FIG 2 .

Human fH inhibits C3 deposition by adult nonhuman complement on PorB2-expressing quadruple mutants. Quadruple mutants of 7 strains of N. meningitidis were incubated with adult rabbit complement (A) or adult mouse serum (B) in either the absence (“−”; solid black bars) or the presence (“+”; gray bars) of human fH (80 µg/ml), and levels of C3 fragments deposited on bacteria were measured by FACS analysis. The control (open bar) represents C3 deposition when bacteria were incubated with heat-inactivated complement. The percentage of positive events relative to controls (bacteria plus heat-inactivated complement) is shown on the y axis. Each bar represents the SEM of the results of 2 to 3 independent observations. **, P < 0.01; ***, P < 0.001 (1-way ANOVA).