CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

445

Revealing the Role of Tissue-Resident NK Cells in HIV Infection Using Tissue Explant Models David Perea 1 , Nerea Sanchez Gaona 1 , Ana Gallego Cortes 1 , Stefania Landolfi 2 , Felix Pumarola 2 , Nuria Ortiz 2 , Ines Llano 2 , Juan Lorente 2 , Vicenç Falcó 2 , Meritxell Genescà 1 , María Buzón 1 1 Vall d'Hebron Research Institute, Barcelona, Spain, 2 Hospital Universitario de la Vall d’Hebron, Barcelona, Spain Background: Tissue-resident NK cells participate in immune clearance of tumor and infections, yet their response against HIV infection may vary across tissue microenvironments. Here, we characterized NK cells by their memory-like and residency properties, and assessed their functionality in killing HIV-infected cells in relevant tissue models of HIV infection. Methods: We obtained tissue resections from tonsils (n=38) and colons (n=32) from routine surgeries. Flow cytometry was used to quantify residency markers (CD49a, CD69, CD103), the memory-related marker NKG2C, and Killer-cell immunoglobulin-like receptors (KIRs) (KIR2DL1, S1, L2, L3, S2). Additionally, we measured natural cytotoxicity (CD107a, IFN-γ) after coculturing tissue cells with HLA-negative K562 cells in suspension, 2D coatings and 3D gels with collagen I and IV. Using tonsil and colon explants, we additionally characterized NK cells following ex vivo HIV(BaL) infection for 5-7 days. Results: Both tissues shared similar NK cell residency patterns, predominantly CD16-CD69+. Among these, CD49a-CD103- and CD49a+CD103+/- subpopulations exhibited the highest and lowest preactivation levels, respectively (median % of CD107a+IFN-γ- in tonsil: 70.60% vs 9.26%; colon: 77.90% vs 18.35%). However, robust natural cytotoxicity was exclusive to tonsillar NK cells, with CD16-CD49a+ "adaptive" (KIR+NKG2C+) cells showing a median 9.85-fold higher CD107a+IFN-γ+ cells upon stimulation. Of note, we observed that coculture on 2D coatings with collagen I or IV increased the IFN-γ in this subset, and K562 killing in 3D collagen I was enhanced in both tissues (tonsil: 1.75-fold; gut: 1.37). After 5-7 days of HIV infection, tonsils exhibited 10% more KIRs expression on CD16+CD69+CD49a+CD103- NK cells (p=0.032), yet the presence of CD69+KIRs+ NK cells correlated with lower levels of HIV infection (Fig. 1A). Conversely, in the colon, the CD16-CD103+ population significantly expanded (1.27-fold, p=0.001), correlating with reduced HIV infection levels when expressing NKG2C (p=0.017). Moreover, more CD16 CD69+CD49a-CD103+/- tonsillar NK cells were activated (% CD107a+IFN-γ-) after ex vivo HIV infection than in uninfected tissue explants, and CD16- KIRs+ and multiple resident NK cells showed increased CD107a expression upon K562 stimulation post-HIV exposure (Fig. 1B). Conclusion: This study underscores tissue-specific NK cell responses to HIV and their potential role in limiting HIV establishment in tissues, offering insights for future research and therapies.

(p=0.0125; r=-0.55). By the other hand, p24+ CD4+ T cells from PLWH showed higher expression of the TRAIL ligand DR4 than p24- CD4+ T cells. Finally, cytotoxic NK function against HIV-1 infected p24+ CD4+ T cells was abrogated in presence of an anti-TRAIL blocking mAbs, in contrast to anti- NKG2C and anti-NKG2D. Conclusion: In conclusion, cytotoxic function of memory-like NKG2C+ CD57- NK cells associated with good functional elimination of HIV-1 reservoir CD4+ T cells is mediated by TRAIL.

444

Single-Cell, Multi-Omics Analysis of SIV-Specific CD8 T-Cells Across Multiple Anatomical Sites Jennifer Simpson , Paul Schaughency, Justin Lack, Jason Brenchley National Institutes of Health, Bethesda, MD, USA Background: CD8+ T cells contribute to the antiviral response in simian immunodeficiency virus (SIV) infection in nonhuman primates. CD8+ T cells recognize viral epitopes via the T cell receptor (TCR). In previous studies, we examined the TCR repertoire of CD8+ T cells specific for a single SIV immunodominant epitope, Gag-CM9 (CTPYDINQM), throughout SIV infection. We identified tissue specific TCR sequences and TCRs shared by multiple anatomical sites. We now sought to evaluate if the tissue localization or TCR sequence of a CM9 specific CD8+ T cell corresponds with a transcriptional phenotype. Methods: CM9 specific CD8+ T cells were sorted from blood, lymph nodes, spleen, and liver from SIV infected rhesus macaques. The cells were processed through the 10x Genomics single cell sequencing protocol, creating a TCR amplified library and an RNA gene expression library for each cell. The sequenced libraries were demultiplexed and integrated using Cell Ranger and Seurat software. Clonotypes that reside within specific tissue specific and shared across multiple sites and clonotypes shared across multiple individuals (public) were identified. Results: Clustering analysis on the transcriptional profiles of CM9 specific CD8+ T cells revealed no obvious clustering by animal, or the presence of a public TCR sequence and minimal clustering was observed by tissue. Cells with tissue specific TCRs were most numerous in the liver. CM9 specific CD8+ T cells with a tissue specific TCR had higher expression of the tissue resident maker gene ITGA1. Multidimensional scaling analysis of CM9 specific CD8+ T cell transcription within the same tissue showed distinct distances between cells with shared and tissue specific TCRs in the blood, lymph nodes and liver. Interestingly, most of the transcriptional variation was captured by the spleen, rather than CM9 specific CD8+ T cells from peripheral blood. Conclusion: These data suggest that the tissue of origin of a CM9 specific CD8+ T cell, or the presence of a public TCR sequence does not associate with a distinct transcriptional profile across multiple anatomic sites. However, within the same tissue, whether a cell has a shared or tissue specific TCR sequence does appear to associate with a different transcriptional profile. Importantly, analysis of antigen specific CD8+ T cells from peripheral blood does not capture immunological phenomena occurring within tissues.

Poster Abstracts

446

Post-Intervention HIV Control Linked to Early In Vivo CD8+ T-Cell Proliferative Response to Rebound Demi A Sandel 1 , Michael J. Peluso 1 , Michiko Shimoda 1 , Lily Zemelko 1 , Alaa A. Latif 1 , Amelia N. Deitchman 1 , Gina Borgo 1 , Nitasha A. Kumar 1 , Meghann C. Williams 1 , Barbara K. Felber 2 , Gabriela Fragiadakis 1 , Matthew H. Spitzer 1 , Lillian Cohn 3 , Steven G. Deeks 1 , Rachel L. Rutishauser 1 1 University of California San Francisco, San Francisco, CA, USA, 2 National Cancer Institute, Bethesda, MD, USA, 3 Fred Hutchinson Cancer Center, Seattle, WA, USA Background: The mechanisms by which emerging immunotherapies (e.g., broadly neutralizing antibodies [bNAbs], vaccines) contribute to post-ART control are unknown. Robust HIV-specific CD8+ T cell proliferation (after in vitro peptide stimulation) has been consistently associated with sustained (elite) virus control. To determine the relevance of this relationship in vivo, we studied early T cell proliferation in response to reactivating virus in two prospective studies with an analytic treatment interruption (ATI).

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