CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

sorted peripheral CD4+ T cells showed a significant reduction in pathways of T cell activation, immune exhaustion (e.g.,PD-1), and cell cycling. While overall we did not observe a significant reduction in the HIV reservoir size after canakinumab, among 6 "virologic responders" (median -33% decrease in HIV total DNA copies/10 6 peripheral CD4+ T cells) we observed enhanced plasma IFN-β along with decreased expression, by CyTOF, of PD-1 on CD8+ T cells and Ki67 (a marker of cell cycling) on CD4+ T cells compared to 4 "non-responders" (no change in HIV total DNA). Single cell sequencing revealed significantly lower levels of the exhaustion markers (TOX, TIGIT and LAG3) in CD8+ T cells in virologic responders, although levels of granzyme and perforin were similar between groups. Conclusion: Our multiomic analysis highlights three potential novel mechanisms to target HIV after in vivo IL-1β blockade: (1) augmenting antiviral immunity, (2) enhancing cytotoxic CD8+ T cell effector function, and (3) reversing dysregulated immune activation of CD4+ T cells. Thus, IL-1β, via a multi-faceted approach, may induce an immunologic milieu favorable for HIV reservoir clearance. The figure, table, or graphic for this abstract has been removed. Elevated Plasma IL-10 and Type I Interferon Predict Faster HIV Reservoir Decay in Acute Treated HIV Lei Shi 1 , Junzhe Shao 1 , Sannidhi Sarvadhavabhatla 2 , Maria Sophia B. Donaire 2 , Alton Barbehenn 2 , Rebecca Hoh 2 , Gregory M. Laird 3 , Frederick Hecht 2 , Christopher Pilcher 2 , Timothy J. Henrich 2 , Jingshen Wang 1 , Jeffrey A. Tomalka 4 , Rafick P. Sekaly 4 , Steven G. Deeks 2 , Sulggi A. Lee 2 1 University of California Berkeley, Berkeley, CA, USA, 2 University of California San Francisco, San Francisco, CA, USA, 3 Accelevir Diagnostics, Baltimore, MD, USA, 4 Emory University, Atlanta, GA, USA Background: The HIV reservoir largely consists of "defective" virus, but the elimination of the "intact" (replication-competent) reservoir is a major focus of HIV eradication strategies. There are limited data describing reservoir decay rates during the first few months of acute-treated HIV, nor the host immune responses that drive reservoir decay. We quantified plasma cytokine levels from >500 longitudinal samples from the UCSF Treat Acute HIV cohort to determine immunologic pathways that predict reservoir decay in people with HIV (PWH). Methods: Individuals diagnosed with acute (<100 days) HIV were enrolled between 2015-2020, immediately initiated on ART (tenofovir/ emtricitabine+dolutegravir), and followed monthly for the first 24 weeks of ART initiation. Frequencies of intact vs. defective provirus were quantified using the IPDA®. High-sensitivity multiplex plasma cytokine assays were performed from cryopreserved plasma samples (MesoScale Diagnostics). Multivariate nonlinear general additive models were adjusted for false discovery rate (FDR) using the Benjamini-Hochberg method. Results: Among 67 PWH diagnosed <100 days from HIV acquisition, we observed an initial rapid (<8 weeks) decay, followed by second slower (8-24 weeks) decay of both intact and defective HIV proviral DNA during the first 24 weeks of ART. Among 20 plasma cytokines assayed across these same longitudinal timepoints (weeks 0, 2, 4, 8, 12, 16, 20, 24), IL-10 and type I interferons (IFN-β) significantly predicted accelerated reservoir decay even after adjustment for initial CD4+ T cell count, pre-ART viral load, age, and timing of ART initiation. IL-10 was significantly associated with faster decay rates for intact, but not defective virus, during both phases of decay (5.74% and 1.32% increase in decay rate/week per unit-increase in IL-10, respectively). IFN-β was significantly associated with faster decay rates during the second decay phase (0.89% intact and 1.55% defective HIV DNA). Conclusion: Individuals with higher plasma IL-10 and type I IFN expression during the first 24 weeks of ART demonstrated accelerated HIV reservoir decay. These cytokines are well known to exert variable effects on the host immune response depending on stage of disease (e.g., favorable during acute but detrimental during chronic infection). Our findings add insight into the complexity of these pleiotropic cytokines and highlight the need for potential stage-specific targeting of these cytokines in future HIV cure strategies.

