CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

Methods: HIV-DNA in tissues was quantified by single copy and multiplexed LTR/gag digital droplet PCR. Single genome sequences of proviral gag or pol were assessed by average pairwise distance (APD) (genetic diversity) and Slatkin-Maddison analyses. Proviral integration sites (IS) were obtained to assess diversity and clonal expansion rate/patterns; alpha (Simpson) and beta diversity (Bray-Curtis) indices were calculated to quantify intra- and inter-tissue diversity of clones. Results: Eight donors(median age = 50 y) expired from comorbid illnesses(5 neoplasms, 1 cardiac disease, 2 infection) underwent autopsy within 3-48 hours. HIV-DNA was present in all tissues with highest concentrations in lymph node (43-720 copies/1e6 cells), and lowest in brain (1-9 copies). HIV-LTR/gag quantification revealed diverse proviral structures with variable proportions of gag-deleted proviruses (0.1%-87.4%). Across tissues, proviruses harbored variable levels of hypermutations (6.2-44.4%) but were not compartmentalized (APD=0.2%-0.9%) and intermingled if hypermutated sequences were discarded. We obtained 914 IS from 3 donors with median (range) of 26 (3-163) IS per tissue. In 2/3 donors, clonal expansion rates were significantly different but not tissue-specific with 0-91.9% of clonal proviruses per tissue. Median (range) intra- and inter-tissue diversity indexes were 0.95 (0.53-0.1) and 0.93 (0.84-1) suggesting non-diverse but distinct proviral populations across tissues. In one donor with >15 tissues analyzed for IS, we observed significant difference in intra-tissue diversity between neoplastic and non-neoplastic (p=0.03) and in inter-tissue diversity between lymphoid vs non-lymphoid tissues (p=0.002). Conclusion: During therapy, HIV-infected cells are widely distributed in tissues but subject to differential pressures allowing the selection of proviruses with variable levels of defects and hypermutations. Clonal expansion significantly contributes to the proviral landscape. Our data suggests the role of local immune responses in shaping the anatomic proviral landscape. Impact of BACH2 on the Formation of HIV Latent Reservoirs in Humanized Mouse Model Hongbo Gao , Liang Shan Washington University in St Louis, St Louis, MO, USA Background: A pivotal challenge in achieving a cure for HIV is the limited understanding of the mechanisms governing the formation of latent reservoirs. Intriguingly, HIV integration site analysis studies have revealed unusually frequent integrations into the BACH2 gene. More importantly, inserted proviruses are nearly exclusively located upstream of the BACH2 start codon and share the same transcriptional orientation as the host gene, which leads to an increase in BACH2 transcription. The recurrent HIV-1 integration at the BACH2 locus and upregulation of the host gene expression suggest that BACH2 plays an important role in HIV reservoir seeding and maintenance. Methods: To investigate the impact of BACH2 on the HIV latent reservoir in vivo, humanized mice engrafted with BACH2 knockout (BACH2-KO) or control CD34+ cells were generated. Engrafted mice were infected with HIV followed by the administration of ART for six weeks. Subsequently, the frequency of tissue HIV DNA was assessed, and a portion of the splenic cells were transferred to immunodeficient mice for viral rebound analysis. In addition, we evaluated the influence of BACH2 on the conversion of CCR5 + CD4 + T cells into memory cells. Results: As expected, we observed a notable reduction in total B cells in mice reconstituted with a BACH2-KO immune system in comparison to the control animals. Concurrently, BACH2-KO group had a slight decline in the number of naïve T cells. Notwithstanding, BACH2 deficiency did not affect the quantities of CD4+ central and effector memory cells. In HIV-infected mice, the viral loads were comparable between the BACH2-KO and control groups. In mice on ART, a lower frequency of HIV DNA was observed in the BACH2-KO group. In splenic cell transfer experiments, a 100% rebound was detected in the control mice (5/5), contrasted by a 50% rebound (4/8) in the BACH2-KO group. Mechanistically, we found that BACH2-KO CCR5+ cells were unable to convert into long-lived central memory cells. Conclusion: Our study shows that BACH2 is required for the conversion of CCR5+ cells to central memory cells, and the formation of HIV reservoirs in long-lived central memory cells was abrogated in the absence of BACH2. Our study provides insight into the mechanisms underlying the establishment and stability of HIV latent reservoirs and identifies avenues for targeted interventions.

