Fig. 3.

Nasal T_RM generated after exposure to live pneumococcus are sufficient to mediate protection from secondary challenge. Mice were exposed to live pneumococcus (0603) or not (PBS), 1 month later treated with FTY720 (+FTY) or left untreated, then challenged I.N. with 0603. Nasal washes and tissue harvest were performed 7 days post challenge. a CFU in nasal washes. b Frequency and (c) absolute number of IL-17A⁺CD4⁺ T cells in the nose after ex vivo stimulation with WCA for 24 h. d Concentration of IL-17A in supernatants from nasal cells after ex vivo stimulation with WCA for 7 days. a represents a pool of four experiments, n = 5–10 mice/group/experiment. b–d represent a pool of two experiments, n = 5 mice/group/experiment. Horizontal lines indicate the median value. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001