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Labelled High Affinity TCRs for Detection of HIV Epitopes on Infected Cells: How Low Can We Go? Zoe Wallace , Jonathan Chamberlain, Esra Guc, Praveen K. Singh, Lucy Dorrell Immunocore, Abingdon, United Kingdom Background: HIV proviruses persist in a non-productive state in CD4+ cells. There is no individual cell surface biomarker that uniquely identifies infected cells. However, some cells contain proviruses that are transcriptionally active and translationally competent, leading to expression of viral proteins and T cell epitopes. We used soluble affinity-enhanced T cell receptors (TCR) to investigate the level of expression of viral peptides presented by HLA class I molecules. Methods: We developed T cell receptors with picomolar affinity (pM) for an HIV Gag epitope presented by HLA-A*02:01 and incorporated either a biotinylation tag or Fc fragment to enable fluorescence imaging. CD4+ T cell lines or primary cells with varying HLA expression levels were pulsed with peptide or infected with HIV and analysed for expression of viral peptide-HLA complexes by total internal reflection microscopy (TIRF; single molecule epitope counting). Results: HIV Gag peptide-HLA complexes could be identified on peptide pulsed cells using a labelled TCR and TIRF microscopy. The signal/noise ratio was improved using the TCR-Fc format. T2 cells pulsed with a titration of peptide were then used to quantify pHLA copies/cell and determine the dynamic range of the assay (~10-200 pHLA/cell). pHLA could also be detected on the surface of HIV-infected HLA-A*02-transduced C8166 cells, albeit at copies/cell near the lower limit of detection of the assay. Similar results were obtained with primary CD4+ T cells infected in vitro with HIV. In parallel we showed that the same TCR, when used in a bispecific format (Gag x CD3) could eliminate infected C8166 cells at picomolar drug concentrations in a T cell redirection assay. Conclusion: An affinity-enhanced TCR targeting a Gag peptide successfully detected pHLA complexes on the cell surface down to ~10 copies/cell and could redirect killing of infected cells when used in a bispecific format despite low pHLA expression, demonstrating its high sensitivity to antigen. Further work is ongoing to develop flow cytometry applications using labelled high affinity TCRs with the potential to isolate HIV-infected cells ex vivo for further analysis. HIV T-Cell Immunity Predicts Intact Proviral DNA Decline in People Treated During Acute Infection Pien M van Paassen 1 , Alexander O. Pasternak 1 , Ninée V. Buchholtz 2 , Karel A. van Dort 1 , Michelle J. Klouwens 1 , Liffert Vogt 1 , Casper Rokx 3 , Tokameh Mahmoudi 3 , Cynthia Lungu 3 , Jori Symons 2 , Monique Nijhuis 2 , Jan M. Prins 1 , Neeltje Kootstra 1 , Godelieve J. de Bree 1 1 Academic Medical Center, Amsterdam, Netherlands, 2 University Medical Center Utrecht, Utrecht, Netherlands, 3 Erasmus University Medical Center, Rotterdam, Netherlands Background: Starting antiretroviral therapy (ART) during acute HIV infection (AHI) is known to limit damage to the immune system and lower the size of the viral reservoir. In light of HIV cure interventions, it is important to understand the longitudinal dynamics of the early host immune responses in relation to the viral reservoir size. Therefore, we investigated the viral reservoir size and HIV specific immune responses in participants of the Netherlands Cohort Study on Acute HIV Infection (NOVA study), who initiated ART immediately after diagnosis of AHI. Methods: Participants in the NOVA study diagnosed during Fiebig II-VI were included in the analysis (n=22). PBMC from leukapheresis at 24 and 156 weeks after initiation of ART were analyzed. Viral reservoir size was assessed by Intact Proviral DNA Assay and qPCR. HIV specific precursor T-cell responses after HIV peptide pool stimulation (Env, Gag, Nef, Pol) were determined by

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CROI 2024 134