Sutherland A D, Donachie W, Jones G E, Quirie M
Moredun Research Institute, Edinburgh, Gt. Britain.
Vet Microbiol. 1989 Feb;19(2):175-81. doi: 10.1016/0378-1135(89)90082-5.
Three vaccines containing Pasteurella haemolytica serotype A2 antigens were tested for their ability to protect sheep against a homologous challenge. A crude cytotoxin preparation in combination with a sodium salicylate extract (SSE) or crude cytotoxin alone were highly protective (98 and 86%, respectively), whereas SSE alone was poorly (47%) protective. These findings indicated that the crude cytotoxin was an essential component of a protective vaccine. Protection correlated with serum cytotoxin-neutralising (CN) titres and bactericidal activity, which were stimulated by antigens in the crude cytotoxin preparation.
