CROI 2017 Abstract e-Book

Abstract eBook

Poster and Themed Discussion Abstracts

CD4+ T cells when compared with PBMCs stimulated with fecal bacteria from heterosexual men (p=0.001). Finally, stimulation of LPMCs with MSM-associated bacteria induced higher infection levels with HIV bal compared with LPMCs stimulated with fecal bacteria from heterosexual men (p=0.008). Conclusion: Our data support previous findings of gut microbiome compositional differences between MSM and heterosexual men, and suggest that microbiota of MSMmay play a role in increasing their risk to HIV infection by inducing immune activation. 208 FECAL MICROBIOTA FROM HIV-INFECTED SUBJECTS INCREASES IMMUNE ACTIVATION AND INFECTION Charles P. Neff , Sam Li, Abigail Armstrong, Catherine Lozupone, Brent E. Palmer Univ of Colorado, Aurora, CO, USA Background: High-throughput sequencing of 16s rRNA has shown compositional divergence of gut microbiota mediated by HIV and high risk behavior that often persist with Antiretroviral Therapy (ART). Here we further characterize the gut microbiota composition by disease status, ART and gender, and isolate fecal bacteria to evaluate the consequences of these changes in gut microbiota on immune activation and HIV infection of lamina propria T cells. Methods: Using 16S rRNA sequencing we have examined fecal microbiota composition of 210 individuals with and without HIV infection. To explore immune-modulatory properties of these bacteria, we isolated the whole fecal bacterial community by density gradient. We then enumerated the isolated bacterial community and verified that it closely resembles the composition of the original fecal sample. We then measured the impact of the bacterial community isolated frommen and women with or without HIV infection on peripheral blood and lamina propria mononuclear cells (PBMC and LPMC) by measuring T cell and myeloid cell activation and the impact of these bacterial communities on HIV infection. Results: Within our cohort the majority of HIV+ subjects harbor a Prevotella-rich/Bacteriodes-poor fecal microbiome in contrast to low risk HIV- subjects and interestingly HIV+ women had compositional changes that were distinct frommen. PBMC stimulated with fecal bacteria from HIV+ compared to HIV- subjects induced significantly higher levels of activated CD4 (p<0.0001) and CD8 (p<0.0001) T cells, macrophages (p=0.008) and dendritic cells (p=0.029). TLR2 blockade inhibited this activation (p=0.05). T cell activation was higher when cultured with fecal bacterial communities from untreated HIV+ subjects compared to those on ART (CD4 p=0.0009, CD8 p=0.009) or HIV+ females. LPMCs stimulated with fecal bacterial communities from HIV+ subjects induced higher levels of activated CD4 (p<0.0001) and CD8 (p<0.0001) T cells and increased HIV-infection of CD4+ T cells compared to normal fecal microbiota, indicating that the HIV associated gut microbiota may promote disease progression. Conclusion: This study provides important insight regarding the consequence of the alterations in gut microbiota associated with HIV infection. These data suggest that fecal bacterial communities associated with HIV infection increase immune cell activation and infection which could potentially drive disease progression. 209 MARAVIROC INHIBITS HIV TARGET T-CELL TRAFFICKING INTO THE FEMALE GENITAL LUMEN Alison S. Kohlmeier 1 , Sean McMaster 2 , Jessica Radzio 1 , Mian-er Cong 1 , Chuong Dinh 1 , Amy Martin 1 , Jacob E. Kohlmeier 2 , Gerardo Garcia-Lerma 1 1 CDC, Atlanta, GA, USA, 2 Emory Univ, Atlanta, GA, USA Background: Maraviroc (MVC) is an HIV entry inhibitor currently being tested in clinical studies for daily pre-exposure prophylaxis (PrEP) to prevent HIV infection. In contrast to currently approved PrEP drugs that interfere with HIV reverse transcription, MVC prevents infection by blocking the binding of HIV to CCR5 present on the surface of the target host cells, thus raising questions about potential immunological effects independent of its antiviral activity. We investigated the effect of daily oral MVC on CD4 T cell localization in the genital lumen of pigtail macaques and how these effects are influenced by the phase of the menstrual cycles. Methods: MVC was administered orally over a course of 5 days in pigtail macaques (n=6) during the follicular or luteal phase of the menstrual cycle (estimated fromweekly plasma progesterone levels). Immune characterization