Neutralizing chimeric anti-F1 monoclonal antibody against Yersinia pestis infection.

Drug-resistant Yersinia pestis (Y. pestis) poses a threat to the use of antibiotics to treat Y. pestis infections. Passive immunization with neutralizing monoclonal antibodies (mAbs) is considered an effective approach for the treatment of infectious diseases. In this study, a murine single-chain fragment variable (scFv) phage antibody library targeting the F1 antigen was constructed and screened. Therapeutic intravenous injection of 400 μg chimeric mAb S1 through tail veins provided complete protection against Y. pestis 201 challenge in a pneumonic plague mouse model. Timely antibody treatment eliminated the bacteria and reduced lung inflammation. These data suggest that chimeric mAb S1 is a candidate treatment for Y. pestis infection that warrants further study.