PROTECTION OF MICE FROM FATAL BUBONIC AND PNEUMONIC PLAGUE BY PASSIVE-IMMUNIZATION WITH MONOCLONAL-ANTIBODIES AGAINST THE F1 PROTEIN OF YERSINIA-PESTIS

Monoclonal antibodies (MAbs) to the fraction 1 (F1) protein of Yersini a pestis protected mice against fatal pneumonic as well as bubonic pla gue from wild-type F1+ organisms. The rare isolation of a virulent F1- isolate from surviving animals supports earlier studies suggesting th at improved vaccines should consist of immunogens to protect against F 1- variants. The high degree of protection with IgG MAb suggests that secretory IgA is not required for protection from pneumonic plague.