CROI 2016 Abstract eBook

Abstract Listing

Poster Abstracts

285 Seminal Plasma Induces Inflammation and Enhances HIV-1 Infection in Cervical Explants Andrea Introini 1 ; AnnelieTjernlund 1 ; Stéphanie Boström 1 ; Bo Hejdeman 2 ; Anna Gibbs 1 ; Frideborg Bradley 1 ; Kristina Broliden 3 1 Karolinska Inst, Stockholm, Sweden; 2 Södersjukhuset, Stockholm, Sweden; 3 Karolinska Univ, Stockholm, Sweden

Background: Exposure of the female genital mucosa (FGM) to semen induces a local inflammatory response, characterized by increased expression of pro-inflammatory cytokines and leukocyte infiltration. Although this phenomenon has long been reported in humans, its mechanisms and implications for susceptibility to HIV remain elusive. Here we validated an ex vivo model of coitus to study the effect of seminal plasma (SP) on HIV transmission to the FGM. Methods: Specimens of cervix were obtained from hysterectomized patients (age 35-50). Samples of SP from healthy individuals (n=12) were pooled to replicate experiments. Polarized explants of ectocervical mucosa were exposed to SP diluted 1:1 or 1:3, or medium only, for 2, 4 or 12 hours, with or without the anti-inflammatory drug indomethacin. After washing, explants were cultured with medium for additional 12 hours. In situ apoptosis was evaluated using a TUNEL assay. Levels of protein and gene expression of pro- inflammatory and growth factors were measured in medium and tissue respectively. The chemotactic effect of explant-conditioned medium on peripheral blood leukocytes was assessed with a transwell assay and flow cytometry. Explants exposed to SP were infected with the CCR5-tropic variant HIV-1 BaL and viral replication was measured as p24 gag concentration in culture medium. Results: In comparison to control explants, exposure to SP resulted in: the absence or similar levels of apoptosis (n=3); increased levels of IL-1α, IL-6, TNF-α, CXCL1, CXCL8, CCL20, TGF-β1, CSF2, IL-7, and PTGS2 either as protein concentration in CM or gene expression, or both (n=7, p<0.05); 2-fold and 3-fold increased transmigration of neutrophils and monocytes respectively (n=4, p<0.05). Treatment with indomethacin did not affect the SP-induced changes in protein and gene expression. Explants exposed to SP productively supported HIV-1 replication, with a 2-fold increase in cumulative p24 gag production over 18 days of culture compared to donor-matched untreated explants (n=5, p=0.06). Conclusions: Exposure of human cervical explants to SP recapitulates the main features of the response occurring in the FGM upon coitus. The inflammatory nature of this response may explain the observed enhancement of HIV-1 replication. Our model can be implemented to investigate further the early molecular events underlying HIV-1 transmission to the FGM, in order to develop prevention strategies that target other determinants of infection in addition to the virus. 286 The Effect of Condomless Receptive Anal Intercourse on the Rectal Mucosa in MSM Colleen F. Kelley 1 ; JingYang 1 ; GregoryTharp 1 ; Kirk A. Easley 2 ; Mark Mulligan 1 ; Patrick Sullivan 1 ; Steven E. Bosinger 3 ; Rama Amara 3 ; for the Emory Center for AIDS Research 1 Emory Univ, Atlanta, GA, USA; 2 Emory Univ Rollins Sch of PH, Atlanta, GA, USA; 3 Yerkes Natl Primate Rsr Cntr, Emory Univ, Atlanta, GA, USA Background: Rectal HIV transmission is considerably more efficient than penile or vaginal exposure. However, it is not known how condomless receptive anal intercourse (CRAI) alters the rectal mucosal immune environment in HIV negative men who have sex with men (MSM). Methods: HIV negative MSM (n=41; median age 28) engaging in CRAI with an HIV negative partner underwent rectal biopsy via rigid sigmoidoscopy at two time points separated by at least 8 weeks: 1. After abstaining from CRAI for > 72 hours and 2. After engaging in CRAI < 24 hours prior. Men who had never engaged in anal intercourse (n=21; median age 24) were enrolled as controls. Peripheral blood mononuclear cells (PBMCs) and rectal mucosal mononuclear cells (RMMCs) were isolated for immunophenotyping and mitogen (PMA/ionamycin) stimulation experiments. For flow cytometry data, differences between groups were analyzed with repeated measures analysis using linear mixed effects modeling. For a subset of MSM and controls, RNA was extracted from tissue biopsies for Illumina RNA-Seq and differential expression was assessed using DESeq2 algorithm. Results: In RMMCs, there were no differences between MSM and controls in the percentage of memory CD4+ cells that expressed CCR5 or Ki67; however MSM had lower overall mean (±SEM) expression of CD38 on CD4+ cells (38.0±2.5 vs. 49.4 ±3.5%; p=0.01). MSM had elevated levels of Ki67 on memory CD8+ cells (ln 1.4±0.1vs. 1.0%±0.2; p=0.03) and stimulated CD8+ cells had greater production of IFNγ (55.6±2.8 vs. 41.3%±4.0; p=0.005) and TNFα (40.0±2.4 vs. 31.9%±2.9; p=0.04) compared to controls. By RNA-Seq, 54 genes were significantly different between MSMwho abstained for >72 hours and controls; an additional 32 unique genes were differentially expressed in MSM<24 hours after CRAI compared to >72 hours (0.5>Fold-change<1.5; q<0.05). Genes important in cell proliferation, tissue remodeling, and immune activation were upregulated among MSM. Conclusions: The rectal mucosa of MSM engaging in CRAI did not harbor higher levels of activated CD4+ cells (CD38+ or Ki67+) or CCR5 expression indicating no increase in HIV target cell availability. However, elevated levels of CD8+ cell proliferation (Ki67+) and production of IFNγ and TNFα upon mitogen stimulation support a pro-inflammatory mucosal environment. Our data suggests that repeated exposure to gut microbes, lubricants, douching, and/or semen during CRAI is associated with a pro-inflammatory mucosal phenotype that may influence rectal HIV transmission.

