[Antigenic structure of the L forms of Br. Abortus 544]

The gel precipitation test after Ouchterlony and Mancini was employed to study comparatively the antigenic structures of S and L forms of Brucella abortus 544. Reduction of the antigenic fractions was established with the L-transformed Brucella organisms as compared to the initial cultures. Reduced were mainly fractions of the antigenic structures that took part in cell wall building. Cytoplasmic antigens remained unchanged. Those that participated in the building of cell walls precipitated in compact lines. On the other hand, the cytoplasmic antigens produced diffuse-and-compact precipitation zones. The intact antigenic structures retained their specificity.