FIG 4.

Protection from secondary pneumococcal disease following influenza virus infection by i.d. immunization with PspA and LT-IIb(T13I). Mice were immunized with 5.0 μg of PspA plus 1.0 μg of LT-IIb(T13I) (vaccinated) or with PBS (sham). Two weeks after the final booster immunization (day 34), mice were inoculated intranasally with biofilm-derived EF3030 pneumococci. Forty-eight hours after inoculation, mice received 40 PFU of IAV by the intranasal route. Tissues and nasal lavage samples were collected at 1 day (A) and 5 days (B) post-viral infection and measured for bacterial burden. Each dot represents an individual mouse (n = 10). Statistical analysis was performed using a Mann-Whitney test (ns, not significant; *, P < 0.05; ***, P < 0.001). Graphs include data from two independent experiments.