FIGURE 6.

Lack of a role for complement regulatory factors. A, no significant difference between binding of C4 binding protein to immobilized ES-62-, PChBSA-, or CWPS-coated microtiter plates. Plates were coated with ES-62, PCh-BSA, or CWPS as described previously and incubated with serum with (black bars) or without CRP (gray bars). Following incubation for 30 min with serum diluted in VBSCaMg or VBSMgEGTA buffer with or without CRP (0.4 μg/ml), the plates were washed, and C4bp was detected with biotinylated antiC4bp. Data are presented as mean ± S.E. of five different donor sera. B, factor H recruitment to the plate surface following CRP-mediated complement activation in response to PCh-BSA and CWPS but not ES-62. PCh ligand was coated to the plate to recruit equivalent CRP amounts, and following incubation with serum with or without added 0.4 μg/ml CRP at 37 °C for 30 min, the amount of factor H bound was determined. Two experiments on eight different donors were analyzed by paired t test.