Polymorphic residues in HLA-B that mediate HIV control distinctly modulate peptide interactions with both TCR and KIR molecules.

Immunogenetic studies have shown that specific HLA-B residues (67, 70, 97, and 156) mediate the impact of HLA class I on HIV infection, but the molecular basis is not well understood. Here we evaluate the function of these residues within the protective HLA-B∗5701 allele. While mutation of Met67, Ser70, and Leu156 disrupt CD8+ T cell recognition, substitution of Val97 had no significant impact. Thermal denaturation of HLA-B∗5701-peptide complexes revealed that Met67 and Leu156 maintain HLA-peptide stability, while Ser70 and Leu156 facilitate T cell receptor (TCR) interactions. Analyses of existing structures and structural models suggested that Val97 mediates HLA-peptide binding to inhibitory KIR3DL1 molecules, which was confirmed by experimental assays. These data thereby demonstrate that the genetic basis by which host immunity impacts HIV outcomes occurs by modulating HLA-B-peptide stability and conformation for interaction with TCR and killer immunoglobulin receptor (KIR) molecules. Moreover, they indicate a key role for epitope specificity and HLA-KIR interactions to HIV control.

Pathways and Intersections: Multifaceted Approaches to Engage Individuals From Underrepresented and Marginalized Communities in HIV Research and Career Development.

BACKGROUND: The underrepresentation of historically marginalized groups in the HIV research workforce is a barrier to reaching national Ending the Epidemic goals. SETTING: The Harvard University Center for AIDS Research (HU CFAR) Diversity Equity and Inclusion Working Group (DEI WG) uses a multifaceted approach to enhance the field's diversity. METHODS: We established a DEI WG to improve the recruitment, inclusion, and retention of underrepresented minorities (URMs) in HIV research. We use community-based, participatory processes to establish and expand education and outreach programs about HIV care and research to better connect the HU CFAR to communities affected by HIV. This article reports on the development of the WG in July 2022, progress in its first year, and future plans. RESULTS: We have built a network of >50 investigators across the university for monthly meetings; partnered with existing research pathway programs for high school, undergraduate, and graduate students, directly supporting 7 new trainees and linking CFAR investigators to additional mentorship opportunities; and created 2-year Scholar Awards for 5 URM investigators in HIV. Planned work includes needs assessments for early-stage investigators to understand factors contributing to inclusion and retention and new pathway and outreach programming being developed with community partner minority-serving institutions. CONCLUSIONS: The HU CFAR DEI WG strives to ensure that individuals from underrepresented, marginalized, and minoritized communities have an opportunity to contribute to HIV research and that research is informed by the needs of the communities affected by the epidemic. An intersectional approach should be incorporated into HIV research pathway initiatives.

Hypermethylation at the CXCR5 gene locus limits trafficking potential of CD8+ T cells into B-cell follicles during HIV-1 infection.

CD8+ T cells play an important role in HIV control. However, in human lymph nodes (LNs), only a small subset of CD8+ T cells express CXCR5, the chemokine receptor required for cell migration into B-cell follicles, which are major sanctuaries for HIV persistence in individuals on therapy. Here, we investigate the impact of HIV infection on follicular CD8+ T cell (fCD8) frequencies, trafficking patterns, and CXCR5 regulation. We show that, although HIV infection results in a marginal increase in fCD8s in LNs, the majority of HIV-specific CD8+ T cells are CXCR5- (non-fCD8s) (P < .003). Mechanistic investigations using Assay for Transposase-Accessible Chromatin using sequencing showed that non-fCD8s have closed chromatin at the CXCR5 transcriptional start site (TSS). DNA bisulfite sequencing identified DNA hypermethylation at the CXCR5 TSS as the most probable cause of closed chromatin. Transcriptional factor footprint analysis revealed enrichment of transforming growth factors (TGFs) at the TSS of fCD8s. In vitro stimulation of non-fCD8s with recombinant TGF-ß resulted in a significant increase in CXCR5 expression (fCD8s). Thus, this study identifies TGF-ß signaling as a viable strategy for increasing fCD8 frequencies in follicular areas of the LN where they are needed to eliminate HIV-infected cells, with implications for HIV cure strategies.