Figure 5. Cross-reactivity and cross protection induced by immunization of mice with PspA5-wP.

Western-blot analyses were carried out using total protein lysates from different pneumococcal strains and a 1∶500 dilution of sera from BALB/c mice immunized with PspA5 (A) or PspA5-wP (B). Mice were immunized through the nasal route with the different indicated vaccines. Three weeks after the last immunization mice were challenged with the 0603 pneumococcal strain (PspA1) through the nasal route and CFU were determined in nasal washes, 5 days after challenge. Circles represent individual pneumococcal loads and lines represent the mean for each mice group. Asterisks indicate significant differences when compared with indicated groups (*P = 0.01; **P = 0.003; ***P = 0.001, Mann-Whitney U test). Results were composed with two independent experiments.