FIG 5.

Reverse cumulative distribution plot of the neutralization of LukAB-mediated PMN-HL60 cytotoxicity in the presence of sera from infected subjects or healthy controls. Convalescent-phase sera were significantly more potent than acute-phase sera (P < 0.01, paired t test) or healthy control sera (P < 0.001, independent t test) as measured by geometric mean neutralization titer. Samples were tested in duplicate, independently on separate days, and a third run was performed if the first two titer values differed by one dilution.