Search

Objectives: The Maraviroc Switch (MARCH) study week 48 data demonstrated that maraviroc, a chemokine receptor-5 (CCR5) inhibitor, was a safe and effective switch for the ritonavir-boosted protease inhibitor (PI/r) component of a two nucleos(t)ide reverse transcriptase inhibitor [N(t)RTI] plus PI/r-based antiretroviral regimen in patients with R5-tropic virus. Here we report the durability of this finding. Methods: MARCH, an international, multicentre, randomized, 96-week open-label switch study, enrolled HIV-1-infected adults with R5-tropic virus who were stable (> 24 weeks) and virologically suppressed [plasma viral load (pVL) < 50 HIV-1 RNA copies/mL]. Participants were randomized to continue their current PI/r-based regimen (PI/r) or to switch to MVC plus two N(t)RTIs (MVC) (1:2 randomization). The primary endpoint was the difference in the proportion with pVL < 200 copies/mL at 96 weeks. The switch arm was defined as noninferior if the lower limit of the 95% confidence interval (CI) for the difference was < −12% in the intention-to-treat (ITT) population. Safety endpoints (the difference in the mean change from baseline or a comparison of proportions) were analysed as key secondary endpoints. Results: Eighty-two (PI/r) and 156 (MVC) participants were randomized and included in the ITT analysis; 71 (87%) and 130 (83%) were in follow-up and on therapy at week 96. At week 96, 89.0% and 90.4% in the PI/r and MVC arms, respectively, had pVL < 50 copies/mL (95% CI -6.6, 10.2). Moreover, in those switching away from PI/r, there were significant reductions in mean total cholesterol (differences 0.31 mmol/L; P = 0.02) and triglycerides (difference 0.44 mmol/L; P < 0.001). Changes in CD4 T-cell count, renal function, and serious and nonserious adverse events were similar in the two arms. Conclusions: MVC as a switch for a PI/r is safe and effective at maintaining virological suppression while having significant lipid benefits over 96 weeks.

Objectives: The Maraviroc Switch (MARCH) study week 48 data demonstrated that maraviroc, a chemokine receptor-5 (CCR5) inhibitor, was a safe and effective switch for the ritonavir-boosted protease inhibitor (PI/r) component of a two nucleos(t)ide reverse transcriptase inhibitor [N(t)RTI] plus PI/r-based antiretroviral regimen in patients with R5-tropic virus. Here we report the durability of this finding. Method(s): MARCH, an international, multicentre, randomized, 96-week open-label switch study, enrolled HIV-1-infected adults with R5-tropic virus who were stable (> 24 weeks) and virologically suppressed [plasma viral load (pVL) < 50 HIV-1 RNA copies/mL]. Participants were randomized to continue their current PI/r-based regimen (PI/r) or to switch to MVC plus two N(t)RTIs (MVC) (1:2 randomization). The primary endpoint was the difference in the proportion with pVL < 200 copies/mL at 96 weeks. The switch arm was defined as noninferior if the lower limit of the 95% confidence interval (CI) for the difference was < -12% in the intention-to-treat (ITT) population. Safety endpoints (the difference in the mean change from baseline or a comparison of proportions) were analysed as key secondary endpoints. Result(s): Eighty-two (PI/r) and 156 (MVC) participants were randomized and included in the ITT analysis; 71 (87%) and 130 (83%) were in follow-up and on therapy at week 96. At week 96, 89.0% and 90.4% in the PI/r and MVC arms, respectively, had pVL < 50 copies/mL (95% CI -6.6, 10.2). Moreover, in those switching away from PI/r, there were significant reductions in mean total cholesterol (differences 0.31 mmol/L; P = 0.02) and triglycerides (difference 0.44 mmol/L; P < 0.001). Changes in CD4 T-cell count, renal function, and serious and nonserious adverse events were similar in the two arms. Conclusion(s): MVC as a switch for a PI/r is safe and effective at maintaining virological suppression while having significant lipid benefits over 96 weeks.Copyright © 2017 British H

Human leukocyte antigen class I (HLA)-restricted CD8(+) T lymphocyte (CTL) responses are crucial to HIV-1 control. Although HIV can evade these responses, the longer-term impact of viral escape mutants remains unclear, as these variants can also reduce intrinsic viral fitness. To address this, we here developed a metric to determine the degree of HIV adaptation to an HLA profile. We demonstrate that transmission of viruses that are pre-adapted to the HLA molecules expressed in the recipient is associated with impaired immunogenicity, elevated viral load and accelerated CD4(+) T cell decline. Furthermore, the extent of pre-adaptation among circulating viruses explains much of the variation in outcomes attributed to the expression of certain HLA alleles. Thus, viral pre-adaptation exploits 'holes' in the immune response. Accounting for these holes may be key for vaccine strategies seeking to elicit functional responses from viral variants, and to HIV cure strategies that require broad CTL responses to achieve successful eradication of HIV reservoirs.

