Objective: Detennination and classification of Pasteurella multocida isolates from poultry in Mazandaran province, study of cross¬protection and virulence among different protein types in mouse. Samples: Eighteen Pasteurella multocida isolates obtained from poultry during 10 years (1988-1998) from Mazandaran province. Procedure: Twenty five to thirty /lg of bacterial protein was electrophoresed in a discontinuous polyacrylamide gel electrophoresis system. The concentration of acrylamide in resolving and stacking gels were 12% and 4.5% respectively. Minimum lethal dose of each protein type was determined by IP injection of several bacterial dilutions to groups (n= 3) of Balb/c mice. To study the cross- protection, four groups of 10 mice were immunized with vaccinal strain. The immunized mice together with control groups were challenged with homologous and heterologous protein type isolates.
Results: The electrophoretic pattern of the isolates contained over 30 polypeptide bands ranging from 24 to 174 kda. The overall
. protein pattern of the isolates were similar. The main difference was in the position of a major protein band, which is known as protein H. The position of this band was presented in 38,36.5 and 34 kda. Based on this difference the isolates were classified as protein types I, II and III respectively. Immunization of mice with the vaccinal strain (protein type I) protected the animals against homologous challenge.
Conclusion: According to results of this study, preparation of a polyvalent vaccine containing different protein types are suggested to prevent fowl cholera in Mazandaran province. J. Fac. Vet. Med. Univ. Tehran. 58,3: 197-201, 2003.