The use of gel diffusion precipitin plates in the study of Brucella.

The use of gel diffusion precipitin plates in the study of brucella is described.Cultures of Brucella melitensis yielded a diffusible precipitin antigen which produced lines with sera of rabbits, goats, and cattle that had been infected with either Br. abortus or Br. melitensis. The precipitin lines varied in number from one to three.A diffusible precipitin antigen could not be prepared from Br. abortus and Br. suis cultures by the methods which were effective in producing such an antigen from Br. melitensis.No precipitin reactions occurred with sera from cattle in brucella-free herds which had been inoculated with Strain 19 vaccine, although some of these sera were positive to the agglutination test.