Abstract: Crude somatic and capsular antigens were prepared respectively from Pasteurella multocida P-1059 strain （serotype 3） and A-898 strain （capsular group A） by heat-extraction. The crude extracts（CE） were purified by ammonium sulfate precipitation or high-pressure liquid chromatography （HPLC, G 4000）. ELISA, SDS-PAGE and enzyme treatment were used to analyse the biological properties of the purified materials. The results were as follows：（1） Binding activity of the precipitate to antibody rose with the increase of ammonium sulfate concentration.（2） Four protein peaks of P-1059 and three peaks of A-898 were obtained by HPLC. Antigenic reac-tivity was detectable only in the first peak of the both strains. （3）Upon SDS-PAGE, peak 1 of P-1059 showed three protein bands, corresponding to molecular wei -ghts of 54300, 45900 and 38300. （4）Purified materials of P-1059 and A-898 were treated respectively by pronase E, proteinase K,neuramidinase and sodium periodate. After treated with sodium periodate, the two kinds of antigen were not reactive to their specific antisera.It suggested that the antigenic determinant may be relative to carbohydrate. （5）The result of cross inhibition by ELISA between the purified materials of P-1059 and A-898 indicated that the former contained trace ingredient of the latter.

Key words: Pasteurella multocida, Somatic antigen, Capsular antigen, Purification, Biochemical and immunological analysis