The Induction of Bacteriophage-Neutralizing Antibody by Mouse Spleen Immunogenic RNA

RNA extracted from the spleens of Swiss Webster mice immunized with bacteriophage 81a, which infects Streptococcus faecalis var. zymogenes, induced the formation of specific phage-neutralizing antibody when added to nonimmune mouse spleen fragments in culture. Antibody formation could be elicited by the addition of immunogenic RNA derived from one inbred mouse strain to nonimmune spleen fragments from other inbred mouse strains. The activity of immunogenic RNA was inhibited by treatment with RNase, but not by DNase, trypsin, amylase or moderate amounts of pronase. The active RNA sedimented in the lightest fraction of a 5% to 20% linear sucrose gradient, and was estimated to have an average sedimentation coefficient of 8.2 S by analytical ultracentrifugation.