Shabir Lakhi6, William Kilembe6, Guido Silvestri1, Paul. Goepfert5, Matthew .... Bazner2, Jake Tinsley3, Niall J. Lennon4, Matthew R. Henn4,. Eric Rosenberg2 ...
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Emory University, Atlanta, GA, United States, 2Microsoft Research, Redmond, WA, United States, 3Zambia Emory HIV Research Project, Lusaka, Zambia, 4University of AlabamaBirmingham, Birmingham, AL, United States, 5IAVI, San Francisco, CA, United States, 6IAVI, London, United Kingdom Background: HIV escapes adaptive cellular immunity by selecting mutations that are associated with the individual’s HLA-I alleles. These mutations can be transmitted but the impact of this process on pathogenesis is poorly understood. Methods: In 169 transmission pairs, we studied the transmission of HIV polymorphisms in Gag, Pol and Nef by Sanger sequencing of population amplicons in the donor (D) and the linked-recipient (LR) ( £ 3 months post-transmission). Polymorphisms statistically-linked to HLA alleles or located in well-defined CTL epitopes were quantified according to each LR’s HLA alleles and associated with their set-point VL and CD4 counts. Results: The majority of polymorphisms (83.6%) were transmitted from the D to the LR and a significant fraction (17.3%) was already adapted to the LR’s HLA (11.6% escape and 6.2% epitope-located). A Spearman correlation analysis showed that transmission of Pol polymorphisms irrelevant to the LR’s HLA was associated with a diminished set-point VL (p = 0.003). This association was lost (p = 0.4) when other variables known to determine set-point VL (gender-p = 0.01; B*57-p = 0.02; HLA-B sharing-p = 0.006; replicative capacity (RC)-p = 0.008) were included in a Generalized Linear Model. An in-depth analysis of survival curves (log-rank test) for different CD4 endpoints (200– 350 cells/ul) showed that the proportion of transmitted HLAlinked polymorphisms relevant to the LR’ HLA in Gag was consistently associated with a faster CD4 decline (p = 0.0004). When other factors (gender, protective alleles, allele sharing, RC and set-point VL) were considered in a Cox Proportional Hazard Model, the proportion of transmitted HLA-linked polymorphisms in Gag remained the only variable significantly associated with CD4 decline (p = 0.03). Conclusions: Because most Gag, Pol and Nef polymorphisms are transmitted, newly infected individuals can receive a preadapted variant that leads to an accelerated disease progression (faster CD4 decline) without showing a significant effect on setpoint VL.
OA21.02 The Sequence of the a4b7-binding Motif on Gp120 of Transmitted/Founder Viruses Contributes to the Dependence on the Integrin for HIV Infection
(GALT), a site of rapid HIV replication, has been described as an attachment factor for the V2 loop of the envelope protein gp120. We aimed to study the factors that influence dependence on a4b7 for replication of transmitted/founder viruses including cytokine levels in cervicovaginal lavage (CVL), STI infections and the sequence of the tripeptide a4b7-binding motif. Methods: All-trans retinoic acid-activated CD4 + T cells were incubated with or without HP2/1 (anti-a4 antibody) or Act-1 (anti-a4b7 antibody) prior to adding virus. Infectious virus was prepared using envelope genes of the transmitted/founder (T/F) virus from 8 individuals in the CAPRISA Acute Infection cohort. Replication was monitored by p24 ELISA. Changes in viral sequence were generated by site-directed mutagenesis. Results: T/F viruses with the highest dependence on a4b7 for replication had P/SDI/V motifs while those with lower dependence were LDI/L. Mutation of viruses with LDI/L motifs to P/SDI/V resulted in increased dependence on a4b7 for replication while the reverse mutation restricted the ability of the viruses to enter cells. T/F viruses from individuals diagnosed with bacterial vaginosis (BV) at the time of virus isolation had significantly higher dependence on the integrin for replication. Levels of IL-7, a cytokine that upregulates a4b7 expression, correlated with a4b7 dependence in the CVL shortly after transmission. Both BV status and high IL-7 levels in the CVL were associated with the P/SDI/V motifs in a larger cohort of 28 CAPRISA 002 participants. Conclusions: P/SDI/V motifs are more common among South African HIV subtype C viruses accounting for 35% of variants. These data suggest that viruses with P/SDI/V motifs favour a4b7 reactivity at transmission influenced by the presence of BV and IL-7 cytokine levels. These findings may lead to vaccine and therapeutic opportunities in which a4b7 reactivity is exploited.
