Results of serum killing assays.

<p><b>A </b><i>B. pertussis</i> BP338 and its isogenic mutants, RFBP2152 (<i>brkA</i>::<i>gent</i>) and BP338Vag⁻ (<i>vag8</i>::pEG7-Vag8). Shown are means of percent survival ± SEM of a representative experiment done in triplicate, *, <i>P</i><0.04 vs. wild type strain. The comparison of BP338 and BP338Vag8⁻ was done 4 times independently, in triplicate; three of those experiments included RFBP2152. <b>B </b><i>B. pertussis</i> 18–323Sm^r and its isogenic mutant 18–323Sm^rVag8⁻ (<i>vag8</i>::pEG7-Vag8). Shown are means of percent survival ± SEM of a representative experiment done twice in triplicate. *, <i>P</i><0.004. Inset shows binding of C1inh (arrow) to wild type 18–323Sm^r but not to 18–323Sm^rVag8⁻.