Correlations between IgM and CRP binding to the bacterial surface with complement C3 opsonization and serum survival. Correlations between surface binding of IgG (A and D), IgM (B and E), and CRP (C and F) with surface binding of C3 (A, B, and C) or survival in 10% pooled NHS (D, E, and F) for all blood and oropharyngeal NTHi isolates are shown. Linear regression was used to determine relationships between conditions.