Complement-mediated direct bacterial killing.

<p>10⁸ bacteria were incubated with the indicated serum concentrations in PBS⁺⁺ at 37°C. At the indicated times, samples were recovered and bacteria were enumerated by dilution plating (n = 4). * p<0.05 compared to respective <i>E. coli</i> values, as determined by one-way ANOVA; error bars represent standard error mean.