Abstract
Ribonucleic acid extracts obtained from lymph nodes of immunized rabbits homozygous for the b4or b5allele of light chain immunoglobulin allotypes were injected intravenously into nonimmunized rabbits homozygous for the alternate allele. Approximately 30 percent of the plaque-forming cells in the spleen yielded plaques with immunoglobulin M antibody possessing the allotype of the RNA donor. The allotype of the RNA donor was also found in the IgG immunoglobulin of lymphoid cell lysates as well as in the IgG isolated from the serum. These results suggest that the injected RNA has an informational role in the in vivo synthesis of immunoglobulins by host lymphoid cells.