FIG. 2.

PspA⁺ and PspA⁻ pneumococci (closed and open circles, respectively) have equal virulence in C3⁻ and FB⁻ mice. Mice were infected intravenously with approximately 10⁷ CFU of PspA⁺ or PspA⁻ pneumococci and bled at various times thereafter to quantitate bacteremia. The data are presented as the means ± standard errors of the means for groups of two to five mice.