[Ribosomal dysentery vaccine. I. Method of production, physical and chemical properties]

Studies of A. and G. Youmans on the experimental tuberculosis led to discovery of a fundamentally new type of vaccines (ribosomal vaccines) which proved to be highly effective in the prophylaxis of many experimental infections. Therefore it seems reasonable to prepare analogous vaccine from Shigellae for the study of its efficiency in experimental shigellosis. Ribosomal preparations from Shigella sonnei were prepared by sonic disruption of microbial cells followed by differential ultracentrifugation according to A. and G. Youmans' method with slight modifications. The yeild of ribosomal fraction was about 2 per cent by weight; all the series had an UV adsorption maximum at 260 nm, the ratio OD260:OD280 being approximately 2. They contained about 55% of RNA, 35% of protein and no more than 8% of saccharides. As shown by centrifugation in sucrose gradient and by analytical ultracentrifugation the preparations were homogeneous. The presence of undissociated ribosomes was confirmed by electron microscopy. Thus, the ribosomal preparations obtained proved to be sufficiently purified for carrying out experimental investigations of their biological activity.