FIG 3.

Induction of toxin-neutralizing antibodies in mice. (A) Systemic TcdA-specific and TcdB-specific nAbs from immunized mice assessed using an in vitro toxin neutralization assay. Vero cells were exposed to mouse sera preincubated with either TcdA or TcdB, and the average CPE across two wells was assessed under ×10 magnification. “Media” represents the effect of toxin in the absence of serum. The bars indicate the medians for the groups. (B) Representative images displaying immune serum neutralization of the cytopathic effect of toxin. ***, P ≤ 0.001.