HLA-B*57:01 and HLA-B*57:03, the most prevalent HLA-B*57 subtypes in Caucasian and African populations, respectively, are the HLA alleles most protective against HIV disease progression. Understanding the mechanisms underlying this immune control is of critical importance and yet remains unclear. Unexplained differences are observed in the impact of the dominant CTL response restricted by HLA-B*57:01 and HLA-B*57:03 in chronic infection towards the Gag epitope KAFSPEVIPMF (‘KF11’ ,Gag162-172). We previously showed that the HLA-B*57:03-KF11 response is associated with a >1 log lower viral setpoint in C-clade infection and that this response selects escape mutants within the epitope. We first examined the relationship of KF11 responses in B-clade infected subjects with HLA-B*57:01 to immune control and observed that a detectable KF11 response was associated with a >1 log higher viral load (p=0.02). No evidence of HLA-B*57:01-KF11 associated selection pressure was identified in previous comprehensive analyses of >1800 B-clade infected subjects infected. We then studied a B-clade infected cohort in Barbados where HLA-B*57:03 is highly prevalent. In contrast to B-clade infected subjects expressing HLA-B*57:01, we observed strong selection pressure driven by the HLA-B*57:03-KF11 response for the escape mutation S173T. This mutation reduces recognition of virus-infected cells by HLA-B*57:03-KF11 CTL, and is associated with a >1 log increase in viral load in HLA-B*57:03-positive subjects (p=0.009). We demonstrate functional constraints imposed by HIV clade relating to the residue at Gag-173 that explain the differential clade-specific escape patterns in HLA-B*57:03 subjects. Further studies are needed to evaluate the role of the KF11 response in HLA-B*57:01-associated HIV disease protection.

The interaction between follicular T helper cells (TFH) and B cells in the lymph nodes and spleen has a major impact on the development of antigen-specific B cell responses during infection or vaccination. Recent studies described a functional equivalent of these cells among circulating CD4 T cells, referred to as peripheral TFH cells. Here, we characterize the phenotype and in vitro B cell helper activity of peripheral TFH populations, as well as the effect of HIV infection on these populations. In co-culture experiments we confirmed CXCR5+ cells from HIV-uninfected donors provide help to B cells and more specifically, we identified a CCR7(high)CXCR5(high)CCR6(high)PD-1(high) CD4 T cell population that secretes IL-21 and enhances isotype-switched immunoglobulin production. This population is significantly decreased in treatment-naïve, HIV-infected individuals and can be recovered after anti-retroviral therapy. We found impaired immunoglobulin production in co-cultures from HIV-infected individuals and found no correlation between the frequency of peripheral TFH cells and memory B cells, or with neutralization activity in untreated HIV infection in our cohort. Furthermore, we found that within the peripheral TFH population, the expression level of TFH-associated genes more closely resembles a memory, non-TFH population, as opposed to a TFH population. Overall, our data identify a heterogeneous population of circulating CD4 T cells that provides in vitro help to B cells, and challenges the origin of these cells as memory TFH cells.

