Search

Your search keyword '"Ketner, Gary"' showing total 129 results
Start Over Author "Ketner, Gary"
129 results on '"Ketner, Gary"'

26. Capsid display of a conserved human papillomavirus L2 peptide in the adenovirus 5 hexon protein: a candidate prophylactic hpv vaccine approach.

Author

Wai-Hong Wu, Alkutkar, Tanwee, Karanam, Balasubramanyan, Roden, Richard B. S., Ketner, Gary, and Ibeanu, Okechukwu A.

Subjects
HUMAN papillomavirus vaccines, VIRAL vaccines, EPITOPES, CAPSIDS, VIRAL proteins, VIRUS-like particles, ADENOVIRUSES, AMINO acids
Abstract

Background: Infection by any one of 15 high risk human papillomavirus (hrHPV) types causes most invasive cervical cancers. Their oncogenic genome is encapsidated by L1 (major) and L2 (minor) coat proteins. Current HPV prophylactic vaccines are composed of L1 virus-like particles (VLP) that elicit type restricted immunity. An N-terminal region of L2 protein identified by neutralizing monoclonal antibodies comprises a protective epitope conserved among HPV types, but it is weakly immunogenic compared to L1 VLP. The major antigenic capsid protein of adenovirus type 5 (Ad5) is hexon which contains 9 hypervariable regions (HVRs) that form the immunodominant neutralizing epitopes. Insertion of weakly antigenic foreign B cell epitopes into these HVRs has shown promise in eliciting robust neutralizing antibody responses. Thus here we sought to generate a broadly protective prophylactic HPV vaccine candidate by inserting a conserved protective L2 epitope into the Ad5 hexon protein for VLP-like display. Methods: Four recombinant adenoviruses were generated without significant compromise of viral replication by introduction of HPV16 amino acids L2 12-41 into Ad5 hexon, either by insertion into, or substitution of, either hexon HVR1 or HVR5. Results: Vaccination of mice three times with each of these L2-recombinant adenoviruses induced similarly robust adenovirus-specific serum antibody but weak titers against L2. These L2-specific responses were enhanced by vaccination in the presence of alum and monophoryl lipid A adjuvant. Sera obtained after the third immunization exhibited low neutralizing antibody titers against HPV16 and HPV73. L2-recombinant adenovirus vaccination without adjuvant provided partial protection of mice against HPV16 challenge to either the vagina or skin. In contrast, vaccination with each L2-recombinant adenovirus formulated in adjuvant provided robust protection against vaginal challenge with HPV16, but not against HPV56. Conclusion: We conclude that introduction of HPV16 L2 12-41 epitope into Ad5 hexon HVR1 or HVR5 is a feasible method of generating a protective HPV vaccine, but further optimization is required to strengthen the L2-specific response and broaden protection to the more diverse hrHPV. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

32. Androgen Receptor Attenuation of Ad5 Replication: Implications for the Development of Conditionally Replication Competent Adenoviruses

Author

Höti, Naseruddin, primary, Li, Ying, additional, Chen, Chien-Lun, additional, Chowdhury, Wasim H, additional, Johns, David C, additional, Xia, Qinghua, additional, Kabul, Arup, additional, Hsieh, Jer-Tsong, additional, Berg, Michael, additional, Ketner, Gary, additional, Lupold, Shawn E, additional, and Rodriguez, Ronald, additional

Published
2007
Full Text
View/download PDF

36. Isolation, Growth, and Purification of Defective Adenovirus Deletion Mutants.

Author

Walker, John M., Wold, William S. M., Tollefson, Ann E., Ketner, Gary, and Boyer, Julie

Abstract

Defective adenovirus deletion mutants can be grown by complementation in the presence of helper viruses that supply essential functions missing in the deletion mutant. In general, the deletion mutant then must be separated physically from the helper for use in subsequent experiments. This chapter includes suggestions for selection of helper viruses, protocols for the production of stocks by complementation, and procedures for physical separation of deletion mutants from their helpers. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

37. Manipulation of Early Region 4.

Author

Walker, John M., Wold, William S. M., Tollefson, Ann E., Boyer, Julie, and Ketner, Gary

Abstract

Adenovirus early region 4 (E4) regulates processes in infected cells that include viral late gene expression, nonhomologous end joining, responses to DNA damage, and apoptosis. E4 is essential for viral growth in most cell lines. In this chapter, the current knowledge of the functions of six E4 products is summarized briefly. Protocols are presented for manipulation of E4, incorporation of E4 mutations into the viral genome, and growth of E4 mutants on complementing cell lines. A compilation of the described E4-complementing cell lines is included. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

42. A Replicating Adenovirus Capsid Display Recombinant Elicits Antibodies against Plasmodium falciparumSporozoites in Aotus nancymaaeMonkeys

Author

Karen, Kasey A., Deal, Cailin, Adams, Robert J., Nielsen, Carolyn, Ward, Cameron, Espinosa, Diego A., Xie, Jane, Zavala, Fidel, and Ketner, Gary

