Abacavir inhibits but does not cause self-reactivity to HLA-B*57:01-restricted EBV specific T cell receptors

Pre-existing pathogen-specific memory T cell responses can contribute to multiple adverse outcomes including autoimmunity and drug hypersensitivity. How the specificity of the T cell receptor (TCR) is subverted or seconded in many of these diseases remains unclear. Here, we apply abacavir hypersensitivity (AHS) as a model to address this question because the disease is linked to memory T cell responses and the HLA risk allele, HLA-B*57:01, and the initiating insult, abacavir, are known. To investigate the role of pathogen-specific TCR specificity in mediating AHS we performed a genome-wide screen for HLA-B*57:01 restricted T cell responses to Epstein-Barr virus (EBV), one of the most prevalent human pathogens. T cell epitope mapping revealed HLA-B*57:01 restricted responses to 17 EBV open reading frames and identified an epitope encoded by EBNA3C. Using these data, we cloned the dominant TCR for EBNA3C and a previously defined epitope within EBNA3B. TCR specificity to each epitope was confirmed, however, cloned TCRs did not cross-react with abacavir plus self-peptide. Nevertheless, abacavir inhibited TCR interactions with their cognate ligands, demonstrating that TCR specificity may be subverted by a drug molecule. These results provide an experimental road map for future studies addressing the heterologous immune responses of TCRs including T cell mediated adverse drug reactions

Single-cell analysis shows that adipose tissue of persons with both HIV and diabetes is enriched for clonal, cytotoxic, and CMV-specific CD4+ T cells

Persons with HIV are at increased risk for diabetes mellitus compared with individuals without HIV. Adipose tissue is an important regulator of glucose and lipid metabolism, and adipose tissue T cells modulate local inflammatory responses and, by extension, adipocyte function. Persons with HIV and diabetes have a high proportion of CX3CR1+ GPR56+ CD57+ (C-G-C+) CD4+ T cells in adipose tissue, a subset of which are cytomegalovirus specific, whereas individuals with diabetes but without HIV have predominantly CD69+ CD4+ T cells. Adipose tissue CD69+ and C-G-C+ CD4+ T cell subsets demonstrate higher receptor clonality compared with the same cells in blood, potentially reflecting antigen-driven expansion, but C-G-C+ CD4+ T cells have a more inflammatory and cytotoxic RNA transcriptome. Future studies will explore whether viral antigens have a role in recruitment and proliferation of pro-inflammatory C-G-C+ CD4+ T cells in adipose tissue of persons with HIV

Adipose tissue in persons with HIV is enriched for CD4+ T effector memory and T effector memory RA+ cells, which show higher CD69 expression and CD57, CX3CR1, GPR56 Co-expression With Increasing Glucose Intolerance

Chronic T cell activation and accelerated immune senescence are hallmarks of HIV infection, which may contribute to the increased risk of cardiometabolic diseases in people living with HIV (PLWH). T lymphocytes play a central role in modulating adipose tissue inflammation and, by extension, adipocyte energy storage and release. Here, we assessed the CD4+ and CD8+ T cell profiles in the subcutaneous adipose tissue (SAT) and blood of non-diabetic (n = 9; fasting blood glucose [FBG] < 100 mg/dL), pre-diabetic (n = 8; FBG = 100–125 mg/dL) and diabetic (n = 9; FBG ≥ 126 mg/dL) PLWH, in addition to non- and pre-diabetic, HIV-negative controls (n = 8). SAT was collected by liposuction and T cells were extracted by collagenase digestion. The proportion of naïve (TNai) CD45RO−CCR7+, effector memory (TEM) CD45RO+CCR7−, central memory (TCM) CD45RO+CCR7+, and effector memory revertant RA+(TEMRA) CD45RO−CCR7− CD4+ and CD8+ T cells were measured by flow cytometry. CD4+ and CD8+ TEM and TEMRA were significantly enriched in SAT of PLWH compared to blood. The proportions of SAT CD4+ and CD8+ memory subsets were similar across metabolic status categories in the PLWH, but CD4+ T cell expression of the CD69 early-activation and tissue residence marker, particularly on TEM cells, increased with progressive glucose intolerance. Use of t-distributed Stochastic Neighbor Embedding (t-SNE) identified a separate group of predominantly CD69lo TEM and TEMRA cells co-expressing CD57, CX3CR1, and GPR56, which were significantly greater in diabetics compared to non-diabetics. Expression of the CX3CR1 and GPR56 markers indicate these TEM and TEMRA cells may have anti-viral specificity. Compared to HIV-negative controls, SAT from PLWH had an increased CD8:CD4 ratio, but the distribution of CD4+ and CD8+ memory subsets was similar irrespective of HIV status. Finally, whole adipose tissue from PLWH had significantly higher expression of TLR2, TLR8, and multiple chemokines potentially relevant to immune cell homing compared to HIV-negative controls with similar glucose tolerance

