title: Immuno-suppressive effect of human macrophages. II. Influence of macrophages on the kinetics of DNA, RNA and protein synthesis in PHA-stimulated lymphocytes.
abstract: Human macrophages obtained by culturing blood monocytes in vitro for 8 days release a soluble factor(s) inhibiting DNA synthesis and cell proliferation in PHA-stimulated lymphocytes. Synthesis of RNA and protein was strongly inhibited in PHA-stimulated lymphocytes sedimented on macrophages, as well as in lymphocytes separeted from the macrophages by a membrane, thus demomatrating that inhibition of RNA and protein synthesis was also mediated by a soluble factor(s). The kinetics of the factor-mediated inhibition showed that RNA synthesis was readily inhibited, whereas there was a delay in the inhibition of protein synthesis, thus indicating that the inhibition of protein synthesis and cell proliferation is a result of a blocking effect on the nucleic acid synthesis. The kinetics of DNA and protein synthesis in lymphocytes relieved from macrophage-mediated inhibition indicate a cytostatic effect.
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis*; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology*; D008567:Membranes, Artificial; D010835:Phytohemagglutinins / Q000494:pharmacology; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis*
chemical_list: D008567:Membranes, Artificial; D010835:Phytohemagglutinins; D012313:RNA; D004247:DNA