Synthesis of Normal and “Immunogenic RNA” in Peritoneal Macrophage Cells

Abstract

Summary RNA extracted from rat peritoneal macrophage cells following the phagocytosis of sheep red blood cells (SRBC) caused the synthesis of specific hemagglutinating antibody by normal rat spleen cells. The majority of the biological activity of the RNA was contained in the lightest of three distinct regions, the 6 to 10 S region identified by sucrose density ultracentrifugation. Pulse-labeling studies indicate that synthesis of RNA in the 6 to 10 S region is completed 30 min following the pulse in peritoneal cells during the phagocytosis of SRBC, and 60 min following the pulse in cells not exposed to antigen. Pulse-chase studies show that this RNA remains stable for at least 2 ½ hr following the pulse. Both the antibody response, and the synthesis of RNA in the 6 to 10 S region were inhibited by actinomycin D.