CD4 T cells activated by TSLP-DC coexpress BCL6 and GATA3. (A) FACS staining for BLC6, TBET, GATA3, and RORGT in naive CD4 T cells co-cultured with TSLP-DC for 4 d. (B) Tonsillar CD4 cells analyzed as in A. Gates were set using fluorescence minus one plus isotype, and percentage of cells in each quadrant are shown for one representative donor. (C) Quantification of BCL6, TBET, GATA3, and RORGT MFI in naive CD4 T cells and from data shown in A and B from three or five independent experiments. Empty squares, naive CD4 T cells; dots, TSLP-DC activated CD4; triangles, tonsillar CD4⁺ T cells. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001, unpaired Student’s t test. (D) CD4 T cells sorted as CXCR5^hiPD1^hi at day 4 of co-culture with TSLP-DC were analyzed for intracellular expression of IL-4, IL-21, GATA3, and BCL6. One representative experiment is shown, and quantification of % of GATA3⁺/BCL6⁺ cells is plotted for four independent experiments. Mean ± SEM is plotted. *, P < 0.05; **, P < 0.01, paired Student’s t test.