Separation of soluble Brucella antigens by gel-filtration chromatography.

Soluble precipitating antigens of Brucella suis have been, in various degrees, purified by filtration on Sephadex gels. The most useful gels employed were Sephadex G-150, Sephadex G-200, and Sepharose 4B. Although not all fractions proved to be immunologically pure, some crude molecular-size estimates of most of the 13 soluble antigens of the Brucella cell could be given. In addition, monospecific antisera to three purified Brucella antigens have been prepared. By using purified preparations, physical and chemical data were obtained on two major antigens, E and 1, and a minor antigen, f. Antigen E is not an agglutinogen and may be toxic. Antigen 1 is of low molecular weight and is neither toxic nor agglutinogenic. The minor antigen f is an agglutinogen as well as a precipitinogen and is found on the cell surface. Both major antigens, when purified, were immunogenic in rabbits.