Abstract

ABSTRACTDecades of success with live adenovirus vaccines suggest that replication-competent recombinant adenoviruses (rAds) could serve as effective vectors for immunization against other pathogens. To explore the potential of a live rAd vaccine against malaria, we prepared a viable adenovirus 5 (Ad5) recombinant that displays a B-cell epitope from the circumsporozoite protein (CSP) of Plasmodium falciparumon the virion surface. The recombinant induced P. falciparumsporozoite-neutralizing antibodies in mice. Human adenoviruses do not replicate in mice. Therefore, to examine immunogenicity in a system in which, as in humans, the recombinant replicates, we constructed a similar recombinant in an adenovirus mutant that replicates in monkey cells and immunized four Aotus nancymaaemonkeys. The recombinant replicated in the monkeys after intratracheal instillation, the first demonstration of replication of human adenoviruses in New World monkeys. Immunization elicited antibodies both to the Plasmodiumepitope and the Ad5 vector. Antibodies from all four monkeys recognized CSP on intact parasites, and plasma from one monkey neutralized sporozoites in vitroand conferred partial protection against P. falciparumsporozoite infection after passive transfer to mice. Prior enteric inoculation of two animals with antigenically wild-type adenovirus primed a response to the subsequent intratracheal inoculation, suggesting a route to optimizing performance. A vaccine is not yet available against P. falciparum, which induces the deadliest form of malaria and kills approximately one million children each year. The live capsid display recombinant described here may constitute an early step in a critically needed novel approach to malaria immunization.

Published
2014
Full Text
View/download PDF

44. Isolation, Growth, and Purification of Defective Adenovirus Deletion Mutants.

Author

Walker, John M., Wold, William S. M., Ketner, Gary, and Boyer, Julie

Abstract

Adenovirus mutants that lack essential genes must be grown by complementation, the products of the missing genes supplied by a source other than the viral genome. Two methods are available for the growth of defective adenovirus mutants by complementation. For mutations confined to E1, E4, or portions of E2, complementing cell lines that contain segments of viral DNA and that can supply the missing viral products can be used to produce pure stocks of mutant particles (1-9). This approach will probably be extended to other regions of the viral genome, but may prove difficult to adapt to genes such as the late genes, whose products are required in large amounts by the virus. Alternatively, defective mutants can be grown as mixed stocks with a second helper virus that can supply in trans functions required by the mutant (10). Providing that a mutant contains all of the cis-active elements required for viral growth and is large enough to be packaged into an adenoviral capsid, there are in principle no restrictions on the DNA sequences that can be deleted from a mutant grown by complementation with helper virus. In addition, because the helper virus replicates, even products needed in large amounts can be effectively supplied in trans. Recently, adenoviral genomes constructed for gene therapy purposes and lacking nearly all viral sequences have been propagated in this way (11-13). [ABSTRACT FROM AUTHOR]

Published
1998
Full Text
View/download PDF

45. Manipulation of Early Region 4.

Author

Walker, John M., Wold, William S. M., Boyer, Julie, and Ketner, Gary

Abstract

Early region 4 (E4; Fig. 1A) occupies the right-hand 3000 bp of the human adenovirus genome. The sequences of E4 and E4 cDNAs indicate that E4 encodes seven polypeptides (1-4), most of which have been detected in infected cells. Analysis of E4 mutants has implicated E4 products in a variety of processes that occur in infected cells, including viral early and late gene expression, DNA replication, the shutoff of host-cell protein synthesis, transformation, and the ability to stimulate replication of adenovirus-associated virus (AAV). Specific E4 products have been implicated in many of those processes and, in some cases, information on the molecular mechanisms of E4 function is emerging. Current knowledge of the functions of E4 products is summarized below. [ABSTRACT FROM AUTHOR]

Published
1998
Full Text
View/download PDF

47. Adenovirus E4orf6 assembles with Cullin5-ElonginB-ElonginC E3 ubiquitin ligase through an HIV/SIV Vif-like BC-box to regulate p53.

Author

Kun Luo, Ehrlich, Elana, Zuoxiang Xiao, Wenyan Zhang, Ketner, Gary, and Xiao-Fang Yu

Subjects
VIRAL proteins, ADENOVIRUSES, GENETIC regulation, P53 antioncogene, UBIQUITIN, LIGASES, GENE silencing
Abstract

The adenovirus protein E4orf6 targets p53 for polyubiquitination and proteasomal degradation and is known to form a complex with the Cul5-ElonginB-ElonginC E3 ubiquitin ligase. However, whether Cul5 is directly responsible for the E4orf6-mediated degradation of p53 remains unclear. By using a dominant-negative mutant of CUl5 and silencing Cul5 expression through RNA interference, we have now demonstrated that E4orf6-mediated p53 degradation requires CUl5. Furthermore, we have identified a lenti-viral Vif-like BC-box motif in E4orf6 that is highly conserved among adenoviruses from multiple species. More importantly, we have shown that this Vif-like BC-box is essential for the recruitment of Cul5-ElonginB-ElonginC E3 ubiquitin ligase by E4orf6 and is also required for E4orf6-mediated p53 degradation. E4orf6 selectively recruited Cul5 despite the lack of either a Cul5-box, which is used by cellular substrate receptors to recruit Cul5, or a newly identified HCCH zinc-binding motif, which is used by primate lentiviral Vif to recruit Cul5. Therefore, adenovirus E4orf6 molecules represent a novel family of viral BC-box proteins the cellular ancestor of which is as yet unknown. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

50. A Deletion Mutation Placing the Galactokinase Gene of Escherichia coliunder Control of the Biotin Promoter

Author

Ketner, Gary and Campbell, Allan

Abstract

A deletion has been isolated which fuses galKand presumably galTto the promoter and operator of the bioAoperon. The deletion has endpoints in bioAand galE, and leaves the operator-proximal end of bioAintact and the regulatory sites themselves functional. In bacterial strains which carry the deletion, the expression of galKis regulated by biotin, although due to the inefficiency of the bioApromoter even the fully derepressed level of galactokinase is low. Electron micrographic examination of the mutation shows that it is a simple deletion, uncomplicated by other chromosomal abnormalities.

Published
1974
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results