HLA class I-associated polymorphisms identified at the population level mark viral sites under immune pressure by individual HLA alleles. As such, analysis of their distribution, frequency, location, statistical strength, sequence conservation, and other properties offers a unique perspective from which to identify correlates of protective cellular immunity. We analyzed HLA-associated HIV-1 subtype B polymorphisms in 1,888 treatment-naïve, chronically infected individuals using phylogenetically informed methods and identified characteristics of HLA-associated immune pressures that differentiate protective and nonprotective alleles. Over 2,100 HLA-associated HIV-1 polymorphisms were identified, approximately one-third of which occurred inside or within 3 residues of an optimally defined cytotoxic T-lymphocyte (CTL) epitope. Differential CTL escape patterns between closely related HLA alleles were common and increased with greater evolutionary distance between allele group members. Among 9-mer epitopes, mutations at HLA-specific anchor residues representedthe most frequently detected escape type: these occurred nearly 2-fold more frequently than expected by chance and were computationally predicted to reduce peptide-HLA binding nearly 10-fold on average. Characteristics associated with protective HLA alleles (defined using hazard ratios for progression to AIDS from natural history cohorts) included the potential to mount broad immune selection pressures across all HIV-1 proteins except Nef, the tendency to drive multisite and/or anchor residue escape mutations within known CTL epitopes, and the ability to strongly select mutations in conserved regions within HIV's structural and functional proteins. Thus, the factors defining protective cellular immune responsesmay be more complex than simply targeting conserved viral regions. The results provide new information to guide vaccine design and immunogenicity studies.

Approximately 1 million people in the United States and over 30 million worldwide are living with human immunodeficiency virus type 1 (HIV-1). While mortality from untreated infection approaches 100%, survival improves markedly with use of contemporary antiretroviral therapies (ART). In the United States, 25 drugs are approved for treating HIV-1, and increasing numbers are available in resource-limited countries. Safe and effective ART is a cornerstone in the global least in part to human genetic variants that affect drug metabolism, drug disposition, and off-site drug targets. Defining effects of human genetic variants on HIV treatment toxicity, efficacy, and pharmacokinetics has far-reaching implications. In 2010, the National Institute of Allergy and Infectious Diseases sponsored a workshop entitled, Pharmacogenomics – A Path Towards Personalized HIV Care. This article summarizes workshop objectives, presentations, discussions, and recommendations derived from this meeting.

Strong statistical associations between polymorphisms in HIV-1 population sequences and carriage of HLA class I alleles have been widely used to identify possible sites of CD8 T cell immune selection in vivo. However, there have been few attempts to prospectively and systematically test these genetic hypotheses arising from population-based studies at a cellular, functional level. We assayed CD8 T cell epitope-specific IFN-gamma responses in 290 individuals from the same cohort, which gave rise to 874 HLA-HIV associations in genetic analyses, taking into account autologous viral sequences and individual HLA genotypes. We found immunological evidence for 58% of 374 associations tested as sites of primary immune selection and identified up to 50 novel HIV-1 epitopes using this reverse-genomics approach. Many HLA-adapted epitopes elicited equivalent or higher-magnitude IFN-gamma responses than did the nonadapted epitopes, particularly in Nef. At a population level, inclusion of all of the immunoreactive variant CD8 T cell epitopes in Gag, Pol, Nef, and Env suggested that HIV adaptation leads to an inflation of Nef-directed immune responses relative to other proteins. We concluded that HLA-HIV associations mark viral epitopes subject to CD8 T cell selection. These results can be used to guide functional studies of specific epitopes and escape mutations, as well as to test, train, and evaluate analytical models of viral escape and fitness. The inflation of Nef and HLA-adapted variant responses may have negative effects on natural and vaccine immunity against HIV and, therefore, has implications for diversity coverage approaches in HIV vaccine design.

Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA-viral peptide interaction as the major factor modulating durable control of HIV infection.

Currently, 1.1 million individuals in the United States are living with HIV-1 infection. Although this is a relatively small proportion of the global pandemic, the remarkable mix of ancestries in the United States, drawn together over the past two centuries of continuous population migrations, provides an important and unique perspective on adaptive interactions between HIV-1 and human genetic diversity. HIV-1 is a rapidly adaptable organism and mutates within or near immune epitopes that are determined by the HLA class I genotype of the infected host. We characterized HLA-associated polymorphisms across the full HIV-1 proteome in a large, ethnically diverse national United States cohort of HIV-1-infected individuals. We found a striking divergence in the immunoselection patterns associated with HLA variants that have very similar or identical peptide-binding specificities but are differentially distributed among racial/ethnic groups. Although their similarity in peptide binding functionally clusters these HLA variants into supertypes, their differences at sites within the peptide-binding groove contribute to race-specific selection effects on circulating HIV-1 viruses. This suggests that the interactions between the HLA/HIV peptide complex and the TCR vary significantly within HLA supertype groups, which, in turn, influences HIV-1 evolution.

