FIGURE 4.

Bactericidal activity of nLc₄-nLc₃ IgG (top) and nLc₃ IgG (bottom) for the L3,7 N. meningitidis strain, 7946. y axis, percentage of cfu present at time 0 that survived after 60 min in the presence of increasing concentrations of each IgG added to a human serum (NHS) used as the complement source. The NHS added 2.7 μg of nLc₃ IgG and a negligible amount of nLc₄-nLc₃ IgG to each reaction. Error bars, S.D. values; *, p < 0.05 (t test; one tail) as compared with NHS. The nLc₄-nLc₃ IgG did not significantly reduce survival at any IgG concentration, whereas 50 μg/ml of the nLc₃ IgG reduced survival by ∼50%, and 100 μg/ml of this IgG reduced survival by ∼75%.