CROI 2025 Abstract eBook

Abstract eBook

Poster Abstracts

Methods: 28 rhesus macaques (RMs) infected with SIVmac239 started antiretroviral therapy (ART) 42 days post-infection, maintained for 14-months. Rhesusized aIL-10 (n=10), aIL-10/aPD-1 (Combo therapy - n=10), or vehicle (n=8), infused every 3-weeks was administered starting 12 weeks pre-ATI and stopped 14-weeks post-ATI (week 26). Here, we utilized transcriptomic and metabolomic data from PBMCs and LNs to decipher the mechanisms of VL control observed in aPD1+aIL10 treated RMs. Results: Week 12 (pre-ATI) PBMC and LN transcriptomic profiling of aPD1+aIL10 treated RMs revealed a significant enrichment of Bile Acid (BA) metabolism and synthesis characterized by elevated FXR levels and enhanced BA and BA salt synthesis. Concordantly, elevated metabolites (tauro-litho cholate sulfate, litho-cholate sulfate) mapping to primary and secondary BA metabolism were elevated in dual-treated RMs. Additionally, enhanced levels of Type I IFN production characterized by innate anti-viral restriction factors RFs (IRF1, IRF7, APOBECs, TRIMs) were elevated in aPD1+aIL10 treated RMs. Notably, we observed a positive correlation between BA synthesis and Type I IFN RFs. Importantly, both mechanisms were negatively associated with the magnitudes of SIV RNA/DNA and 2LTR circles measured in LN. Conclusions: Our data highlight that administration of combo therapy drives innate Type I IFN signaling characterized by an intact anti-viral response downstream of BA synthesis. Of note, we also observed several pathways mapping to FGF signaling which were negatively correlated with week 36 (post ATI) virological outcomes. FGF15 and its human ortholog FGF19 are gut-derived circulating hormone that represses hepatic BA synthesis. Combo (aIL10+aPD1) treated RMs inhibit FGF signaling. Altogether, these data highlight the interplay between FGF signaling, BA synthesis/signaling and IFN signaling/antiviral immunity. These data also demonstrate that inhibition of FGF signaling could be used as an effective therapy. Activated Platelets Render Functionally Deficient Natural Killer Cells in People Living With HIV Brita Ostermeier 1 , Sanchita Pandey 2 , Carles Moreno Soriano 1 , Cheryl Clarkson Paredes 1 , Tomas Raul Wiche Salinas 3 , Gregory Cresswell 1 , Anastas Popratiloff 1 , Mirko Paiardini 3 , Sanjay B. Maggirwar 1 1 George Washington University, Washington, DC, USA, 2 University of Pennsylvania, Philadelphia, PA, USA, 3 Emory University, Atlanta, GA, USA Background: Anti-retroviral therapy (ART) for people with HIV (PWH) is very effective in suppressing HIV replication and preventing disease progression. However, even while on ART, NK cells remain dysfunctional. Although the exact mechanism of this dysfunction is unknown, there is evidence of increased platelet-immune cell complex formation in PWH. These complexes alter immune cell functions, which could play a role in NK dysfunction. We propose another role of platelets during HIV infection through platelet-NK cell complexes (PNKCs). We predict that PNKCs are a key factor in promoting NK dysfunction during HIV infection. Methods: PBMCs isolated from people without HIV (PWOH) and PWH (Table 1) and in vitro platelet-NK co-cultures were stained by flow cytometry with markers for platelets and NK cells. PNKCs were also identified in vitro via correlative light and electron microscopy (CLEM). We followed NK cells co cultured with platelets or platelet factors over 14 days, testing the NK killing capacity against target cells. Furthermore, Rhesus macaques (RMs) were treated with vehicle (n=5) or inclacumab, (n=5) at week -1 and week 2 post-infection and infected with SIV on day 0. PBMCs from days -28, 7, and 21, and at necropsy (days 32-39) were co-cultured with K562 in flow-based killing assays. Statistical significance was determined using Mann-Whitney t-tests with a p-value of <0.05. Results: Our studies indicate that PWH have increased levels of PNKCs compared to PWOH, which persists regardless of the NK subset, biological sex, or age. In PWH, PNKCs have higher expression of CD314 and CD25 compared to non-PNKCs, as well as higher expression of CD69, and lower expression of CD335 compared to PNKCs from PWOH. In vitro, NK cells exposed to platelet and platelet factors have increased effector function markers by day 7, which reverses by day 14. NK cells exposed to platelets also have altered killing capacities that vary depending on the target cell. In vitro data was validated by in vivo studies in RMs, where inclacumab treatment alleviated NK dysfunction. Conclusions: This study identifies elevated PNKCs in PWH, which have altered phenotypes compared to non-PNKCs and PNKCs from PWOH. In vitro , platelet-NK co-cultures confirm the formation of PNKCs, and both in vitro and in vivo studies implicate platelets as drivers in NK dysfunction. These results have important

consequences on future immune cell therapeutics in which the inclusion of platelet inhibitors may enhance cure outcomes.

