FIG. 4.

Complement activation by native IgG and rEndoS-treated IgG. IgG was coated onto wells of microtiter plates. MBL-deficient serum from which C1q, factor D (D), and properdin (P) were removed was used as a complement source at a 1:4 dilution. Purified complement proteins were added to the serum as indicated on the left. C3 deposition was detected with enzyme-conjugated rabbit anti-C3c and was expressed relative to the amount of undiluted serum added. The means and standard errors of the means for two experiments with duplicate determinations are shown.