CROI 2019 Abstract eBook

Abstract eBook

Poster Abstracts

S. Morrison 3 , Stephen Elledge 2 , Ron Brookmeyer 4 , Ingo Ruczinski 1 , H. Benjamin Larman 1 , Susan H. Eshleman 1 1 Johns Hopkins University, Baltimore, MD, USA, 2 Harvard University, Boston, MA, USA, 3 FHI 360, Durham, NC, USA, 4 University of California Los Angeles, Los Angeles, CA, USA Background: The HIV immune response evolves during infection and may be impacted by factors such as antiretroviral treatment (ART). We used a massively-multiplexed system to profile the antibody (Ab) response to HIV infection in individuals with early to late stage infection and to evaluate the relationship between Ab diversity and ART initiation. Methods: Ab profiles were analyzed with the VirScan assay. This assay uses phage immunoprecipitation sequencing to quantify Ab binding to >3,300 HIV peptides spanning the HIV genome. The analysis included 403 samples from 57 African women with known duration of HIV infection (14 days to 8.7 years). ART was started at a CD4 count <250 cells/mm 3 ; 32/57 women started ART during the study period (ART group). For each sample, network graphs were used to calculate the number of unique non-overlapping epitopes that had high levels of Ab binding (Ab breadth). We measured the change in Ab breadth 9-24 months after infection and compared time to ART initiation among those with declining vs. stable or increasing Ab breadth. We also analyzed the associations between the rate of change in Ab breadth over time, ART initiation, and other factors. Results: In most persons, Ab breadth increased during the first 6 months of infection. In the non-ART group, Ab breath reached a plateau (“Ab breadth set point”) 9-12 months after infection. In the ART group, analysis using a Cox proportional hazards model showed that those who had stable or increasing Ab breadth 9-24 months after infection started ART later than those with decreasing Ab breadth (log-rank test for earlier ART initiation: p=0.009, hazards ratio: 0.29, 95% CI: 0.11, 0.78, p=0.014). A faster decline in Ab breadth was correlated with lower baseline CD4 cell count (p=0.002) and higher pre-ART viral load set point (p=0.001). Ab breadth stabilized after ART initiation at levels similar to those seen in early HIV infection. Conclusion: Deep profiling of the antibody response to HIV infection identified a novel feature of the anti-HIV immune response, Ab breadth, that was associated with clinically-significant outcomes. 221 HIV INFECTION ALTERS DYNAMIC MACROPHAGE: T-CELL INTERACTIONS TO PROMOTE VIRAL SPREAD Paul Gabriel C. Lopez , Wan Koh, Ryan Hnatiuk, Thomas Murooka University of Manitoba, Winnipeg, MB, Canada Background: Recent studies suggest that tissue macrophages and microglia represent an important, long-lived HIV reservoir in vivo. While T cells are the main target of HIV infection, antigen-presenting cells like macrophages contribute to the activation/maintenance of these cells. HIV is known to be transmitted via cell-cell contact, but the cellular and molecular dynamics of HIV spread using 3D systems recapitulating the lymphoid structures remains unclear. Methods: We developed a model to dynamically characterize macrophage:T cell contacts within 3D collagen matrices. HIV-infected monocyte-derived macrophages (MDM) were co-cultured with autologous CD4+ T cells and changes in migration behaviors and cell-cell contact dynamics were visually characterized using live-cell microscopy. In parallel, viral spread kinetics was measured in collagen gels. The role of virus- and host-derived adhesive molecules in facilitating stable MDM:T cell contacts were assessed using blocking antibodies. The efficacy of various antiretroviral drugs was also explored during dynamic cell-cell transmission. Results: We observed substantial changes in MDMmorphology following HIV infection: the formation of long, irregular podosomal extensions were a direct result of Nef expression. While Nef-induced podosomes did not enhance T cell contacts, HIV infection of MDM led to a dramatic increase in stable conjugates. We show that such stable contacts are a pre-requisite for enhanced HIV dissemination. Antiretroviral drugs at concentrations that completely suppresses infection by cell-free HIV, only reduced infection to 43±19% (raltegravir), while tenofovir and emtricitabine reduced infection to 36±5% and 71±6%, respectively. We further show that gp120:CD4 interactions are key regulators of MDM:T cell contacts, which is further supported by LFA- 1:ICAM-1 adhesive contacts. Blockade of LFA-1 led to destabilization of MDM:T cell contacts and translated into a substantial reduction (~70%) in infection. Interestingly, blocking LFA-1:ICAM-1 contacts caused long tethering events, which we interpret as a result of incomplete restraint of motile T cells.

219 IN VIVO MODEL FOR HBV/HIV COINFECTION STUDIES

Weimin Wang, Raghubendra S. Dagur, Edward Makarov, Yimin Sun, Catherine L. Gebhart, Murali L. Ganesan, Natalia Osna, Larisa Y. Poluektova University of Nebraska Medical Center, Omaha, NE, USA Background: The interplay between innate immune responses of hepatocytes to HBV in the setting of ongoing HIV-1 replication require in vivo model system, and the underlying mechanisms by which HBV-induced liver pathogenesis, and mechanisms by which HIV co-infection accelerate that process remain unknown due in large part to the lack of small animal models. Such model is crucial for the development of novel therapies, treating HBV/HIV-coinfections and associated liver diseases. There are several unresolved problems in mice co-transplanted with human hepatocytes and immune cells: transplantation of mismatched by HLA genotypes hepatocytes and hematopoietic stem cells contain a risk for allograft rejection and the low functionality of adaptive immune responses. We hypothesize that human hepatocyte transplanted mice, infected with HBV and co-transplanted with human HIV-1 infected or uninfected macrophages will reproduce the features of viral interaction. Methods: TK-NOG mice were transplanted with human hepatocytes, and after confirmation of the human albumin concentration in peripheral blood, animals were infected with HBV 107 GE/mouse (subtype D ayw ). Following confirmation of HBV DNA presence in peripheral blood (~1.5x10 4 copies/ml), animals were injected with human monocyte-derived macrophages (MDM) or HIV-exposed MDM (5x10 6 cells/mouse i.p.) and controls kept without MDM. Animals were observed for 51 days and levels of HIV RNA, HBV DNA, HBsAg in plasma were monitored. At end-point liver tissues were analyzed for histopathology, presence of viruses and human MDM by RT-PCR, and staining for human cells and viral proteins. Results: Multiphasic HBV viral kinetics – increase HBV DNA by day 13 and decline by day 51 in the presence of MDM, and exponential increase in HIV viral load were observed in the blood reaching steady levels at ~10 6 copies/ml by day 38. The plasma levels of HBsAg concentration also peaked at this point. Mice with HBV+HIV-MDM had higher content of HBV DNA, HIVgag RNA and human CD45 transcripts. Human hepatocytes in HBV infected mice showed strong expression of human HLA-DR, and proliferation. The plasma albumin concentration increased two folds in coinfected animals. Conclusion: This study utilizes a novel humanized mouse model which will fill the critical knowledge gaps on the mechanism by which HBV/HIV co-infection accelerates liver diseases and is the first model to observe changes in both viral replication pattern and tissue histopathology. 220 AN EARLY DECLINE IN HIV ANTIBODY BREADTH PREDICTS MORE RAPID DISEASE PROGRESSION Oliver Laeyendecker 1 , Kai Kammers 1 , Athena Chen 1 , Mariya V. Sivay 1 , Brandon Sie 1 , Tiezheng Yuan 1 , Divya Mohan 1 , Sanjay Kottapalli 1 , Tomasz Kula 2 , Charles

Poster Abstracts

78

CROI 2019