CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

CD4+ T cells carrying inducible, replication-competent proviruses. Current HIV cure strategies aim to delay or prevent viral rebound. Previously, we showed that autologous neutralizing antibodies (aNAbs) can prevent ex vivo outgrowth of some viruses in the latent reservoir of people with HIV (PWH; Bertagnolli et al., PNAS 2020) and that the reservoir remains stable for decades (McMyn et al., JCI 2023). However, it is not understood whether viruses persisting over long times on ART are sensitive to aNAbs. Methods: Using samples of outgrowth viruses from nine PWH on long-term ART for a mean of 22 years and four PWH on ART for 11 years, we generated HIV pseudoviruses with the env sequences of inducible, replication-competent outgrowth viruses. Pseudoviruses of viral variants from each person were incubated with contemporaneous aNAbs and tested in a TZM-bl-based neutralization assay. Viral variants were also tested against three clinically relevant broadly neutralizing antibodies (bNAbs) targeting different neutralizing epitopes. Results: Most outgrowth viruses from PWH on long-term ART were resistant to neutralization by aNAbs, with 85% of 34 isolates being resistant (IC 50 >100 ug/ mL). Conversely, PWH on ART under 20 years had more sensitive isolates (IC 50 : 3 to 99 ug/mL), as only 22% of 55 viral isolates were resistant to aNAbs (IC 50 >100 ug/mL). Viral isolates from both groups demonstrated similar sensitivities to the three bNAbs (VRC01, 10-1074, PGDM1400; IC 50 : <.03 to >10). 89% of PWH on long-term ART had all tested viral isolates sensitive to at least one bNAb and 56% sensitive to two bNAbs, while 100% of PWH on short-term ART were sensitive to at least one bNAb and 50% sensitive to two bNAbs. Conclusion: We demonstrated that in PWH on long-term ART, outgrowth viruses including large clones are more resistant to neutralization by aNAbs than proviruses induced in CD4+ T cells of PWH on ART for 11 years. This suggests a selection process may occur over two decades of ART. These aNAb resistant outgrowth viruses may contribute to viral rebound during treatment interruption, but this data may inform cure strategies with therapeutic vaccines that induce antibodies to neutralization-resistant viruses. Additionally, the large proportion of viral isolates sensitive to at least one bNAb could aid in the design of immunotherapy trials involving bNAbs. Immune Selection of HIV-1 Reservoir Cells After Early ART Initiation Weiwei Sun 1 , Gregory Gladkov 1 , Ce Gao 1 , Leah Carrere 2 , Isabelle Roseto 2 , Elizabeth Parsons 2 , Carmen Gasca Capote 1 , John Frater 3 , Sarah Fidler 4 , Xu G. Yu 1 , Mathias Lichterfeld 1 1 Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA, 2 Brigham and Women's Hospital, Boston, MA, USA, 3 University of Oxford, Oxford, United Kingdom, 4 Imperial College London, London, United Kingdom Background: HIV reservoirs are established shortly after infection, but little is known about immune effects that influence viral reservoir cell evolution in early-treated people living with HIV (PLH). Here, we analyzed the proviral landscape and phenotypic features of HIV reservoir cells in the RIVER study, a randomized-controlled study evaluating effects of a ChAd63-vectored therapeutic vaccine (HIV.consv) given prior to a histone deacetylase inhibitor, Vorinostat, in PLH started on ART at the time of acute/early HIV diagnosis. Methods: 10 RIVER study participants (n=5 from ART-only group, n=5 from the treatment group) were studied, using PBMC samples from randomization, the primary endpoint (18 weeks after randomization), and 1 year after study completion. Proviral landscapes were analyzed by near full-length proviral sequencing (FLIP-seq) and matched integration site and proviral sequencing (MIP-seq). Phenotypic and proviral sequencing (PheP-seq) was used to investigate the phenotype of memory CD4 T cells from 3 participants. Results: In total, n=2763 proviral sequences were detected from 122.03 million PBMCs in all 10 participants combined; n=295 sequences (10.68%) were genome-intact. The mean numbers of intact HIV proviruses from randomization, primary endpoint and 1 year follow-up were 6.27, 2.39, 8.84 per million PBMC in the ART-only group versus 4.42, 2.37, and 5.46 per million cells in vaccine group (p=n.s.). 138 integration sites (IS) of intact proviruses were identified; among these, 54 (39.13%) were located in non-genic DNA, centromeric satellite DNA and genes encoding for members of the Zinc Finger Protein family. The proportion of intact proviruses integrated in these heterochromatin regions increased during longitudinal evaluations from 26% at randomization to 54% at the 1-year follow-up timepoint, but did not differ between the study arms. A total of n= 116,023 individual mCD4 T cells were analyzed by PheP-seq: n=648 represented HIV-infected cells and n=128 cells harbored genome-intact HIV-1. Notably, HLA-G, HLA-F, HLA-C, CCR6 and TGFB-R

