Fig. 5

Development of Tfh cells was similar in WT and Il21r KO mice with CIA. a Representative dot plots of CXCR5 and ICOS expression on CD4 T cells 14 days after CIA induction. Numbers (upper right quadrant) indicate the percentage of CXCR5⁺ICOS⁺ cells in CD4 T cells. b Absolute numbers of Tfh cells (CXCR5⁺ICOS⁺CD4⁺ cells) in the draining LNs of WT mice (filled circle) or Il21r KO mice (open circle) during the course of CIA. c Representative dot plots of CXCR5 and ICOS expression in CD154⁺ CD4 T cells 14 days after CIA induction. Numbers (upper right quadrant) indicate the percentage of CXCR5⁺ICOS⁺ cells in CD154⁺ CD4 T cells. d Absolute numbers of CII-specific Tfh cells (CXCR5⁺ICOS⁺CD154⁺CD4⁺ cells) in the draining LNs of WT mice (filled column) or Il21r KO mice (open column) during the course of CIA. Error bars represent mean ± SEM. Statistical significance was analyzed by two-way ANOVA with repeated measures (b, d). Data are representative of three independent experiments. CII type II collagen, Il21r KO IL-21 receptor knockout, PPD purified protein derivative, Tfh follicular helper T, WT wild type