[Immunotropic activity of new hydroxypyrimidine derivatives]

The studies on immunotropic activity of the new hydroxypyrimidine derivative, 2,4,6-trimethyl-5-oxypyrimidine, have shown the compound to exert a predominant suppressant action on cell-mediated immune reactions without inhibiting antibody formation. After single intraperitoneal administration at doses within 50-500 mg/kg the drug produces a marked lymphotoxic action (27-46% of survived colony-forming cells), with the mitostatic effect being absent. No direct correlation between the drug dose and its action was recorded: an increase in the dose up to 500 mg/kg does not induce the effect potentiation. HPM-III inhibits hypersensitivity reaction of delayed type, depending on the administration regimen (prior to antigenous effect). Antiproliferative activity of the drug is little pronounced. At concentrations of 100, 250 and 500 mcg/ml of the lymphocyte culture, DNA incorporation of the labeled precursor is inhibited by 7, 13 and 35%, respectively. A slight decrease in the number of antibody-forming cells is noted only at secondary response. The synthesis of humoral antibodies is not inhibited.