Preliminary test of pseudovirus neutralization by mAb. Pseudovirus, Vietnam 1194, Turkey, Anhui, and VSV at 50x TCID50 were premixed with 10 μL mAb for 1 hour at 37°C before infecting MDCK cells in a total volume of 100 μL. Due to disparity in Ab yield from the ascites, protein contents in purified mAb vary significantly and antibody used in each assay is 109, 1, 174, 5, 318, 57, 283 μg for clone A, B, C, D, 3C4, 4H2, 6B8, respectively (left panel). The right panel is neutralization of pseudovirus infection by pepsin treated mAb. The amount of antibody used in each assay is equivalent to 3.7 μL of mAb, which are 40.3, 0.4, 64.4, 1.9, 117.7, 21.1, 104.7 μg for clone A, B, C, D, 3C4, 4H2, 6B8, respectively, see Method for detail. In both experiments, a control reference group that received no antibody was performed in parallel for each pseudovirus and its observation was considered 100%.