Fig. 4: PD-L1- and IL-4-expressing basophils promotes ex vivo CD4⁺ T cell differentiation into TFH cells.

a–g CD3/CD28-stimulated wild-type (WT) naïve CD4⁺ T cells cultured for three days without (–, gray) or with basophils from Mcpt8^CT/+ (WT) (blue), Mcpt8^CT/+Il4^fl/fl (red), Mcpt8^CT/+Il6^fl/fl (orange), or Mcpt8^CT/+Pdl1^fl/fl (green) mice. a Proportions (%) of TFH cells among CD4⁺ T cells (n = 17/31/12/12/15). Proportions (%) of IL-21- (b), IL-6- (c), IL-4- (d), and IL-13- (e) producing cells among TFH cells non-restimulated (n = 11/16/5/10/8). f (Top) Proportions (%) of TFH cells among CD4⁺ T cells (n = 10/9/20/9). Bottom RT-qPCR done for the indicated targets on resorted CD4⁺ T cells. Relative results are presented with the color scale indicated from 0% (blue, the least abundant) to 100% (red, the most abundant). g Ratio of Bcl6 on Bach2 mRNA (Top) (n = 10/5/17/8) and of Batf on Bach2 mRNA (Bottom) (n = 13/5/17/8) as described in (f). h Top Proportions (%) of TFH cells among CD4⁺ T cells cultured without basophils for three days either alone (–, gray) or with coated anti-PD-1 antibody (red) or soluble IL-4 (green) or both (blue) (n = 10/12/12/8). Bottom. Relative mRNA expression of the indicated targets as in (f). i Ratio of Bcl6 on Bach2 mRNA (Top) (n = 10/5/4/6) and of Batf on Bach2 mRNA (Bottom) (n = 13/5/4/6) on samples described in (h). b–e Results for PMA/Ionomycin restimulated cells are shown in Supplementary Fig. 7e–h. a–i Results are from at least three independent experiments and presented as individual values in bars representing the mean ± s.e.m. Statistical analyses were done by Kruskal–Wallis test followed by Dunn’s multiple comparisons tests (a) or by one way ANOVA followed by Tukey’s multiple comparisons tests (b–i) between the indicated groups. P values are shown above each bracket. NS not significant. A.U. arbitrary units. Source data are provided in the Source Data file.