FIG. 6.

MAb inhibition of VCP binding to fixed C3b-C4b. (A) Schematic diagram summarizing the experimental design. As described in Materials and Methods, C3b-C4b was deposited by immune complex-mediated complement activation. Serial dilutions of medium from vaccinia virus-infected cells were incubated with MAbs and then added to the wells. (B) Since the reactivity of all of the MAbs within each of the two groups was similar, representative data are shown for MAbs 3B1 (solid line, nonblocking) and 3D1 (dashed line, blocking). (C) Summary data showing the reactivity of all the MAbs with serial dilutions of vaccinia virus-produced VCP, SCR 1, control, and recombinant Pichia-produced VCP. +, reactivity in ELISA; −, no reactivity in ELISA.