CROI 2019 Abstract eBook

Abstract eBook

Poster Abstracts

the increased morbidity and mortality of LRTI in HEU. To start addressing this question, we compared functional T cell responses, proportions of regulatory T cells (Treg), T cell differentiation and antigen presenting cell (APC) phenotypes in HEU and HU and assessed correlations between function and phenotypes. Methods: Peripheral blood mononuclear cells (PBMC) collected at 1-2 days of age from 59 HEU and cord blood PBMC from 17 HU were stimulated with Staphylococcal Enterotoxin B (SEB) or mock for 72h, and tested by flow cytometry for proliferation and expression of IFN ϒ , IL4, IL10, TGFβ, CD39 and CD107a. Treg, T cell differentiation and APC phenotypes were measured in unstimulated PBMC. Data were analyzed by univariate and multivariate linear regression adjusting for HIV exposure status. P-values were adjusted using false discovery rate. Results: HEU had significantly lower IFN ϒ , IL4, IL10, TGFβ and CD39 CD4+ T cell functional responses (SEB/mock) and similar CD8+ T cell responses. Phenotypic characterization of unstimulated PBMC revealed higher CD4+/CD8+FOXP3+, CD4+/CD8+FOXP3+CD25+ and CD8+IL10+ Treg and CD27- and/or CD28- differentiated conventional T cells and Treg in HEU vs HU. CD4+TGFβ+ and CD8+FOXP3+CD27+CD28+ naïve Treg were lower in HEU vs HU. HEU also had higher proportions of CD16+ intermediate monocytes; more CD16+ and CD16- conventional dendritic cells type 1 (cDC1); and higher expression of the CD103 inhibitory ligand on CD16- cDC1. Regression analyses adjusted for HIV exposure showed that higher CD8+IL10+ and CD8+FOXP3+ Treg in unstimulated PBMC were significantly associated with lower CD8+IFN ϒ +, CD8+CD107a+, CD8+CD39+ and/or CD8+IL4+ responses to SEB stimulation. There were no associations between T cell function and proportions of Treg in stimulated PBMC or between T cell function and T cell differentiation or APC phenotypes in PBMC . Conclusion: T cell responses to SEB were lower in HEU vs HU. Although HEU and HU had multiple T cell and APC phenotypic differences in SEB-stimulated and unstimulated PBMC, only high proportions of Treg in unstimulated PBMC were associated with decreased T cell function. 260 RNAPOL III CONNECTS RIG-I AND CGAS HIV-SENSING PATHWAYS IN DC FROM ELITE CONTROLLERS Enrique Martin-Gayo 1 , Ce Gao 1 , Zhengyu Ouyang 2 , Bruce D. Walker 1 , Mathias Lichterfeld 3 , Xu G. Yu 1 1 Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA, 2 University of California San Diego, San Diego, CA, USA, 3 Brigham and Women’s Hospital, Boston, MA, USA Background: HIV-1 elite controllers (EC) represent a small proportion of HIV- 1-infected individuals capable of naturally controlling HIV-1 replication in the absence of therapy, likely as a result of complex interactions between innate and HIV-1 specific immune responses. Recent data suggest that enhanced detection of cytosolic HIV-1 nucleic acids in conventional dendritic cells (cDC) from EC may depend on the activation of specific intracellular nucleic acid sensors and may trigger potent antiviral effector cell responses in these patients. Here, we investigated molecular mechanisms of effective detection of intracellular HIV-1 DNA in cDC from EC. Methods: Maturation of circulating cDC from n=22 EC and n=9 HIV negative individuals in response to nanoparticles loaded with HIV-1 Gag dsDNA probes was tested by flow cytometry. Subsequently, RNAseq characterization of transcriptional patterns in cDC from n=8 EC with different levels of response to in vitro stimulation was performed. Subsequent RNAseq analysis was also included using cDC from a larger cohort of HIV-1 controllers (n=23) and Progressors (n=14) was performed. siRNA-mediated gene silencing and Small inhibitors were used to validate the potential candidates predicted by our transcriptional study. Finally, analysis of single nucleotide polymorphisms (SNP) of selected candidate molecules was performed using public GWAS data. Results: Frequencies of activated cDCs responding to intracellular HIV-1 dsDNA were significantly higher in EC patients compared to healthy individuals (p<0.01), thanks to a subgroup of EC with markedly superior responses (good responders). Interestingly, transcriptional profiles of cDC from good DNA responders were characterized by differential upregulation of pathways associated with both DNA and RNA sensors. Surprisingly, cytoplasmic immune recognition of HIV-1 dsDNA was impaired after inhibition of RIG-I and RNA polymerase III (RNA pol III) to similar levels observed after cGAS knock down, suggesting that RNA pol III-dependent transcription of HIV-1 DNA allows simultaneous sensing of HIV-1 through cGAS and RIG-I pathways. Defined SNPs in transcripts encoding for RNA pol III and RIG-I were associated with improved innate immune recognition and immune control of HIV-1.

