Modified caspase-3 assay indicates correlation of caspase-3 activity with immunity of nonhuman primates to Yersinia pestis infection.

Defined candidate human vaccines for treating infection by Yersinia pestis, the agent of plague, have been developed. To facilitate evaluation of the vaccines' efficacy, the in vitro caspase-3 assay for cytotoxicity-neutralizing activity was modified and reevaluated. Immune serum-mediated caspase-3 neutralizing activity correlated with protection against infection in a nonhuman primate vaccine model of plague immunity.