Fig. 4: The divergent differentiation of Tigit^– and Tigit⁺ PD-1⁺CXCR5⁺CD4⁺ T cells.

a, b Purified OT-II cells were transferred into CD45.1⁺ SMARTA recipient mice followed by intranasal infection with PR8-OVA. Indicated donor cell populations at day 28 p.i. in the medLN (a) or spleen (b) were analyzed for PD-1, CXCR5, Tigit, and IL-7Rα staining (n = 11). c–e CD45.1⁺CD45.2⁺ and CD45.1⁺ C57BL/6 mice were intranasally infected with PR8. CD45.1⁺CD45.2⁺CD44⁺Tigit⁺IL-7Rα^–PD-1⁺CXCR5⁺ (Tigit⁺IL-7Rα^–) and CD45.1⁺CD44⁺Tigit^–IL-7Rα⁺PD-1⁺CXCR5⁺ (Tigit^–IL-7Rα⁺) CD4⁺ T cells at day 14 p.i. were sorted and co-transferred into CD45.2⁺ C57BL/6 recipient mice followed by intranasal infection with PR8. c Ratio of the two donor cell populations (left panel) and Tigit and IL-7Rα expression on indicated donor cell populations (right panel) before transfer. d Ratio of the two donor cell populations (left panel) and quantification of relative percentages at day 14 p.i. (right panel, n = 8). e Donor CD4⁺ T cells at day 14 p.i. in the medLN were analyzed for PD-1 and CXCR5 staining, with quantification of indicated populations and PD-1^hiCXCR5^hi GC-Tfh to PD-1⁺CXCR5⁺ cell ratios (n = 8). Data in a–e are representative (or pooled) results of at least two independent experiments. Bars represent average ±SD. The P-values were determined by a two-tailed paired t-test (d, e), or a one-way ANOVA with Tukey’s multiple comparisons test (a, b). Source data are provided as a Source Data file.