Turkish Journal of Veterinary & Animal Sciences




The immunogenicity of Pasteurella haemolyticaserotypes was investigated in an experimental animal model. Rabbits were immunized with bacterins and leukotoxins of selected serotypes of P. haemolytica,and the IgG level and antileukotoxin activities of immune sera were measured. The highest IgG levels against A1, A2, A7 and T4 antigens were detected in rabbits receiving polyvalent combined (bacterin plus leukotoxin) immunogens. Monovalent combined immunogens induced high antibody titers against homologous serotypes, but low titers against heterologous serotypes. Serotype A1 and A7 were found to be more antigenic than A2 and T4. The highest antileukotoxin activity in monovalent groups was detected in A1 and A7 antisera. Immune sera were used for the protection of mice challenged with homologous and heterologous serotypes. Antisera to polyvalent combined immunogens protected 83-100% of mice against A1, A7 and T4 challenge, and 50% of mice against A2 challenge. The lowest protection (16- 33%) was seen in serotype A6-infected mice, as heterologous challenge. In conclusion, marked differences were found in the immunogenicity of P. haemolytica serotypes and limited protection was observed against heterologous serotypes.


Pasteurella haemolytica, serotype, immunity, immunogenicity.

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