Figure 2.

The primary T cell response to sFliC is dependent upon CD103⁺cDC2 in the mucosa but not in the spleen. cDC populations in Irf4^fl/fl or Cd11c-cre.Irf4^fl/fl mice were evaluated in (A) MLN and (B) spleen. Irf4^fl/fl or Cd11c-cre.Irf4^fl/fl mice were either non-immunized (N.I.) or immunized with sFliC and T cell responses were evaluated 7 days later. Representative flow cytometry plots (percentages) and absolute numbers (graphs) of activated CD4⁺ T cells (CD3⁺CD4⁺CD44⁺CD62L⁻) in the (C) MLN and (D) spleen. Ex vivo sFliC-specific restimulations, single cell suspensions were restimulated with 5 μg/ml of sFliC in the presence of anti-CD40 (2 μg/ml), biotinylated anti-CD154 (5 μg/ml) for 48 h. Antigen-specific CD4⁺ T cells were identified by detection of the anti-CD154 by streptavidin. (E) MLN and (F) spleen representative flow cytometry plots (percentages) and absolute numbers (graphs) of CD154⁺ CD4⁺ T cells. Data shown as mean + s.d. (n = 4 mice/group) representative experiment of 3 performed. **P < 0.001; *P < 0.05, by two-way analysis of variance (ANOVA), N.S., not significant.