FIG. 7.

C4 deposition. (A) C4 is composed of three chains, α, β and γ, connected by disulfide bonds (S—S). (B) Bacteria were incubated in 10% serum or heat-inactivated serum (HIS) for 15 min and were analyzed by Western blotting under reducing conditions with goat anti-human C4 antibodies. RFBP2171 (a), BP338 (b), and RFBP2152 (c) were tested. NHS, normal human sera. The three chains were determined by a comparison with bacterium-free serum that was run as a size control. (C) Densitometry was performed, and results are graphed as arbitrary units relative to RFBP2152 with standard error of three separate experiments. Densitometry results for RFBP2152 were significantly higher than for BP338 (P < 0.02) or for RFBP2171 (P < 0.03).