OA21.03 HIV Replicative Capacity of Transmitted Viruses Is Associated with Early Immune Activation, Exhaustion and Establishment of the Viral Reservoir Jessica L. Prince1, Daniel T. Claiborne1, Gladys Macharia2, Luca Micci1, Benton Lawson1, Eileen Scully3, Jakub Kopycinski4, Thomas Vanderford1, Jianming Tang5, Tianwei Yu1, Shabir Lakhi6, William Kilembe6, Guido Silvestri1, Paul Goepfert5, Matthew A. Price2,7, Marcus Altfeld8, Mirko Paiardini1, Jill Gilmour2, Susan Allen1,6, Eric Hunter1 1
Simone I. Richardson1,2, Elin Gray1, Nonhlanhla Mkhize1,2, Daniel Sheward3, Bronwen Lambson1,2, Kurt Wibmer1,2, Lindi Masson3, Lise Werner4, Nigel Garett4, Jo-Ann Passmore3, Salim Abdool-Karim4, Carolyn Williamson3, Penny Moore1,2, Lynn Morris1,2 1
Centre for HIV and STI’s, National Institute for Communicable Diseases, Johannesburg, South Africa, 2School of Pathology, University of the Witwatersrand, Johannesburg, South Africa, 3Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa, 4 Centre for the AIDS Programme of Research in South Africa (CAPRISA), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa Background: The integrin a4b7, which mediates the trafficking of T lymphocytes to the gut associated lymphoid tissue
Emory University, Atlanta, GA, United States, 2International AIDS Vaccine Initiative (IAVI), London, United Kingdom, 3 Ragon Institute of MGH, MIT and Harvard, Boston, MA, United States, 4Imperial College London, London, United Kingdom, 5University of Alabama at Birmingham, Birmingham, AL, United States, 6Zambia Emory HIV Research Project, Lusaka, Zambia, 7UCSF, San Francisco, CA, United States, 8 Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany Background: Determining the host and viral factors that shape the trajectory of early HIV-1 pathogenesis is key for developing rational prevention strategies. Previously, we showed that in individuals recently infected with HIV-1 subtype C, low viral replicative capacity (RC) as defined by the transmitted Gag sequence, was associated with a delayed loss of CD4 T cells independent of set point VL and host immunogenetic factors. We hypothesize that low RC leads to a muted inflammatory response characterized by
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reduced immune activation, might attenuate infection of memory T cell subsets and preserve critical CD4 T cell homeostasis. Methods: Levels of plasma cytokines at seroconversion were measured using a Luminex platform. Flow cytometry was used to assess markers of activation (CD38 + HLADR + ), exhaustion (PD-1 and CD57), and proliferation (Ki-67) on CD4 and CD8 cells. Cell associated viral DNA in CD4 memory populations was quantified with qPCR. Results: RC was positively correlated with levels of inflammatory cytokines in plasma and with activation of both CD8 (p = 0.01) and central memory (CM) CD4 T cells (p = 0.002). Low RC was associated with CD8 T cells that were less exhausted (p < 0.001) and more cytotoxic (p = 0.002). RC was positively correlated with proliferation (p = 0.003) and with the level of cell associated viral DNA in CM CD4 T cells (p = 0.01), a population highlighted to be integral for the maintenance of latency and preferentially spared in non-pathogenic SIV infection. Consistent with previous studies, we observed that cellular immune activation, proliferation, exhaustion, and cell associated viral DNA in CM CD4 T cells were all associated with the rate of disease progression. Conclusions: This study highlights the integral role that RC of the transmitted virus plays in defining several facets of HIV-1 immunopathology. Understanding the complex interactions between HIV and the immune system will be crucial for designing innovative prevention strategies. JP and DC contributed equally to this work
OA21.04 In Vitro Fitness of HIV-1 Transmitted/Founder versus Non-transmitted Full-length Genome Infectious Molecular Clones Martin J. Deymier1, Zachary Ende1, Daniel T. Claiborne1, William Kilembe2, Susan Allen1,2, Eric Hunter1,2 1
Emory University, Atlanta, GA, United States, 2Zambia Emory HIV Research Program, Lusaka, Zambia
