Fig 4.

Complement-mediated bactericidal activity of chimeric anti-fHbp MAbs. (A to C) Survival of wild-type N. meningitidis group B strain H44/76 after 60 min of incubation with anti-fHbp chimeric MAbs and 20% human complement. Crosses with solid line, IgG1; open triangles with solid line, IgG2; open circles with dashed line, IgG3. (A) JAR 3; (B) JAR 5; (C) MAb502. (D) Geometric mean MAb concentrations (μg/ml) for 50% human complement-mediated bactericidal activity in three to four independent assays. Error bars represent two standard errors. For all three paratopes, bacteriolysis occurred at lower concentrations of IgG3 (hatched bars) than the respective IgG2 (gray bars) or IgG1 (white bars; P < 0.0001) subclasses. For JAR 3 and JAR 5, bacteriolysis occurred at lower concentrations of IgG1 than with the respective IgG2 subclass MAbs (P < 0.0001 and P = 0.01, respectively).