POSTER PRESENTATIONS Journal of Virus Eradication 2019; 5 (Supplement 3): 1–58 34 single copy assay (SCA), total HIV-1 DNA and cell-associated RNA (CA-RNA) from PBMC, intact proviral DNA (IPDA) from CD4+ T cells, and plasma levels of IL-1RA, IL-4, IL-10, IL-11, IL-13, CCL-22, and TGFβ. Exploratory cross-sectional analyses assessed the relationship between these cytokines and measures of HIV-1 persistence. Results: 98 participants (21 females) were evaluated with a median (IQR) age of 46 years (37, 53) and 6.7 (4, 8) years on suppressive ART. Plasma levels of IL-4 were associated with the levels of intact proviral DNA (r=0.37, p=0.009), and the other main Th2 cytokine, IL-13, showed a trend towards a positive association with intact proviral DNA (r=0.26, p=0.07) (Table 1). There was also a trend towards an association of IL-4 levels with SCA HIV-1 RNA (r=0.2, p=0.06) but not total HIV-1 DNA (r=0.14, p=0.18) or CA-RNA (r=0.16, p=0.14). IL-1RA, IL-10, IL-11, IL-13, CCL-22, and TGFβ were not significantly associated with plasma SCA (N=95), total HIV-1 DNA (N=95), CA-RNA (N=90), or IPDA (N=48). Conclusions: Th2 cytokines are associated with a higher frequency of intact proviral HIV-1 DNA but not total HIV-1 DNA, whereas cytokines including IL-10 were not associated with intact or total HIV-1 DNA. There was a weaker association of IL-4 with residual viremia, which likely arises from cells with intact proviruses. This demonstrates the value of measuring intact proviral HIV-1 DNA when evaluating the relationship between immune responses and the HIV-1 reservoir. While the mechanistic link between IL-4 and IL-13 levels and cells carrying intact proviruses is undefined, these findings suggest that the dampening effect of Th2 cytokines on Th1 and Th17 responses could promote persistence of the HIV-1 reservoir. PP 4.5 Marker of gut damage REG3α and microbial translocation are associated with integrated HIV DNA in CD4 T cells during early HIV infection S. Isnard 1 , F.P. Dupuy 1 , J. Lin 1 , B. Fombuena 1 , R. Ramendra 1 , J. Ouyang 1 , B. Lebouché 1 , C. Costiniuk 1 , C. Tremblay 2 , J.P. Routy 1 1 McGill University, Montreal, Canada, 2 Université de Montréal, Montreal, Canada Background: The impediment to an HIV cure lies in the early for- mation of HIV reservoirs, mostly consisting of CD4 T-cells carrying integrated HIV DNA in their genome. In addition to HIV itself, gut damage and microbial translocation fuels inflammation and HIV reser- voir size that is maintained in people living with HIV (PLWH) receiv- ing antiretroviral therapy (ART). Herein, we assessed the association of different gut damage and microbial translocation markers with integrated HIV DNA levels in early and chronically infected PLWH. Methods: Blood from ART-naïve PLWH in early infection (less than 6 months aſter the estimated date of infection, ART-, n=33) or people in chronic infection ART-treated (ART+, n=29) was collected. Integrated HIV DNA was measured by nested qPCR in sorted CD4 T-cells. Gut damage markers regenerating islet-derived protein 3α (REG3α), intestinal fatty-acid binding protein (I-FABP), and soluble suppressor of tumorigenicity 2 (sST2), as well as the bacterial marker lipopolysaccharide (LPS) were measured in plasma by ELISA. The fungal translocation marker β-D-glucan (BDG) was measured in plasma with the Fungitell ® assay. Results: Participants of the ART- group were infected for a median of 97 days with a viral load (VL) of 4,12 log 10 copies/mL. Participants in the ART+ group were infected for a median of 16 years, treated for 13 years, and had VL <50 copies/mL. In ART- PLWH, levels of REG3α, but not I-FABP nor sST2, correlated with VL (r=0.31, p=0.007) and integrated HIV DNA (r=0.42, p=0.02). None of these gut damage markers were associated with integrated HIV DNA in the ART+ group. In all study participants, REG3α correlated with LPS (r=0.24, p=0.004) and BDG (r=0.18, p=0.03). LPS and BDG were associated with integrated HIV DNA levels (r=0.35, p=0.04 and r=0.54, p=0.001 respectively) in ART- only but not