Defining an adipose tissue single cell atlas to understand metabolic disease in HIV

Background: Adipose tissue (AT) is a critical regulator of metabolic health and is emerging as important in HIV. Despite this, data on the complex cellular milieu and immune regulation are lacking. We sought to assess the AT microenvironment in persons with HIV (PWH). Methods: We performed subcutaneous abdominal liposuction and isolated the stromal vascular fraction (SVF) from 16 HIV-negative diabetics, 16 HIV-positive non-diabetics and 16 HIV-positive diabetics on long-term ART. Cells were stained with a panel of 5’ DNA-sequence tagged antibodies (TotalSeq-C) that represented standard lineages, activation and regulatory markers (45 antibodies). For the analysis, CellRanger (version 3.0.0) was used to demultiplex the raw sequencing data, extract filter and correct barcodes and unique molecular identifiers, remove cDNA PCR duplicates and align reads to the human transcriptome (GRCh38). The resulting BAM files and filtered count matrices were used in analyses. We assessed the AT cell types and their association of these subsets with the preadipocytes (Spearman rank correlation). Results: Agnostic to metabolic disease, PWH had lower proportions of pre-adipocytes (median 20.4% in non-diabetic and 36.4% in diabetic) compared with HIV-negative diabetic participants (62.7%) (Figure 1). The proportion of CD8 T cells, monocytes and NK cells were significantly higher in PWH compared with HIV-negative participants, irrespective of metabolic disease. Pre-adipocyte and NK cells were inversely related in non-diabetic PWH (r = _0.68, p = 0.005), diabetic PWH (r = _0.70, p = 0.004) and HIV-negative diabetics (r = _0.51, p = 0.05). A similar trend was observed between CD8 T cells and pre-adipocytes. Conclusions: We have generated a detailed atlas of AT SVF by HIV and diabetes status and show that PWH have higher proportions of NK and T cells compared with diabetic HIV negative. We hypothesize that this may correlate with the HIV reservoir. Future studies will pair this data with measurements of the HIV reservoir quantification and ART drug levels to understand how AT contributes to viral persistence

Interleukin-17A is associated with flow-mediated dilation and interleukin-4 with carotid plaque in persons with HIV

Objective: Chronic inflammation contributes to the high burden of cardiovascular disease (CVD) in persons with HIV (PWH). HIV has broad effects on innate and adaptive immune cells, including innate lymphoid cells (ILCs) and CD4+ T-helper cells. At present, the relationship between CVD and plasma cytokines reflecting ILC/T-helper responses in PWH is not well defined. We investigated relationships between plasma cytokines and subclinical atherosclerosis. Design: A cross-sectional study. Methods: We recruited 70 PWH on a single antiretroviral regimen (efavirenz, teno- fovir, and emtricitabine) with at least 12 months of suppressed viremia and 30 HIVnegative controls. We quantified plasma cytokines and chemokines, including inter- feron-g, interleukin (IL)-4, IL-13, and IL-17A, markers of macrophage activation, and markers of endothelial activation using multiplex assays and ELISA. Cytokines were grouped using Ward's hierarchical clustering. Brachial artery flow-mediated dilation (FMD) and carotid plaque burden were determined using ultrasound. Multivariable linear regression and negative binomial regression analyses were used to assess the relationships of plasma biomarkers and endpoints adjusted for CVD risk factors. Results: We identified three distinct clusters in PWH, one containing Th1/Th2/ILC1/ ILC2 type cytokines, one with Th17/ILC3/macrophage-related cytokines, and a less specific third cluster. Lower FMD was associated with higher plasma IL-17A and macrophage inflammatory protein-1 a. In contrast, IL-4, a Th2/ILC2 type cytokine, was associated with carotid plaque. When HIV-negative controls were added to the models clustering was more diffuse, and these associations were attenuated or absent. Conclusion: Th17/ILC3 and Th2/ILC2-mediated immune mechanisms may have distinct roles in endothelial dysfunction and atherosclerotic plaque formation, respectively, in PWH