FIG. 1.

PspA inhibits complement activation and clearance of pneumococci. XID mice were infected intravenously with approximately 10⁵ CFU of PspA⁺ or PspA⁻ pneumococci, and blood was collected to quantitate bacteremia (A) and serum C3 (B). The data are presented as the means ± standard errors of the means from a total of 15 mice per group (two experiments). Asterisks indicate significant decreases in bacteremia or serum C3 concentrations compared to 0-h (preinfection) values (P < 0.05, paired t test).