with sporadic cases in Europe, America and Canada. Previous works have demonstrated the limited number of therapeutic options due to the natural genetic polymorphisms associated with HIV-1 non-M. Thus, our work aimed to determine the in vitro susceptibility of these particular strains to Ibalizumab, a first-in-class long-acting CD4-directed post-attachment inhibitor.

502

Non-Invasive Imaging Identifies Elevated Metabolic Activity in Lymphoid Tissue During Long-Term ART Chuen-Yen Lau , Jessica Earhart, Danielle Konlian, Ariana Savramis, Thuy Nguyen, Corina Millo, Avindra Nath, Robert Gorelick, Ana Ortega-Villa, Michael Kassin, Elliott Levy, Brad Wood, Dima Hammoud, Frank Maldarelli, for the NIH Background: Mechanisms of HIV persistence in anatomic compartments remain poorly understood. Positron Emission Tomography (PET) is a non invasive technique that may provide insights to the spatial distribution and microenvironment of HIV persistence and identify sites for tissue sampling. Early 18F-fluorodeoxyglucose PET (FDG-PET) techniques did not detect elevated metabolic activity during long-term antiretroviral therapy (ART), though increased metabolic activity was observed with rebound viremia. To investigate whether new technologically advanced PET imaging with improved resolution detects metabolic activity in lymphoid tissues during long-term ART, we used FDG-PET co-registered with computed tomography (CT) followed by fusion guided lymph node biopsy to obtain samples for characterization. Methods: Participants recruited through NIH study NCT05419024 (Imaging and Biopsy of HIV-Infected Individuals Undergoing Analytic Treatment Interruption (ATI)) underwent FDG-PET-CT and FDG uptake was quantified as standardized uptake value (SUV; FDG uptake normalized to injected activity/weight). Tissue was sampled with ultrasound fusion guidance and aspiration. HIV RNA in plasma and cell-associated (CA) HIV DNA and RNA in cells from blood and lymphoid tissue were quantified by single copy assays (Somsouk et al., 2014). Results: Study participants (N=2; HIV RNA <50 copies/ml plasma for >3 y, CD4 562-590) underwent imaging and guided biopsy. Imaging noted lymph nodes were all ≤ 1cm diameter; although most nodes had minimal FDG signal, increased uptake was detected in c. 3-10 lymph nodes in both participants (SUVmax 1.14 - 6.4), indicating increased metabolic activity was present in these tissues. Metabolically active nodes were present in mediastinal, axillary and inguinal distributions. Nodes accessible to fusion guided sampling yielded 104-105 cells. Levels of HIV DNA in biopsies (610-900 HIV DNA copies/1e6 cells) were c. 5 -15-fold higher than levels in peripheral blood mononuclear cells (PBMC). HIV RNA was quantifiable in both nodal tissue and PBMC; levels of HIV RNA/DNA (0.4-1.2 RNA copies/DNA copy) were comparable in blood and nodal sampling. Conclusion: New non-invasive imaging approaches identify increased metabolic activity in subsets of lymph nodes during long term ART, and directed biopsy recovers sufficient HIV DNA and RNA for analysis even in nodes < 1cm size. Image guided approaches will advance understanding of HIV persistence in tissues. Inducible, Infectious HIV-1 Resistance to Autologous Neutralizing Antibodies After Long-Term ART Natalie F McMyn , Joseph Varriale, Hanna Wu, Janet M. Siliciano, Robert F. Siliciano The Johns Hopkins University School of Medicine, Baltimore, MD, USA Background: ART reduces HIV-1 viral loads below the detection limit, but ART cessation leads to rapid viral rebound due to a population of latently infected Biopsy and Treatment Interruption Team National Institutes of Health, Bethesda, MD, USA

Poster Abstracts

504

503

CROI 2024 132