Induction of antibody synthesis in vitro by immunogenic RNA

Spleen cells (SpC) from nonimmunized CFW mice were converted into antibody plaque-forming cells (PFC) by incubation with RNA extracted from livers and spleens of immunized mice (4 days after a single intravenous injection of 0.2 ml of 5% sheep red blood cells (SRBC). RNA was extracted by the phenol-detergent procedure only when sensitization determined by the technique of Jerne showed at least one PFC per 1,500 SpC. Immunogenic activity of RNA from lives of immunized mice was identical with that of RNA from spleens. Immunogenic RNA was inactivated by RNase but not by DNase or pronase, indicating that induction of antibody synthesis requires intact RNA. Newly synthesized antibodies were specific for the SRBC injected antigen; plaques did not occur when other RBC were used in place of SRBC for the in vitro test. The influence of antibiotics on this phenomenon is also discussed.