Identification of protective cell surface proteins in ribosomal fractions from Salmonella typhimurium

Cell surface antigen preparations from Salmonella typhimurium SR-11 prepared by either trichloroacetic acid extraction or boiling in sodium dodecyl sulfate were able to protect C3H/HeJ, C3H/HeDub, and A/J mice. Some of the proteins found in these preparations were shown to exist in the protective ribosomal fraction isolated from S. typhimurium SR-11. Passage of ribosomes isolated from S. typhimurium SR-11 and 6707 through a Sepharose 2B column removed the protective immunogen from 6707 ribosomes but did not completely remove it from SR-11 ribosomes. Immunity to salmonella infection in C3H/HeJ mice induced by ribosomal vaccines may be dependent on the presence of cell surface proteins in the ribosomal fraction.