CROI 2018 Abstract eBook

Abstract eBook

Poster Abstracts

activation and viral load in peripheral blood implicating pro-inflammatory enteric microbiota as a driver of disease progression. Collectively, these findings suggest that the enteric microbiome plays a role in HIV disease progression and that modulation of enteric microbiota may provide an effective treatment option. 253 ISOLATION OF TRANSLOCATING BACTERIA IN PROGRESSIVE SIV INFECTION OF RHESUS MACAQUES Jacob Flynn , Alexandra Ortiz, Jason Brenchley NIAID, Bethesda, MD, USA Background: Microbial translocation is commonly observed in HIV-infected humans and is a significant contributor to chronic immune activation and inflammation. In SIV-infected Asian macaques, translocation has been demonstrated to occur across the gastrointestinal barrier; however, translocating bacterial taxa are not representative of the gut microbiota, with Proteobacteria appearing to preferentially translocate. To fully characterize translocating bacterial populations, we isolated systemically translocating bacteria from chronically SIV-infected macaques and identified them subsequent to live culture. Methods: Liver, mesenteric lymph node, and spleen samples were taken aerobically and anaerobically during necropsy from fifteen, chronically SIV-infected rhesus macaques. Swabs were used on the chest/abdomen of necropsied macaques to sample the skin microbiome as a control for potential contamination. Due to a lack of SIV uninfected macaques being necropsied, samples from these have not been incorporated as a control at this time. Tissue samples were homogenized and plated on: a) Brain Heart Infusion, b) TSA+Tween 80, and c) TSA+5% Sheep’s Blood media under aerobic conditions, and d) Brucella Blood and e) CDC Blood media under anaerobic conditions. Isolates were grown at 37°C for 1-7 days, depending on observed density. Colonies were restreaked for pure cultures and identified using MALDI-TOF and 16S rDNA sequencing. Isolates found to be present in tissues but also in the skin microbiome from the same animal were eliminated from consideration. Results: Eighteen species have been identified thus far, 3 Proteobacteria (all from the family Enterobacteriaceae), 1 Actinobacteria (all Corynebacteriaceae), Conclusion: Although bacterial taxa have been shown to translocate across the gastrointestinal epithelium, translocating taxa do not mirror the composition of the gastrointestinal microbiome, suggesting that translocating bacterial taxa are enriched for motile taxa or are functionally altered. We intend to grow these isolates in the presence of intestinal homogenates and sorted immune cell populations from SIV infected and uninfected macaques in order to measure microbial growth and motility to determine how lentiviral infections may promote preferential translocation. 254 CIRCULATING (1 → 3)-Β-D-GLUCAN AS A MARKER OF MICROBIAL TRANSLOCATION IN HIV INFECTION VikramMehraj 1 , Rayoun Ramendra 2 , Cecilia Costiniuk 3 , Bertrand Lebouché 3 , Rosalie Ponte 1 , Réjean Thomas 4 , Jason Szabo 3 , Pierre Coté 5 , Roger LeBlanc 6 , Jean-Guy Baril 7 , Cécile Tremblay 7 , Nicole Bernard 1 , Don C. Sheppard 1 , Jean-Pierre Routy 1 1 McGill University Health Centre Research Institute, Montreal, QC, Canada, 2 McGill University, Montreal, QC, Canada, 3 McGill University Health Centre, Glen site, Montreal, QC, Canada, 4 Clinique Médicale l’Actuel, Montreal, QC, Canada, 5 Centre Hospitalier de l’Université de Montréal, Montreal, QC, Canada, 6 Clinique OPUS, Montreal, QC, Canada, 7 Centre de Research du Centre Hospitalier de l’Université de Montreal, Montreal, QC, Canada Background: HIV infection is linked to gut damage and translocation of microbial products into the systemic circulation contributing to immune activation. Bacterial products and host acute phase proteins such as LPS, LBP and sCD14 have been used as markers of microbial translocation in HIV infection; however the utility of fungal antigens for the detection of gut damage has not been defined. We therefore sought to determine the relationship of the fungal antigens (1 → 3)-β-D-glucan (βDG) and galactomannan with markers of microbial translocation, inflammation and disease progression in early (EHI) and chronic (CHI) HIV infection. Methods: A total of 101 participants without suspicion of fungal infection and/ or GI symptoms were assessed in a cross-sectional analysis, including 61 EHI, and 14 Firmicutes (35.7% Lactobacillaceae, 14.3% Streptococcaceae, 14.3% Enterococcaceae, 7.1% Aerococcaceae, 7.1% Eubacteriaceae, 7.1% Leuconostocaceae, 7.1% Planococcaceae, 7.1% Staphylococcaceae).

Poster Abstracts

252 FECAL MICROBIOTA FROM HIV-INFECTED SUBJECTS INCREASES INNATE IMMUNE ACTIVATION Charles P. Neff , Owen Krueger, Sam Li, Nichole Nusbacher, Jennifer M. Schneider, Abigail Armstrong, Catherine Lozupone, Brent E. Palmer University of Colorado Anschutz Medical Campus, Aurora, CO, USA Background: 16S rRNA sequence analysis has identified compositional divergence of the enteric microbiota of men who have sex with men (MSM) regardless of HIV status; however, in HIV-infected subjects bacterial translocation contributes to chronic immune activation and drives disease progression. To address if the enteric microbiome of HIV-infected individuals are particularly pro-inflammatory we developed methodology to purify whole fecal bacterial communities (FBC) and test their immunomodulatory properties using healthy PBMC. Methods: FBCs of 50 individuals with and without HIV infection were isolated by density gradient, enumerated by flow cytometry and verified for composition resemblance to the original fecal sample using 16S rRNA sequencing. The impact of the FBCs on immune cells in peripheral blood was assessed by measuring activation of T cells (HLA-DR and CD38) and monocytes (CD14 shedding and CD80), levels of soluble CD14 and cytokine production (TNF-α, IFN-γ, IL-6) and by blockade assays. Findings were correlated to ex vivo immune parameters. Results: We demonstrate that FBCs of HIV-infected subjects induce high levels of activated monocytes and T cells in vitro. Monocyte and T cell activation induced by FBCs correlated (p=0.0006, r=0.46). Blockade of Toll-Like Receptors (TLRs) implicated TLR2 as a primary mediator of activation (p<0.0001). FBCs from HIV+ subjects induced TNF-α secretion and TNF-α blockade ameliorated T cell activation (p<0.0001). FBC induced T cell activation was correlated with ex vivo T cell activation (p=0.008, r=0.42), viral load (p=0.004, r=0.78) and the abundance of two opportunistic pathogens: Terrisporobacter glycolicus (p=0.002, r=0.44) and Turicibacter sanguinis (p=0.003, r=0.42). Conclusion: This study provides insight into the consequence of the alterations in enteric microbiota associated with HIV infection on systemic immune activation. Our findings demonstrate that FBCs from HIV-infected subjects induce monocyte activation and TNF-α production through TLR signaling resulting in T cell activation. This T cell activation correlated with ex vivo T cell

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CROI 2018