CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

Methods: CD4+ T-cells were isolated from blood of 6 ART-suppressed HIV-2 infected individuals. Levels of cell-associated U3-U5 [Read-Through], initiated [TAR], 5'elongated [R-U5-pre-Gag], Gag, Nef, completed [PolyA] and multiply spliced [Tat-Rev] HIV-2 transcripts were measured by HIV-2 specific RT-ddPCR assays. U3-U5, TAR, R-U5-pre-Gag, Gag, and Nef HIV-2 DNAs were also quantified by ddPCR. For some individuals, primers and probes were matched to pre-existing proviral sequence data. Results: HIV-2 TAR DNA levels (median=1163 copies/1e6 cells) were similar to U3-U5 (1112) and were higher than R-U5-pre-gag (314), gag (211), and nef (86) HIV-2 DNA levels (P<0.04 for all). Levels of HIV-2 initiated transcripts (median=6339 copies/µg) were greater than 5'elongated transcripts (316; P<0.04). 5'elongated HIV-2 RNA levels were higher than Gag transcripts (median=71; P<0.04) and tended to be higher than Nef (13; P=0.063) and Poly A (4; P=0.063) HIV-2 transcripts. These trends persisted after normalization to the corresponding HIV-2 DNA regions. Ratios of 5'elongated/initiated HIV-2 RNAs (5'elongation) were higher than Gag/initiated (P<0.04) and Read Through/initiated (P<0.04). The ratios of 5'elongated/initiated (median=0.069) HIV-2 RNAs also tended to be higher than Nef/initiated (distal elongation, 0.0022) and PolyA/initiated (completion, 0.0015; P= 0.063 for both). We calculated that a median of 86% of HIV-2 transcripts are blocked at elongation, while 99% of transcripts are blocked at completion. Conclusion: Differences in the levels of HIV-2 transcripts and ratios suggest that HIV-2 expression is inhibited by blocks to elongation and completion of HIV-2 transcription. These mechanisms, which are also observed in HIV-1 infection, likely contribute to latent infection with both viruses. Future studies aimed at curing HIV-2 should focus on determining the cellular factors underlying these blocks to transcriptional elongation and completion. Variable Persistence of Non-Suppressible Viremia on Antiretroviral Therapy Elias K Halvas 1 , Evgenia Aga 2 , Ronald J. Bosch 3 , Christine Scello 4 , Sheldon Tetewsky 4 , Joshua C. Cyktor 1 , Joseph J. Eron 5 , Rajesh T. Gandhi 6 , Deborah K. McMahon 1 , John W. Mellors 1 1 University of Pittsburgh, Pittsburgh, PA, USA, 2 Harvard TH Chan School of Public Health, Boston, MA, USA, 3 Harvard University, Cambridge, MA, USA, 4 Frontier Science & Technology Research Foundation, Inc, Amherst, NY, USA, 5 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 6 Massachusetts General Hospital, Boston, MA, USA Background: Nonsuppressible viremia (NSV) on antiretroviral therapy (ART) has been shown to originate from infected T-cell clones rather than viral replication. The variation and longitudinal persistence of NSV have not been well defined. To address this knowledge gap, we enrolled a longitudinal cohort of persons with NSV on stable ART. Methods: We enrolled individuals living with HIV into a longitudinal ACTG cohort study of NSV who met the following inclusion criteria: At least 2 HIV-1 RNA values ≥20 and ≤1500 copies (c)/mL within 24 months prior to entry, at least 1 documented HIV-1 RNA value ≥20 and ≤1500 c/mL within 12 months prior to entry and on uninterrupted ART for at least 12 months. Persistence of NSV was categorized into three groups among those without ART changes or interruptions using RNAs at week 0 (entry), week 24, 48 (all 3 required): 1) all RNAs <40 c/mL, 2) mix of RNAs <40 and ≥40 c/mL, and 3) all RNAs ≥40 c/mL. Analyses of participant characteristics at study entry compared the 3 groups by age, sex, gender, pre-ART plasma HIV-1 RNA (log 10 c/mL), pre-ART and entry CD4+ T-cell count (cells/mm 3 ), entry CD8+ T-cell count (cells/mm 3 ), entry CD4:CD8 ratio, years on ART at entry, and the proportion of RNAs ≥40 c/mL during 24 months on ART prior to entry Results: 22 participants were analyzed: 1 (5%) female; median age 58 (range 24-75); median years on ART 9.5 (range, 2.9-26.8). The reported pre-study duration of NSV ranged to 10+ years. At week 48, 8 of 22 (36%) still had quantifiable viremia (≥40 c/mL). Only 3 (14%) participants had RNA ≥40 c/ mL at weeks 0, 24 and 48; 10 (45%) had RNA <40 c/mL at all three weeks and 9 (41%) had mix of <40 and ≥40 c/mL. The median pre-ART CD4 T-cell count for groups 1, 2 and 3 were 98, 121 and 164 cells/mm 3 , respectively. The only factor significantly associated with persistence of NSV ≥40 c/mL was the proportion of plasma HIV RNA measurements that were ≥40 c/mL during the 24 months on ART prior to entry (p=0.001, Kruskal-Wallis Test) (Figure). Conclusion: NSV was dynamic and consistently ≥40 c/mL at 0-48 weeks in only 14% of participants. Persistence of NSV over 48 weeks was only associated with the proportion of RNAs ≥40 c/mL prior to entry. These results are consistent

with variable persistence of clones producing virus with the minority being stable, and the majority declining in size and/or producing less virus.

