Fig. 3. Expression of OX40L by DC is required for effector Th1 responses.

To investigate the critical cellular interaction for generation of Th1 effector T cells, conditional OX40L-deficient mice targeting ILC3s (Rorc^cre) or DCs (CD11c^cre) were generated. a Expression of T-bet versus CXCR5 by 2W1S-specific CD44^hi CD4 T cells in Rorc^cre and Rorc^cre × OX40L^f/f mice. b Enumeration of CD44^hi 2W1S-specific CD4 T cells in Rorc^cre, Rorc^cre × OX40L^f/f and OX40^−/− control mice. c Enumeration of T-bet⁺ 2W1S-specific CD44^hi CD4 T cells in Rorc^cre, Rorc^cre × OX40L^f/f and OX40^−/− control mice. Data were pooled from 3 independent experiments (n = 11 Rorc^cre mice, n = 17 Rorc^cre × OX40L^f/f mice, n = 14 OX40^−/− mice). d Representative flow cytometric plots showing CD44^hi 2W1S-specific CD4 T cells in the spleen of CD11c^cre and CD11c^cre × H2-Ab1^f/f mice at 7 days post infection. e Enumeration of CD44^hi 2W1S-specific CD4 T cells. Data are representative of 2 independent experiments, n = 5 mice per group. f Expression of T-bet versus CXCR5 by 2W1S-specific CD44^hi CD4 T cells in CD11c^cre, CD11c^cre × OX40L^f/f and CD30^−/− × OX40^−/− mice. g Enumeration of 2W1S-specific CD44^hi CD4 T cells. h Enumeration of T-bet⁺ 2W1S-specific CD44^hi CD4 T cells. i Percentage of 2W1S-specific CD4 T cells expressing T-bet. j Enumeration of CXCR5⁺ 2W1S-specific CD44^hi CD4 T cells. Data were pooled from 3 independent experiments (n = 9 CD11c^cre mice, n = 10 CD11c^cre × OX40L^f/f mice, n = 15 CD30^−/− × OX40^−/− mice). Values on flow cytometric plots represent percentages; bars on scatter plots represents the median. Statistical significance was tested in e by using an unpaired, non-parametric, Mann–Whitney two-tailed T test and in b, c, h–j by using Kruskal–Wallis one-way ANOVA with post hoc Dunn’s test: *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001.