Cross-protection against fatal infections with pneumococcal strains expressing family 1 PspA.

<p>As in the prior studies the mother mice were immunized with a rPspA2 of strain TIGR4. Offspring at 10-days of age were intraperitoneally challenged with D39 (PspA1, serotype 2; 50 CFUs/mouse), BG7322 (PspA1, serotype 6B; 20 CFUs/mouse), EF3030 (PspA1, serotype 19F; 5×10⁶ CFUs/mouse), and L82016 (PspA1 serotype 6B, 5×10⁶ CFUs/mouse) in 100 µl with anesthesia. After challenge, the mice were monitored for 10 days to determine the day of death. Group A mice were offspring delivered from PspA-immunized mothers and breast-fed by the same mothers (n = 6 for D39, n = 10 for BG7322, n = 7 for EF3030, n = 6 for L82016). Group B mice were offspring from sham-immunized mothers and breast-fed by a PspA-immunized mothers (n = 7 for D39, n = 11 for BG7322, n = 4 for EF3030, n = 10 for L82016). Group C were offspring from PspA-immunized mothers and breast-fed by sham-immunized mothers (n = 9 for D39, n = 11 for BG7322, n = 5 for EF3030, n = 11 for L82016). Group D mice were offspring from sham-immunized mothers and breast-fed by the same mothers (n = 9 for D39, n = 5 for BG7322, n = 6 for EF3030, n = 6 for L82016). <i>p</i><0.05 and <i>p</i><0.01 for the indicated comparisons with offspring in Group D by Kruskal-Wallis test with Dunn's multiple comparison test are shown.