Background: Despite the extensive genetic diversity of HIV-1, viral evolution in response to immune selective pressures follows broadly predictable mutational patterns. Sites and pathways of Human Leukocyte-Antigen (HLA)-associated polymorphisms in HIV-1 have been identified through the analysis of population-level data, but the full extent of immune escape pathways remains incompletely characterized. Here, in the largest analysis of HIV-1 subtype B sequences undertaken to date, we identify HLA-associated polymorphisms in the three HIV-1 proteins most commonly considered in cellular-based vaccine strategies. Results are organized into protein-wide escape maps illustrating the sites and pathways of HLA-driven viral evolution. Methodology/Principal Findings: HLA-associated polymorphisms were identified in HIV-1 Gag, Pol and Nef in a multicenter cohort of >1500 chronically subtype-B infected, treatment-naïve individuals from established cohorts in Canada, the USA and Western Australia. At q≤0.05, 282 codons commonly mutating under HLA-associated immune pressures were identified in these three proteins. The greatest density of associations was observed in Nef (where close to 40% of codons exhibited a significant HLA association), followed by Gag then Pol (where ∼15-20% of codons exhibited HLA associations), confirming the extensive impact of immune selection on HIV evolution and diversity. Analysis of HIV codon covariation patterns identified over 2000 codon-codon interactions at q≤0.05, illustrating the dense and complex networks of linked escape and secondary/compensatory mutations. Conclusions/Significance: The immune escape maps and associated data are intended to serve as a user-friendly guide to the locations of common escape mutations and covarying codons in HIV-1 subtype B, and as a resource facilitating the systematic identification and classification of immune escape mutations. These resources should facilitate research in HIV epitope discovery and host-pathog

Background: Despite the extensive genetic diversity of HIV-1, viral evolution in response to immune selective pressures follows broadly predictable mutational patterns. Sites and pathways of Human Leukocyte-Antigen (HLA)-associated polymorphisms in HIV-1 have been identified through the analysis of population-level data, but the full extent of immune escape pathways remains incompletely characterized. Here, in the largest analysis of HIV-1 subtype B sequences undertaken to date, we identify HLA-associated polymorphisms in the three HIV-1 proteins most commonly considered in cellular-based vaccine strategies. Results are organized into protein-wide escape maps illustrating the sites and pathways of HLA-driven viral evolution. Methodology/Principal Findings: HLA-associated polymorphisms were identified in HIV-1 Gag, Pol and Nef in a multicenter cohort of >1500 chronically subtype-B infected, treatment-naïve individuals from established cohorts in Canada, the USA and Western Australia. At q≤0.05, 282 codons commonly mutating under HLA-associated immune pressures were identified in these three proteins. The greatest density of associations was observed in Nef (where close to 40% of codons exhibited a significant HLA association), followed by Gag then Pol (where ∼15-20% of codons exhibited HLA associations), confirming the extensive impact of immune selection on HIV evolution and diversity. Analysis of HIV codon covariation patterns identified over 2000 codon-codon interactions at q≤0.05, illustrating the dense and complex networks of linked escape and secondary/compensatory mutations. Conclusions/Significance: The immune escape maps and associated data are intended to serve as a user-friendly guide to the locations of common escape mutations and covarying codons in HIV-1 subtype B, and as a resource facilitating the systematic identification and classification of immune escape mutations. These resources should facilitate research in HIV epitope discovery and host-pathog

Background: The relationship between immune escape and HIV disease is incompletely understood. Here we examine the relationship between CTL selection pressure and plasma viral load (pVL) by defining HLA class I-associated polymorphisms in Gag, Pol and Nef in a large cohort of untreated HIV-1 subtype B-infected persons. Methods: HLA-associated polymorphisms were identified in >1200 chronically-infected, treatment-naïve individuals from Canada (HOMER cohort), the USA (ACTG5142/5128 protocols), and Western Australia (WAHC), using phylogenetically-corrected analysis methods incorporating a multivariate adjustment for HLA linkage disequilibrium and a q-value correction for multiple tests. In individuals for whom clinical data were available (N~550), correlations between pVL and HLA-associated polymorphisms were assessed using Spearman’s rank test. Results: >1000 unique HLA-associated polymorphisms were identified, but the number of codons involved varied by protein: 22%, 16% and 48% of Gag, Pol and Nef codons harbored an HLA-associated polymorphism. Roughly 60% of polymorphisms mapped in or near known or predicted CTL epitopes; a further 20% likely represent compensatory mutations. A modest inverse correlation was observed between the total number of HLA-associated sites in Gag (but not Pol/Nef) and pVL (R=-0.13;p=0.002), suggesting that Gag CTL targeting contributes more substantially to viremia control than targeting other proteins. A positive correlation was observed between the proportion of escaped Gag (but not Pol/Nef) sites and pVL (R=0.11;p=0.01), suggesting that the consequences of escape in Gag may be greater than other proteins. Conclusion: Results support strong CTL-mediated selection on HIV, the effects of which vary by protein. The list of >1000 HLA-associated polymorphisms represents the most comprehensive to date for HIV-subtype-B. The associations between pVL and CTL selection pressure/escape in Gag suggest that in vivo CTL targeting of Gag may be import

