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

Abstract

CD8+ T-cells play an important role in HIV control. However, in human lymph nodes (LNs), only a small subset of CD8+ T-cells expresses 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-cells (fCD8s) frequencies, trafficking pattern and CXCR5 regulation. We show that, although HIV infection results in a marginal increase of fCD8s in LN, the majority of HIV-specific CD8+ T-cells are CXCR5 negative (non-fCD8s) (p<0.003). Mechanistic investigations using ATAC-seq 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 footprints analysis revealed enrichment of transforming growth factors (TGFs) at the TSS of fCD8s. In-vitro stimulation of non-fCD8s with recombinant TGF-β resulted in significant increase in CXCR5 expression (fCD8s). Thus, this study identifies TGF-β signaling as a viable strategy for increasing fCD8s frequencies in follicular areas of the LN where they are needed to eliminate HIV infected cells, with implications for HIV cure strategies.

CD8 lymphocytes mitigate HIV-1 persistence in lymph node follicular helper T cells during hyperacute-treated infection

“…5g ). These data are consistent with our recent publication where we showed by IF imaging that CD8 + T cells are largely excluded from GCs 44 . These data partly explain the observed greater HIV antigen burden in GCs relative to extrafollicular areas in some donors.…”

Partial compartmentalisation of HIV-1 subtype C between lymph nodes, peripheral blood mononuclear cells and plasma

“…Lymph nodes (LN), peripheral blood mononuclear cells (PBMC), and plasma (PL) samples were collected from individuals infected with HIV-1 subtype C from three cohorts in Durban, South Africa: the HIV Pathogenesis Programme acute infection cohort ( Radebe et al, 2011 ), the “Females Rising through Education, Support and Health” (FRESH) cohort ( Ndhlovu et al, 2015 ) and the Lymph Node cohort ( Ogunshola et al, 2022 ). Study participants were chosen based on the availability of LN samples and the availability of PBMC and PL samples that were collected close to the LN excision time point.…”

Role of CXCR5+ CD8+ T cells in human immunodeficiency virus-1 infection

“… Strategies for targeting CXCR5 + CD8 + T cells in immunotherapies against HIV infection. (A) Adoptive transfer of ex vivo expanded endogenous CXCR5 + CD8 + T cells with anti-PD-1 or anti-PD-L1 blocking antibodies or CXCR5 + CD8 + T cell-promoting cytokines, e.g., IL-15 super agonist ( Miller et al, 2022 ), recombinant IL-2 ( Codarri Deak et al, 2022 ; Perdomo-Celis et al, 2022 ), GSK3 inhibitor ( Perdomo-Celis et al, 2022 ), recombinant TGF- ß ( Ogunshola et al, 2022 ), overexpressed CXCR5 ( Ayala et al, 2017 ) and TCF1 ( Rutishauser et al, 2021 ) and using the CXCR5 expressed CAR-T ( Pampusch et al, 2022 ). (B) ART with anti-PD-1 or anti-PDL1 blocking antibodies combined with CXCR5 + CD8 + T cell-promoting cytokines, e.g., IL-15 super agonist ( Miller et al, 2022 ) and IL-2 ( Codarri Deak et al, 2022 ; Perdomo-Celis et al, 2022 ) in vivo .…”

“…A recent study found that CXCR5 – CD8 + T cells have closed chromatin at the cxcr5 transcriptional start site, in vitro culture with recombinant TGF-ß significantly increased CXCR5 expression. However, the detailed mechanism is still unknown ( Ogunshola et al, 2022 ). Thus, Id2, E2A, Tcf1, Bcl6, and Blimp1 form a transcriptional loop to regulate the CXCR5 expression and T FC cell generation in mice.…”