Lysates of turkey-grown Pasteurella multocida: protection against homologous and heterologous serotype challenge exposures.

Pastereulla multocida organisms were separated from the blood of experimentally infected turkeys by differential centrifugation. An average of 92% of the residual host-cell contamination was removed from the pasteurellas by density gradient centrifugation in sucrose. Sucrose suspensions of the turkey-grown pasteurellas partially lysed after freezing and thawing. Treatment of freeze-thawed suspensions with DNAse, hyaluronidase, lysozyme, EDTA, and Triton X-100 did not influence their ability to induce protection against homologous and heterologous serotype challenge exposures. Lysozyme, EDTA, and Triton X-100 completely lysed the pasteurellas and rendered the cross-protection factor(s) filterable. Addition of adjuvant to completely lysed P multocida did not appear to enhance protection in turkeys against heterologous serotype challenge exposure. Adjuvant added to the pellet or supernatant fraction of centrifuged complete lysate enhanced protection in turkeys. Vaccines prepared from different serotypes of turkey-grown P multocida protected chickens and mice against homologous and heterologous serotype challenge exposures.