No abstract available

adult, http://name.umdl.umich.edu/IC-INSECT2IC-X-UMMZI-97468%5DUMMZ-INS-97468, https://quod.lib.umich.edu/cgi/i/image/api/thumb/insect2ic/UMMZI-97468/UMMZ-INS-97468/!250,250, The University of Michigan Library provides access to these materials for educational and research purposes. These materials may be under copyright. If you decide to use any of these materials, you are responsible for making your own legal assessment and securing any necessary permission. If you have questions about the collection, contact the Collections Manager: insect-dlps-help@umich.edu. If you have concerns about the inclusion of an item in this collection, please contact Library Information Technology: libraryit-info@umich.edu., https://www.lib.umich.edu/about-us/policies/copyright-policy

adult, http://name.umdl.umich.edu/IC-INSECT2IC-X-UMMZI-130400%5DUMMZ-INS-130400, https://quod.lib.umich.edu/cgi/i/image/api/thumb/insect2ic/UMMZI-130400/UMMZ-INS-130400/!250,250, The University of Michigan Library provides access to these materials for educational and research purposes. These materials may be under copyright. If you decide to use any of these materials, you are responsible for making your own legal assessment and securing any necessary permission. If you have questions about the collection, contact the Collections Manager: insect-dlps-help@umich.edu. If you have concerns about the inclusion of an item in this collection, please contact Library Information Technology: libraryit-info@umich.edu., https://www.lib.umich.edu/about-us/policies/copyright-policy

adult, http://name.umdl.umich.edu/IC-INSECT2IC-X-UMMZI-127176%5DUMMZ-INS-127176, https://quod.lib.umich.edu/cgi/i/image/api/thumb/insect2ic/UMMZI-127176/UMMZ-INS-127176/!250,250, The University of Michigan Library provides access to these materials for educational and research purposes. These materials may be under copyright. If you decide to use any of these materials, you are responsible for making your own legal assessment and securing any necessary permission. If you have questions about the collection, contact the Collections Manager: insect-dlps-help@umich.edu. If you have concerns about the inclusion of an item in this collection, please contact Library Information Technology: libraryit-info@umich.edu., https://www.lib.umich.edu/about-us/policies/copyright-policy

adult, http://name.umdl.umich.edu/IC-INSECT2IC-X-UMMZI-127175%5DUMMZ-INS-127175, https://quod.lib.umich.edu/cgi/i/image/api/thumb/insect2ic/UMMZI-127175/UMMZ-INS-127175/!250,250, The University of Michigan Library provides access to these materials for educational and research purposes. These materials may be under copyright. If you decide to use any of these materials, you are responsible for making your own legal assessment and securing any necessary permission. If you have questions about the collection, contact the Collections Manager: insect-dlps-help@umich.edu. If you have concerns about the inclusion of an item in this collection, please contact Library Information Technology: libraryit-info@umich.edu., https://www.lib.umich.edu/about-us/policies/copyright-policy

adult, http://name.umdl.umich.edu/IC-INSECT2IC-X-UMMZI-123490%5DUMMZ-INS-123490, https://quod.lib.umich.edu/cgi/i/image/api/thumb/insect2ic/UMMZI-123490/UMMZ-INS-123490/!250,250, The University of Michigan Library provides access to these materials for educational and research purposes. These materials may be under copyright. If you decide to use any of these materials, you are responsible for making your own legal assessment and securing any necessary permission. If you have questions about the collection, contact the Collections Manager: insect-dlps-help@umich.edu. If you have concerns about the inclusion of an item in this collection, please contact Library Information Technology: libraryit-info@umich.edu., https://www.lib.umich.edu/about-us/policies/copyright-policy