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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Livestock Nutrient Management Research » Research » Publications at this Location » Publication #66004


item Purdy, Charles

Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Bovine respiratory disease causes an annual loss of $750 million to the feeder calf industry. Pasteurella multocida (Pm) is one of several bacterial agents responsible for bovine respiratory disease (BRD). The Pm bacteria are frequently found in the lungs of cattle dying of BRD however, their contribution in causing deaths is not understood. The neuraminidase enzyme has been implicated in several species of bacteria as a virulence factor which may contribute to the disease process. We have characterized the neuraminidases from the 16 major serotypes of Pm and determined that all 16 serotypes appear to be similar in molecular weight, substrate specificity and antigenic identity. We have demonstrated that Pm neuraminidases activity are neutralized by specific antibody. These results are important to researchers studying Pm neuraminidases concerning their potential as virulence factors in BRD.

Technical Abstract: Neuraminidases produced by 16 strains of Pasteurella multocida (serotypes 1 to 16) were characterized by molecular weight, substrate specificity and antigenic identity. After growth in a chemically defined medium, state I (lyophilized) culture supernatants were assayed for activity with N-acetylneuramin lactose, human a-1-acid glycoprotein, fetuin, colominic acid and bovine submaxillary mucin. Neuraminidase produced by P. multocid A:3 (PM A:3) was purified by a combination of salt fractionation, ion-exchange chromatography on DEAE-Sephacel, and gel filtration on Sephadex G-200. Purified PM A:3 neuraminidase was employed to immunize rabbits, and the resulting antiserum reduced the activity of the P. multocida A:3 enzyme by 40.3%. This antiserum also reduced the activity of the neuraminidases produced by the other serotypes by between 30.8 and 59.6%. Molecular weight estimates of the neuraminidases produced by the various serotypes were obtained by gel filtration chromatography on Sephadex G-200. All 16 serotypes examined produced a neuraminidase with a molecular weight of approximately 500,000. In addition, all 16 high molecular weight neuraminidases showed similar substrate specificities. On the basis of these data, it appears that the high-molecular weight neuraminidases produced by the different P. multocida serotypes are quite similar.