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Different Impact of Latency Reversal in Cells From People With HIV Viremia and With ART Suppression Remi Fromentin 1 , Amélie Pagliuzza 1 , Hiroshi Takata 2 , William Brantley 2 , Benjamin Varco-Merth 2 , Afam A. Okoye 2 , Lydie Trautmann 3 , Nicolas Chomont 1 1 Centre de Recherche du CHUM, Montreal, Canada, 2 Oregon Health and Sciences University, Portland, OR, USA, 3 US Military HIV Research Program, Silver Spring, MD, USA Background: Induction of viral transcription using latency reversing agents (LRAs) is a promising approach to reduce the HIV reservoir but has shown modest effects in virally suppressed people with HIV (PWH) on ART. The administration of LRAs at the time of ART initiation may enhance the efficacy of this approach, since latently infected cells may be more sensitive to latency reversal in a viremic setting. However, the effect of LRAs on infected cells isolated from untreated PWH is largely unknown. Here, we compared the effect of the ingenol-based PKC agonist GSK445A alone or in combination with the HDACi romidepsin (RMD) on HIV transcription in cells from viremic and virally suppressed individuals. Methods: We measured the effect GSK445A +/- RMD on HIV transcription in CD4+ T cells isolated from the blood of 10 PWH on ART with undetectable plasma viral load as well as in 18 untreated individuals (median = 3.31x10 5 HIV RNA copies/mL). CD4+ T cells were conditioned or not for 4h with RMD (40nM) and pulsed for 30min with GSK445A (5nM) in the presence of antiretroviral drugs. HIV transcription was assessed 18h post-stimulation by RT-qPCR for cell-associated LTR-gag RNA. Results: As expected, the addition of RMD enhanced the GSK445A-mediated induction of HIV transcription in cells from ART-suppressed PWH (mean fold change over GSK445A alone 35.4, p=0.06). In cells from viremic participants, stimulation with GSK445A also led to a robust induction of HIV transcription (mean fold change 4.1, p<0.0001). However, the addition of RMD inhibited the induction of HIV transcription mediated by GSK445A (mean fold change 0.62, p=0.0003). To determine whether this apparent decrease could be attributed to the death of infected cells upon latency reversal, we used the pan-caspase inhibitor Q-VD-OPh 20µM. Inhibition of apoptosis not only rescued but also enhanced the levels of HIV transcripts measured in cells from viremic participants (mean fold increase in HIV RNA 2.1). Conclusion: The combination of GSK445A and RMD leads to an apparent reduction in the levels of HIV transcripts in cells isolated from viremic PWH. This decrease is abrogated by a caspase inhibitor, suggesting that latency reversal in a viremic setting leads to the death of the infected cells. Our results suggest that the administration of LRAs at the time of ART initiation, when the bulk of the reservoir is established, may reduce the frequency of persistently infected cells. Strong Latency Reversal by C. megalobotrys Extract in ART-Suppressed PBMC and Humanized Mice Khumoekae Richard 1 , Zhe Yuan 1 , Riza Kuthu 1 , Emery T. Register 1 , Paridhima Sharma 1 , Brian N. Ross 1 , Pau Zuck 2 , Carol Cheney 2 , Jessicamarie Morris 1 , Guoxin Wu 1 , Karam Mounzer 3 , Kerstin Andrae-Marobela 4 , Ian Tietjen 1 , Luis J. Montaner 1 1 Wistar Institute, Philadelphia, PA, USA, 2 Merck & Co, Inc, Kenilworth, NJ, USA, 3 Philadelphia FIGHT, Philadelphia, PA, USA, 4 University of Botswana, Gaborone, Botswana Background: Latency reversing agents (LRAs) have had limited success in vivo, indicating a need for more potent agents. "Mukungulu," an extract prepared from the bark of Croton megalobotrys and traditionally used for HIV/AIDS management in Northern Botswana (Africa), is an LRA in latent HIV cell lines and contains protein kinase C-activating phorbol esters (PMID: 28970153). However, the properties of Mukungulu ex vivo in ART suppressed cells from PLWH and/or in vivo are not known.

Poster Abstracts 473

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CROI 2024 122