in ART+. Conclusions: The gut damage marker REG3α was associated with VL and integrated HIV DNA in ART-naïve but not ART+ PLWH, in association with microbial translocation of bacterial and fungal products. In addition to HIV itself, gut damage and microbial trans- location fuel HIV reservoir size in early HIV infected individuals. These findings may help developing strategies to dampen reservoir formation in acute HIV infection. PP 4.6 BCL-2 antagonism sensitises CTL-resistant HIV reservoirs to elimination ex vivo R.B. Jones 1,3 , Y. Ren 1 , S.H. Huang 1 , S. Patel 2 , W.C. Alberto 1 , D. Magat 1 , D. Ahimovic 1 , A.B. Macedo 3 , A. Bosque 3 , C.M. Bollard 2 1 Infectious Diseases Division, Weill Cornell Medicine, New York, Ny, USA, 2 Childrens National Medical Center, Washington, DC, USA, 3 Dept of Microbiology, Immunology, and Tropical Medicine, George Washington University, Washinton, DC, USA Background: Curing HIV infection will require the elimination of a reservoir of infected CD4 + T-cells that persists despite HIV-specific cytotoxic T-cell (CTL) responses. While viral latency is a critical factor in this persistence, recent evidence also suggests a role for intrinsic resist- ance of reservoir-harboring cells to CTL killing. This resistance may have contributed to negative outcomes of clinical trials, where pharmacologic latency reversal has thus far not resulted in reductions in HIV reservoirs. Methods: RNA-seq was performed to identify genes that were dif- ferentially expressed in peptide-pulsed CD4 + T-cells that survived co- culture with HIV-specific CTL clones. Protein-level expression of putative drivers of resistance was measured in HIV-Gag + cells reactivated from long-term ART-suppressed individuals by ‘HIVFlow cytometry’, which targets two epitopes of Gag. HIV eradication (HIVE) assays were used to test ex vivo elimination of reservoir-harboring cells. Briefly, HIV- specific T-cells were co-cultured with ex vivo CD4 + T-cells, and changes in infected-cell frequencies were measured by droplet-digital-PCR - total HIV DNA, and QVOA - intact-inducible reservoir. Results: We identified 1,061 genes that were differentially expressed between survivor cells (HIV peptide-pulsed) and bystander cells (non- pulsed) following co-culture with a peptide-specific CTL clone (Padj < 0.05) - implicating 14 significantly enriched pathways (Ingenuity Pathway Analysis). Amongst these, we prioritized the pro-survival factor BCL-2 - over-expressed in surviving cells - for further study. We confirmed by flow cytometry that BCL-2 hi cells preferentially survived peptide-pulsed CTL-killing assays using ex vivo CD4 + T-cells. By ‘HIVflow’, we observed that the inducible HIV-reservoir in ARV- treated individuals was disproportionately present in BCL-2 hi CD4 + T-cells, following ex vivo re-activation. In HIVE assays, treatment with the BCL-2 antagonist ‘ABT-199’ alone was not sufficient to drive reductions in ex vivo viral reservoirs, when tested either alone, or with the latency reversing agent (LRA). However, the triple combi- nation of LRAs, HIV-specific T-cells, and ABT-199 uniquely enabled reductions in ex vivo reservoirs (p<0.01). Conclusions: Our Results: provide rationale for targeting resist- ance to CTL as a novel component of therapeutic strategies for reducing HIV reservoirs. We highlight BCL-2 antagonism as one potential target for such approaches, and present additional differ- entially expressed genes and pathways associated with survival for further study. PP 4.7 PD-1+ CD4 T cells are associated with HIV reservoir size and impaired function of T follicular helper cells in children and young adults on long-term viral control S. Rinaldi 1 , V. Dinh 1 , S. Pallikkuth 1 , L. De Armas 1 , R. Pahwa 1 , N. Cotugno 2 , E. Nastouli 3 , C. Foster 4 , P. Palma 2 , S. Pahwa 1 1 Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, USA, 2 Bambino Gesu Children’s Hospital, Rome, Italiy, 3 UCL Great Ormond Street Institute of Child Health, London, UK, 4 Imperial College Healthcare NHS Trust, London, UK