ميحرلا نمحرلا اللها مسب Molecular Characterization of Pasteurella multocida Vaccine Strains By:

The present study was carried out to study the national haemorrhagic septicaemia vaccine strains at their molecular level. The vaccine is bivalent contain Pasteurella multocida serotype E:2 and B:2. The vaccine strains were obtained from Central Veterinary Research Laboratory, Department of Biological Product, Soba. Culture characteristic and colonial morphology was ascertained in common laboratory media. The bacterial strains were characterized by using sodium-dodecyl sulphate polyacrylamide gel electrophoresis SDSPAGE, western blotting and by using PCR for capsular serotyping. Firstly, the two strains were characterized by SDS-PAGE technique. The bacteria were cultured in liquid media, and then the bacterial whole cell lysates were prepared. SDS-PAGE was carried out for both strains and the proteins bands were stained with coomassie brilliant blue. Then the molecular weights of the proteins bands were determined; they were 175 kDa, 165 kDa, 150 kDa, 123 kDa, 102kDa, 90 kDa, 85 kDa, 70 kDa, 64 kDa, 60 kDa, 51 kDa, 42 kDa, 37 kDa, 22 kDa and16 kDa. The protein profiles of both vaccine strains were similar. P. multocida strains protein profiles were investigated by immunoblotting using specific hyperimmune sera prepared in rabbits. Immunostaining with enzyme conjugate was done after transfer of proteins in nitrocellulose acetate paper. Eight proteins in whole cell lysate, of approximately 175 kDa, 102 kDa, 90 kDa, 85 kDa, 70 kDa, 42kDa, 37 kDa, and 16 kDa, were recognized by the sera.