Fig. 6. Production of PN IgA is independent of T_FR cells.

(A and C) Representative flow plot and (B and D) frequencies of T_FR and T_FH cells in (A and B) MLN and (C and D) PP from control (Bcl6^flox/flox) or T_reg-Bcl6^−/− (Foxp3^creBcl6^flox/flox) littermates 8 days after one PN + CT immunization. T_FR cells (FOXP3⁺) were gated on T_FH cells (CXCR5^hi PD1^hi). T_FH cells were gated on CD4⁺ CD44^hi live activated T cells (TCRβ⁺). (E and F) ELISA quantification of total IgA and PN IgA in stool of T_reg-Bcl6^+/+ or T_reg-Bcl6^−/− littermates 1 week after sixth immunization with PN + CT. Figures represent data from three independent experiments with three to six mice per group. Median of each group was compared with Mann-Whitney U test whereby (**) indicates significant differences with P <0.01. Error bars indicate SD