-1) races.
- Published
- 1993
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