Fig. 5.

Effect of haemolysin on lectin pathway haemolytic activity in serum depleted of C4 bp and/or H. E-M-MBL and EA-M-MBL were incubated (37°C, 60 min) in unmodified agammaglobulinemic serum (AHS), AHS immunodepleted of C4 bp (RC4 bp), AHS depleted of factor H (RH) and AHS depleted of both C4 bp and factor H, and the LH₅₀ was determined in the usual way. The enhancement of mannan-binding lectin-mediated haemolysis by antibody persisted in C4 bp-depleted serum, while enhancement was no longer seen in serum depleted factor H or of both factor H and C4 bp.