Poster Abstracts

287 Reduced Peripheral a4ß7+ CD4+ T Cells CorrelateWith Mucosal CD4+ T Cell Loss in AHI Alexandra Schuetz 1 ; Chayada Sajjaweerawan 1 ; Nittaya Phanuphak 2 ; Rungsun Rerknimitr 3 ; PonpenTantivayakul 2 ; Nitiya Chomchey 2 ; Merlin L. Robb 4 ; Robin Dewar 5 ; Mark de Souza 2 ; Jintanat Ananworanich 6 ; for the RV254/SEARCH 010 and RV304/SEARCH 013 Study Groups 1 US AFRIMS, Bangkok, Thailand; 2 SEARCH, Bangkok, Thailand; 3 Chulalongkorn Univ, Bangkok, Thailand; 4 US Military HIV Rsr Prog, Walter Reed Army Inst of Rsr, Silver Spring, MD, USA; 5 Frederick Cancer Rsr and Develop Cntr, Frederick, MD, USA; 6 Military HIV Rsr Prog, Bethesda, MD, USA Background: Intestinal CD4 + CCR5 + T cells are rapidly and profoundly depleted early during acute HIV infection (AHI) contributing to persistent systemic immune activation. The integrin homing receptor α4β7 is thought to play a major role in the propagation and dissemination of HIV-1. CD4 + T cells expressing high levels of α4β7 (α4β7 hi ) are CD45RO + and also express high levels of CCR5 and activation markers. Due to the difficulty monitoring intestinal CD4 + T cells we evaluated α4β7 as a predictive marker for the loss of intestinal CD4 + CCR5 + T cells during early AHI.

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CROI 2016