Fig. 5.

Lectin pathway activity expressed as percentage haemolysis of E-M-MBL in agammaglobulinemic human serum (AHS), AHS depleted of C4bp (RC4bp) and RC4bp reconstituted with purified C4bp (a); the dose response curve for C4bp restoration is shown in (b) and expressed as 50% lectin pathway haemolytic units (LH₅₀). Comparable experiments using serum depleted of factor H (RH) are shown in (c,d). Hemolytic activity was greatly enhanced in the absence of C4bp and, to an even greater extent, in the absence of factor H.