Figure EV1. Spike binding and virus neutralization by single well supernatants.
Supernatants shown in (B) that exhibited a ratio of fluorescent signal on spike‐expressing cells to signal on non‐expressing cells > 1.2 (n = 326: 79 IgM, 141 IgG 106 IgA) were assayed for ability to neutralize SARS‐CoV‐2 pseudotyped VSV. Supernatants were serially diluted from 20–1,960 fold, and mixed with 100 pfu of VSV*ΔG‐SΔ21, which was then used to infect Vero cells. Assay was performed once for each supernatant in quadruplicate, and the titer defined as the maximum dilution at which virus proliferation was completely inhibited. For each supernatant tested, the GMFI as shown in (B) is shown on the vertical axis, and the neutralization titer is shown on the horizontal axis, slightly staggered by class, in order to minimize overlap of points. IgM, IgG, and IgA are plotted with black, blue, and red points respectively. P values at the top of the plot were calculated by chi‐square test of the null hypothesis that the likelihood that supernatants show a titer of 20 (the lowest dilution tested) or greater is equal among the three antibody classes.