FIG 2.

In vitro and in vivo neutralization of toxins. (A and B) In vitro neutralization assay using Vero cells incubated with 100 pM TcdA or 0.6 pM TcdB per well for 24 h with serial dilutions of VNA2-Tcd as indicated. Percent cell rounding (cytotoxicity) was assessed after 24 h. The IC₅₀ was determined using the GraphPad nonlinear fit of log-transformed concentrations. Log IC₅₀ for TcdA = 2.0 and the IC₅₀ was 106.4; Log IC₅₀ for TcdB = 1.24 and the IC₅₀ was 13.3.