An improved Corynebacterium pseudotuberculosis vaccine for sheep.

Extensive experiments in mice confirmed that the immunogenicity of a Corynebacterium pseudotuberculosis vaccine could not be significantly improved with the use of various adjuvants. Immunity against C. pseudotuberculosis likewise could not be enhanced by incorporating various immunostimulants into the vaccine or by the use of live vaccines. However, a combination of aluminium hydroxide gel and saponin as adjuvant did have a beneficial effect. This vaccine was tolerated better, and a smaller dose apparently protected sheep more effectively against intralymph node challenge than the currently available alum-precipitated vaccine.