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Elevated Lymph Node Metabolic Activity During Long-Term Antiretroviral Therapy Chuen-Yen Lau, Mahathir Khan, Jessica Earhart, Govind Nair, Esther Mena, Frank Maldarelli National Institutes of Health, Bethesda, MD, USA Background: Increased immune activation during antiretroviral therapy (ART) is associated with morbidity and mortality in persons with HIV (PWH). Mechanisms of elevated inflammation are uncertain but may include expression from HIV proviruses or dysregulated immune responses. Immune activation is often associated with increased metabolic activity in lymphoid organs, and can be detected non-invasively by 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT). Early PET studies did not detect increased metabolic activity in lymphoid tissues during ART. We investigated whether new, more sensitive FDG PET/CT approaches detect metabolically active lymphoid tissues during ART. Methods: Otherwise healthy PWH on ART with HIV RNA<20 c/ml for >3 years (y) underwent research time-of-flight FDG PET/CT using the Siemens Biograph mCT. Scans were analyzed using Medical Image Merge Software (MIM®). Cervical, mediastinal, axillary, and inguinal lymph nodes were identified manually and verified by a board-certified Nuclear Medicine radiologist. Metabolic activity in lymph nodes was quantified as standardized uptake value (SUV). Numbers of lymph nodes with 18F exceeding established threshold for normal uptake (SUVmax > 2.5) were quantified; SUVmax, total lesion glycolysis, and total lymph node volume were analyzed with descriptive parametric statistics. Results: Four males (mean age 62, range 42-83) y, undergoing ART for mean 21 (range 5-31) y, with median CD4 560 (range 402-590) cells/ µ L), underwent PET/CT; 7-32 nodes/PWH were evaluated. Metabolically active lymph nodes were identified in cervical, mediastinal, axillary, and/or inguinal regions in all participants; ≥ 3 lymph nodes with SUVmax > 2.5 were identified per PWH. Mean SUVmax was 3.8 (0.9-11.2). Total lymph node volume was similar for nodes with SUVmax<2.5 [0.21 (0.004-0.9) mL] and SUVmax>2.5 [0.25 (0.01 1.13) mL] (p=0.2091). Mean total lesion glycolysis was lower for nodes with SUVmax<2.5 [0.26 (0.01-1.3)] vs SUVmax>2.5 [0.73 (0.03-3.4)] (p=0.0015). Anatomic locations of elevated activity varied among participants; no clinical or laboratory findings explained the abnormal uptake. Conclusions: New PET imaging approaches localize elevated metabolic activity in lymph nodes of otherwise healthy PWH on long-term ART. While uptake varies significantly, nodal volumes do not. Non-invasive functional imaging will facilitate targeted evaluation of lymphoid tissues to determine mechanisms of immune activation during ART. Immunometabolism of Innate Lymphocytes in People Living With HIV-1 Versus HIV-2 Maryam Khan 1 , Claire Pardieu 1 , Athavan Umaipalan 2 , Hafiza Rahman 3 , Helena Miras 3 , John Thornhill 1 , Sarah Rowland-Jones 4 , Jane Deayton 1 , Sian Henson 1 , Chloe Orkin 1 , Neil McCarthy 1 , for the SHARE Collaborative 1 Queen Mary University of London, London, UK, 2 Barking, Havering and Redbridge University Hospitals NHS Trust, London, UK, 3 Barts Health NHS Trust, London, UK, 4 University of Oxford, Oxford, UK Background: HIV-2 is characterised by more indolent clinical progression than HIV-1, including decreased T-cell activation and limited immune exhaustion. However, it remains unclear how HIV subtypes impact the unconventional lymphocyte compartment, including mucosal-associated invariant T-cells

Poster Abstracts

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CROI 2025