Fig. 4. BCL6 targets TOX in human T_FH cells.

(A) ChIP-seq analysis of BCL6 (two replicates) or histone H3 acetylated at Lys²⁷ (H3K27ac), monomethylated at Lys⁴ (H3K4me1), or trimethylated at Lys⁴ (H3K4me3) with input controls at TOX in human GC-T_FH cells presented as reads per million per nucleotide (RPM/bp). Previously identified BCL6-positive bindings were marked. Fold changes of TOX expression in (B) T cells transduced with BCL6-expressing lentiviral vector compared to non-T_FH cells or T cells transduced with control vector and in (C) human non-T_FH, T_FH, or GC-T_FH cells, respectively. FACS analysis of (D) CD4⁺CD45RO⁻ T cells and CD4⁺CD45RO⁺ T cells from human lymph nodes (LNs). CXCR5^hiPD1^hi GC-T_FH, CXCR5^intPD1^intT_FH, and CXCR5⁻PD1⁻ non-T_FH cells (in CD4⁺CD45RO⁺ T cells) were gated for (E) FACS analysis, and percentages of TOX gMFI over CD4⁺CD45RO⁻ T cells are shown. (F) CXCR5^hiPD1^hi GC-T_FH cells that expressed different BCL6 amounts (lo, int., or hi) were individually gated. (G) FACS analysis and percentage of TOX gMFI in BCL6 lo, int., and hi populations from CD4⁺CD45RO⁺CXCR5^hiPD1^hi GC-T_FH cells over CD4⁺CD45RO⁻ T cells are shown. Data are representative of three independent experiments. Each symbol represents a human donor, and the bar represents the mean. *P < 0.05 and ***P < 0.01.