FIG 3.

ZMapp MAbs c2G4 and c4G7 competitively block entry of VLPs bearing EBOV GP. VLPs bearing EBOV-Mayinga GP (A) or EBOV-Makona GP (B) were incubated with the indicated concentrations of the indicated MAb for 1 h at 37°C. VLPs were then bound to and allowed to enter BSC-1 cells, and the extent of entry determined as described in Materials and Methods. The percent entry values were normalized to mock-treated (0 μg/ml MAb) controls. Data are the averages of triplicate samples, with error bars representing the standard deviations (SD) of the mean. Mock-treated VLP entry values were 35% for (a) and (b). Similar results were seen for three and two repeat experiments for panels A and B, respectively. (C) VLPs were treated with either 10 or 50 μg/ml c2G4, c4G7, or a combination of the indicated amounts of c2G4 and c4G7 and then processed as described above. Values are the percent inhibition of entry relative to mock-treated (no MAb) controls. Data are the averages of three experiments performed in triplicate, with error bars representing the SD. The percent entry values in mock-treated samples in the three experiments were 46, 41, and 36%. *, P < 0.05; **, P < 0.01; ***, P < 0.001 (A and B, relative to 0 μg/ml [no MAb] samples; C, relative to c2G4 alone).