ABSTRACT
In an attempts to produce a potent and protective vaccine against Corynebacterium pseudotuberculosis infections, immunogenicity of inactivated Cory. pseudotuberculosis cells, toxoid as well as BCG vaccine was investigated. The protection efficacy of toxoid alone was exceeding that produced by the different combinations comprises; toxoid and BCG fractions as well as toxoid with killed cells and BCG fractions, respectively. Partially purified exotoxins; phosholipase D [PLD]; with 128 and 256 toxic potancies produced by different toxigenic isolates were used for toxoid preparations. The potancies of different toxin batches were determined by using sheep erythrocytes detection system. In conclusion, toxoid is a major factor in inducing protection against Cory. Pseudotuberculosis infections. Moreover, the protection inducd by toxoid was not improved by incorporation of killed cells or BCG