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Intact HIV Reservoir Levels Are Stable After Short-Term ART Interruption Prerana Shrestha 1 , Autumn Kittilson 1 , Meghan Melberg 1 , Evgenia Aga 2 , Ronald J. Bosch 2 , Jintanat Ananworanich 3 , Robert Coombs 4 , John W. Mellors 5 , Alan Landay 6 , Bernard J. Macatangay 5 , Steven G. Deeks 7 , Rajesh T. Gandhi 8 , Davey M. Smith 9 , Jonathan Z. Li 1 , for the AIDS Clinical Trials Group A5345 Study Team 1 Brigham and Women's Hospital, Cambridge, MA, USA, 2 Harvard TH Chan School of Public Health, Boston, MA, USA, 3 Thai Red Cross AIDS Research Centre, Bangkok, Thailand, 4 University of Washington, Seattle, WA, USA, 5 University of Pittsburgh, Pittsburgh, PA, USA, 6 Rush University Medical Center, Chicago, IL, USA, 7 University of California San Francisco, San Francisco, CA, USA, 8 Massachusetts General Hospital, Boston, MA, USA, 9 University of California San Diego, San Diego, CA, USA Background: As HIV cure remains a high priority for HIV research, analytical treatment interruption (ATI) in clinical studies remain vital to understand mechanisms for ART-free HIV remission. However, the impact of short-term treatment interruption on the intact HIV reservoir remains unclear. Methods: We evaluated participants who underwent treatment interruption as part of the ACTG A5345 trial. Participants had been on suppressive ART ≥2 years and comprised two groups: individuals who initiated ART during chronic infection (n=33) and during early infection (n=12). HIV reservoir levels were measured at three time points: pre-ATI, during the ATI and ~ 24 weeks of viral resuppression on ART (Step 3). We quantified levels of unspliced cell-associated RNA (CA-RNA), intact, defective, and total proviruses by the intact proviral DNA assay (IPDA). Residual viremia was measured by the integrase single-copy assay (iSCA). Wilcoxon rank-sum test was used for between-group comparison and Wilcoxon signed-ranks test for within-person comparison. Results: The median duration of ATI was 4 weeks in the study. Compared to the pre-ATI time point, levels of intact, defective, and total HIV DNA levels were significantly increased during the ATI for both the early and chronic-treated groups. Approximately 24 weeks after viral resuppression on ART, almost all levels of proviral measures (including intact and total HIV DNA) had returned to their baseline levels with no significant differences compared to the pre-ATI time point for both early and chronic-treated participants (Figure). Compared to pre-ATI, there was also no significant increase in CA-RNA levels 24 weeks after viral resuppression on ART. At all time points, levels of CA-RNA, intact, defective, and total HIV DNA levels were higher in chronic-treated compared to early-treated individuals. Early after ATI (median 1 week), higher levels of residual viremia by the iSCA was significantly associated with a shorter time to viral rebound ≥1000 HIV-1 RNA copies/mL amongst all participants (Spearman r = -0.60, p<0.01). Conclusion: Short-term ATI does not irreversibly change the reservoir size as reflected by stable levels of CA-RNA, or intact and total HIV DNA after viral resuppression. High-level viral rebound can be predicted by early signals of very low viremia. .

Poster Abstracts

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Clonal Expansion and Driving Forces of HIV-1 Persistence in Anatomic Compartments Annemarie Glassey 1 , Wenjie Wang 2 , Lindsey Adams 1 , Mary-Elizabeth Zipparo 1 , Robert Gorelick 3 , Stephen Hewitt 1 , Sharika Rajan 1 , Kathryn Lurain 4 , Ramya Ramaswami 4 , Chuen-Yen Lau 4 , Xiaolin Wu 2 , Sean Patro 2 , Thuy Nguyen 1 , Frank Maldarelli 1 1 National Cancer Institute, Frederick, MD, USA, 2 Leidos Biomedical Research, Inc, Frederick, MD, USA, 3 National Institutes of Health, Frederick, MD, USA, 4 National Cancer Institute, Bethesda, MD, USA Background: Upon infection, HIV quickly disseminates and establishes persistent infection throughout the body. The persistence mechanisms of HIV in tissues are complex, with viral and local environment interaction contributing to tissue-specific pathogenesis. To investigate the distribution of HIV populations in anatomic compartments, we characterized HIV-infected populations in tissues obtained at autopsy from individuals on suppressive therapy.

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