[Studies of the complement fixation reaction in infectious rhinotracheitis in cattle].

The complement-fixation reaction was used in the diagnosis of infectious bovine rhinotracheitis establishing its specificity and effectiveness. Highest titers of the antigens tested (up to 1:16) showed antigens that were concentrated with the use of poly ethylene glycol. In performing the test both the antigen and the complement were used in a dose that contained two units of each of them. Thus the use of the complement-fixation test proved instrumental in determining specific complement-fixing antibodies in animals that had recovered from the disease, or animals that had latent infection or had been vaccinated. The titers established usually ranged from 1:2 to 1:8, and in single cases they reached 1:128. On the infected farms some animals presented both complement-fixing and neutralizing antibodies. In Herds with positive reagents was also isolated the virus of bovine rhinotracheitis.