Background: In *80% of heterosexual transmissions of HIV-1, an infected individual with a diverse viral quasispecies transmits a single viral variant, the Transmitted/Founder (TF), to a naı¨ve host. Evidence is building that TF variants are enriched for certain genetic and phenotypic characteristics that presumably enhance the efficiency of transmission. However, the mechanisms involved are largely ambiguous, partially because studies using full-length genomes in transmission pairs are lacking. Methods: We have performed HIV near full-length (NFL) single genome amplification from six subtype C acutely infected individuals and each of their chronically infected virologically linked partners in the Zambia-Emory HIV Research Project. Phylogenetic analysis performed on the 118 NFL genomes (mean 18/transmission pair) confirms epidemiologically linked transmission as well as infection by a single viral variant in each case. We have generated 5 TF & 34 non-transmitted (NT) full-length infectious molecular clones from 5 transmission pairs and assayed for particle infectivity by dividing the virus titer on TZM-bl cells by the RT activity of the virus stock. Results: The particle infectivity of the TF compared to the median of the NT variants for all matched transmission pairs was not statistically significant (p = 0.22). However, particle infectivity correlated with the amount of glycosylation on the Env
V1-V4 region (R = 0.40, p = 0.01) as well as with replication in PBMCs for a subset of tested viruses (R = .823 p = 0.01), suggesting that previous findings showing less glycosylation on TF viruses could mean lower replicative capacities in vitro. However, preliminary data suggests that lower replicating, less glycosylated viruses, may preferentially productively infect monocyte-derived dendritic cells. Conclusions: Understanding the characteristics of TF viruses that allow for efficient transmission will aid in prophylaxis and early intervention efforts.
OA21.05 Genetic Footprints within the HIV-1 Envelope Glycoprotein Associated with Transmission in Men Who Have Sex with Men Damien C. Tully1, Colin B. Ogilvie1, Rebecca Batorsky1, Karen A. Power1, Hunter Bedard1, Aaron Seese1, Molly Amero1, Sue Bazner2, Jake Tinsley3, Niall J. Lennon4, Matthew R. Henn4, Eric Rosenberg2, Kenneth H. Mayer3, Heiko Jessen5, Marcus Altfeld1,6, Todd M. Allen1 1 Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, United States, 2Massachusetts General Hospital, Infectious Disease, Boston, MA, United States, 3The Fenway Institute, Fenway Health, Boston, MA, United States, 4The Broad Institute of MIT and Harvard, Cambridge, MA, United States, 5 HIV Clinic Praxis, Jessen, Berlin, Germany, 6Heinrich-PetteInstitut, Viral Immunology, Hamburg, Germany
Background: The global spread of HIV - 1 has been fueled by sexual transmission with the epidemic disproportionately affecting men who sex with men (MSM). As the epidemic in MSM continues unabated, understanding the virus-host interactions responsible for transmission may be critical for the development of an HIV vaccine and other prevention strategies. Methods: To elucidate the nature of the transmitted/founder (TF) virus following rectal transmission, we developed a novel analytical strategy utilizing deep sequencing data from a cohort of 67 acutely infected MSM subjects. Results: Empirical analyses revealed that deep sequencing could not only reliably infer the TF virus but also discriminate between single and multiple HIV infections. Using this approach we found that most transmissions resulted from a single infection with only 16% of individuals exhibiting evidence of multiple variant transmissions. We extended this study to identify signature mutations that may be favored at transmission between viruses originating from heterosexual exposure versus those from MSM. Here, we focused on a comprehensive analysis of Env sequences from 125 early subjects (Fiebig I-III) to discern the genetic imprint on the underlying composition of the viral quasispecies. A number of genetic signatures were identified in gp120 and the gp41 cytoplasmic tail. One signature pattern specifically enriched in TF viruses from MSM was the loss of an N-linked glycosylation site at position 362 in the C3 region adjacent to the CD4 binding site. The loss of this glycosylation motif has previously been associated with chronic infection and implicated in increased cell-to-cell fusion activity and a high apoptosis inducing phenotype. Conclusions: Taken together, these findings provide unique insight into the events of early transmission in MSM and reveal potentially important mechanistic differences that may exist between the different routes of sexual transmission that are not yet fully understood.
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