Figure 5. CXCR5⁻PD-1⁺ICOS⁺ T Cells Are Clonally Related to T_FH Cells and Exhibit Epigenetic Similarities.

(A) Circos plots of TCR sequence overlap among different populations. Each thin slice of the arc represents a unique TCR sequence, ordered by the clone size (darker green for larger clones, inner circle). Outer circle indicate TCR sequences found in naive, CXCR5⁻PD-1⁻ICOS⁻, CXCR5⁻PD-1⁺ICOS⁺, and T_FH cells. Each plot represents data from one individual.

(B) Bhattacharyya coefficient measurement for the TCR repertoire similarity between CXCR5⁻PD-1⁺ICOS⁺ T cells and other populations within LN. Grey lines connect samples from the same patient (n = 9).

(C) Principal-component analysis of ATAC-seq data of LN CD4⁺ T cell subsets from 6 HIV⁺ donors. Each symbol represents cells from one donor; cells of the same type are coded by the same color.

(D) Representative chromatin accessibility at the CXCR5 upstream region for each CD4⁺ T cell subset.

(E) Example plots showing TCF1 and CD38 staining.

(F) Quantification of activated TCF1⁻ T cells among CXCR5⁻PD-1⁺ICOS⁺ T cells and T_FH cells in HIV⁺ LNs (n = 8).

(G) Sorted T_FH cells were labeled with carboxyfluorescein succinimidyl ester (CFSE) and treated with SEB or DMSO for 7 days in the presence of B cells. Bar graph quantifies the fluorescence intensity of CXCR5 staining on T_FH cells. Cell division was measured by dilution of CFSE staining (n = 6).

For (B) and (G), Friedman test was performed and corrected using Dunn’s multiple comparisons test. For (F), paired t test was used. Data are represented as mean ± SEM.

Also see Figures S5A, S5B, S4E, and S4F.