258 TELOMERE LENGTH, TELOMERASE ACTIVITY, AND AGE-RELATED DISEASE: ACTG NWCS 422 Chad J. Achenbach 1 , Drew Nannini 1 , Isabelle Clerc 1 , Hannah Hudson 1 , Brian Joyce 1 , Kunling Wu 2 , Katherine Tassiopoulos 2 , Peter W. Hunt 3 , Babafemi Taiwo 1 , Richard D’Aquila 1 , Sudhir Penugonda 1 , Lifang Hou 1 , Frank J. Palella 1 1 Northwestern University, Chicago, IL, USA, 2 Harvard University, Boston, MA, USA, 3 University of California San Francisco, San Francisco, CA, USA Background: Telomere length (TL) and telomerase activity (TA) require further study as biomarkers of age-related disease among persons with HIV (PWH). We assessed factors associated with short TL and associations between TL, TA and age-related co-morbidities among PWH on suppressive ART. Methods: A nested case-control study using clinical data and banked PBMCs from ACTG Longitudinal Linked Randomized Trials (ALLRT). Cases had: (1) sustained plasma HIV RNA (VL) suppression to <200 copies/mL within 24 weeks of ART initiation and for ≥96 weeks; (2) non-accidental death or confirmed diagnosis of cancer, cardiovascular, liver, renal, neurocognitive, or pulmonary disease, bone fractures or diabetes; (3) banked PBMC pre-ART, week 48 and pre-event. For each case, there were 2 controls matched for sex, age and duration of NRTI. TL was determined using qPCR with relative TL measured by quantifying a telomere repeat copy versus single copy reference gene ratio (T/S ratio). TA was determined using a real-time quantitative telomerase repeats amplification protocol (RQ-TRAP). TA data were log 10 transformed. Univariable and multivariable conditional logistic regression evaluated associations between TL, TA and disease. Results: We studied 351 participants (117 cases, 234 controls); 23% female, 53% non-white, 8% IDU and 56% smokers. Pre-ART, median age was 42 years, CD4 cells/µl 253, CD8 cells/µl 766, CD4/CD8 ratio 0.25, VL 4.7 log 10 copies/mL, TL 0.41 and TA 1.9 log 10 . Among incident cases, 14 (35%) were diabetes, 33 (28%) renal disease, 18 (15%) cancer, 14 (12%) CVD, 7 (6%) death and 4 (4%) bone fractures. Short pre-ART TL (<0.4 T/S ratio) was associated with pre-ART VL >10 5 copies/mL (OR=1.9; 95% CI 1.2-3.0) and pre-ART TA in the lowest quartile (OR 1.8; 95% CI 1.0-3.2). We found no associations between short pre-ART TL and age, smoking, CD4 or CD4/CD8 ratio. Factors positively associated with age-related disease were earlier calendar study entry year, pre-ART CD4<200 cells/µl, higher pre-ART VL, initial ART regimen without TDF, lower CD4/CD8 ratio at 96 weeks and smoking. Neither pre-ART TL nor TA were associated with age-related disease in univariable or multivariable analyses. Conclusion: Pre-ART telomeres were significantly shorter among PWH with higher VL levels; however, pre-ART TL and TA were not associated with age-related disease. Longitudinal data of changes in TL and TA during ART and associations with disease events are forthcoming. 259 HEU HAVE INCREASED PROPORTIONS OF TREG ASSOCIATED WITH DECREASED T-CELL FUNCTIONALITY Emilie Jalbert 1 , Kayla M. Williamson 1 , Miranda Kroehl 1 , Michael J. Johnson 1 , Marta Nunes 2 , Clare Cutland 2 , Shabir A. Madhi 2 , Adriana Weinberg 1 1 University of Colorado, Aurora, CO, USA, 2 University of the Witwatersrand, Johannesburg, South Africa Background: HIV-exposed uninfected infants (HEU) are at higher risk of lower respiratory tract infections (LRTI) that result in hospitalization and death compared with HIV-unexposed infants (HU). We have previously shown that antibody titers against respiratory pathogens do not differentiate HEU with and without LRTI, suggesting that decreased T cell responses may be responsible for

Poster Abstracts

93

CROI 2019