title: Inhibition by adenine of in vitro immunological functions of normal and adenine phosphoribosyltransferase-deficient human lymphocytes.
abstract: Exogenous adenine strongly inhibited mitogen-stimulated transformation, cytoplasmic immunoglobulin production, and natural killer activity of human mononuclear leukocytes at the high concentration of 1.0 mM. These inhibitions by adenine were not due to cytotoxicity, because the viability of cultured cells was not affected by adenine up to 1.0 mM. As the magnitude of inhibition by adenine of these in vitro immunological functions was similar in normal and adenine phosphoribosyltransferase-deficient cells, its inhibition was not mediated by corresponding nucleotides. Adenine at the concentration of 0.1 mM caused 50% inhibition of cytoplasmic immunoglobulin production without alternating cell proliferation or viability. This suggests that an appropriate concentration of adenine may inhibit the differentiation of B cells to plasma cells rather than affecting cell proliferation. Understanding the mechanisms of adenine inhibition may lead to new approaches for the regulation of immune responses.
mesh_terms: D000225:Adenine / Q000494:pharmacology*; D000228:Adenine Phosphoribosyltransferase / Q000097:blood / Q000172:deficiency*; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects; D008214:Lymphocytes / Q000201:enzymology / Q000276:immunology*; D010430:Pentosyltransferases / Q000172:deficiency*
chemical_list: D010430:Pentosyltransferases; D000228:Adenine Phosphoribosyltransferase; D000225:Adenine