Conversion of Non-Immune Spleen Cells by Ribonucleic Acid of Lymphoid Cells from an Immunized Rabbit to Produce γM Antibody of Foreign Light Chain Allotype

Abstract

Abstract Spleen cells (SpC) from non-immunized rabbits were converted to antibody plaque-forming cells (PFC) by incubation with ribonucleic acid (RNA) extracts of peritoneal exudate cells (PEC) or lymph node cells (LNC) obtained from the immunized rabbits 5 days following one intravenous injection of 4 × 108 sheep red blood cells (SRBC). The RNA extract was inactivated by ribonuclease (RNase) but not by deoxyribonuclease (DNase) or trypsin, indicating that the conversion required intact RNA. Plaque formation was inhibited by 2-mercaptoethanol (2-ME) or goat anti-rabbit γM but not by goat anti-rabbit γG-Fc fragment indicating that the antibody produced by the PFC are of the γM immunoglobulin class. The conversion was specific for the SRBC antigen injected. By use of antibodies to the b4 and b5 allotypic specificities of immunoglobulin light chains, the allotypic specificity of the γM antibody produced by the PFC was identified by direct precipitation of the γM in the plaque or by inhibition of plaque formation. The γM antibody produced by converted SpC invariably possessed the allotypic specificity characteristic for immunoglobulins of the donor of the “immune” RNA extract and not of the donor of SpC. These results could not be explained by contamination of the RNA extracts with anti-SRBC, thus implying that a component of the RNA extract, presumably RNA itself, is providing a code for the synthesis of at least a part of the γM immunoglobulin molecule.