Improvement of complement fixation test antigen for the diagnosis of Mycoplasma hyopneumoniae infection.

Several attempts were made to develop a complement fixation test antigen which is useful and practicable for the diagnosis of mycoplasmal pneumonia of swine. For the preparation of antigen, Mycoplasma hyopneumoniae was grown in broth medium containing horse serum for 14 days by shaking culture. Anticomplementary activity of antigen was eliminated by addition of complement and heating at 56 degrees C for 30 minutes. Storage of this antigen at 4 degrees C or at room temperature for 12 months had no significant effect on antigen titer. In the complement fixation test with this antigen, complement-fixing antibodies could be detected up to 41 weeks after experimental inoculation by KIO4 treatment of serum. They were demonstrated in 81.4% of 296 sera collected at slaughterhouses in five prefectures.