of CD4 T cells enriched from blood or cervicovaginal lavage was performed using flow cytometry and compared using a two-tailed t test. To investigate CCR5-mediated trafficking into the genital lumen, CD4 T cells from CCR5 knockout (KO) and wild type (wt) mice were isolated and intravenously transferred at equal ratios into RAG KO host mice. 2 weeks post transfer tissues were measured for the absolute numbers of transferred cells using flow cytometry. Statistics calculated by two-way ANOVA. Results: Increased plasma progesterone during the luteal phase of the menstrual cycle associated with both an increased frequency of CCR5 expression and chemotaxis on circulating memory CD4 T cells, and a higher frequency of migratory memory CD4 T cells resident at the genital lumen. To determine how CCR5 signaling may influence CD4 T cell localization at the genital lumen we employed a dual adoptive transfer approach, and found that CD4 T cell steady state trafficking into the genital lumen required CCR5 signaling (p=<0.0001). MVC treatment led to reduced detection of luminal CD4 T cells during the luteal phase of the menstrual cycle (p=0.0049), while no change in CD4 T cells was detected at the follicular phase (p=0.3) or during placebo treatment (p=0.6). Conclusion: Our results provide new insights into the mechanisms that may explain increased susceptibility to SHIV infection during the luteal phase of the menstrual cycle. Reductions in luminal CD4 T cells during the luteal phase due to MVC treatment demonstrate immunomodulatory effects of MVC that have the potential to decrease HIV infection risk. 210 INVESTIGATING THE EFFECT OF PH ON CERVICOVAGINAL MUCUS BARRIER PROPERTIES TO HIV Julie K. Shade , Thuy Hoang, Kevin Delong, Justin Hanes, Richard Cone, Laura Ensign The Johns Hopkins Univ, Baltimore, MD, USA Background: Bacterial vaginosis (BV) affects ~29% of women in the US and increases risk of HIV acquisition by 60%. “Healthy” vaginal bacteria communities are dominated by Lactobacilli, lactic acid (LA) producing bacteria that acidify vaginal secretions to pH 3.0-4.0. Women with BV have polymicrobial vaginal communities with few Lactobacilli and elevated vaginal pH (>4.5). We previously found that HIV virions were adhesively trapped in human cervicovaginal mucus (CVM) fromwomen with Lactobacilli-dominated microbiota. However, our recent unpublished work has found that HIV virions rapidly penetrate through CVM fromwomen with BV. We hypothesized this difference in CVM barrier properties may be due to elevated vaginal pH, and may partially explain the increased risk of HIV acquisition in women with BV. Methods: CVMwas self-collected by women ages 18-45. BV was diagnosed by meeting 3/4 of Amsel’s criteria and a Nugent score >7. Samples were serially alkalinized with 1M sodium hydroxide, and in some cases, re-acidified with hydrochloric acid (HCl) or LA. Internally fluorescently labeled mCherry-GAG HIV virions were added to CVM and movement of individual virions was assessed using a quantitative fluorescent microscopy technique. Results: Similar to our prior unpublished observations, HIV was highly mobile in CVM samples fromwomen with BV. Adhesive interactions (trapping) between HIV and CVM fromwomen with healthy microbiota were abolished when pH was increased > 5.18 ± .13. However, trapping of HIV, as measured by the % of mobile virions, was restored when neutralized CVM was re-acidified below pH 4.90 ± .37 (n = 7). The results were similar whether using HCl or LA for re-acidification. In contrast, acidification of CVM fromwomen with BV did not lead to trapping of HIV. Conclusion: Increasing the pH of CVM fromwomen with healthy vaginal microbiota led to a reduction in adhesive interactions with HIV virions, similar to what was observed in CVM fromwomen with BV. Re-acidification of neutralized CVM fromwomen with healthy microbiota restored adhesive interactions with HIV virions, an effect observed using both HCl and LA as the acidifying agent. However, acidification of CVM fromwomen with BV did not lead to trapping of HIV, suggesting that elevated pH alone is not enough to explain the reduced barrier properties of BV CVM to HIV. These findings may have important implications in the design of strategies to mitigate the increased risk of HIV infection associated with BV.

Poster and Themed Discussion Abstracts

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CROI 2017