Fig. 4.

CD4⁺ T_RM generated after mucosal immunization with WCV are sufficient to provide protection following nasal challenge with pneumococcus. Nasal washes and nasal tissue harvest were performed 4–7 days after challenge of mice immunized with CT or WCV and then left untreated, treated with FTY720, or anti-CD4 antibody (as indicated). a Levels of nasal colonization with pneumococcus. The results are representative of two experiments, n = 10 mice/group. b Absolute number of CD69⁺CD11a⁺CD4⁺ T_m cells in the nose. Frequency (c) and absolute number (d) of IL-17A⁺CD4⁺ T cells in the nose after ex vivo stimulation with WCA for 24 h. e Concentration of IL-17A in supernatants from nasal cells after ex vivo stimulation with WCA for 7 days. The results represent a pool of two experiments, n = 4–5 mice/group/experiment. Horizontal bars indicate the median value. *P ≤ 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001