23] Preparation of Yersinia pestis plague murine toxin

Abstract

This chapter discusses the preparation of Yersinia pestis Plague Murine Toxin. Plague murine toxin appears to be an envelope protein component of the bacterium Yersinia pestis , formerly Pasteurella pestis . Isolated, the toxin may contain one or usually two related protein species of different molecular weights (120,000 and 240,000). The two proteins isolated are toxic for mice and rats at low levels. Mouse lethality then must be an important assay for ultimately determining the biological activity of the protein product. At the end of the growth cycle, toxin is released into the medium following autolysis of the cells. Immunodiffusion and gel electrophoresis assays also serve to facilitate routine assays of the toxin. Although both toxin A and B appeared routinely in the Y. pestis strain Tijwidej (TJW) preparations, toxin A seems to be the most biologically active of the two proteins. Also, a survey of different avirulent strains indicated it to be the most predominant if not the only toxin present in some Y. pestis extracts.