Inhibition of delayed hypersensitivity reactions by a new agent, cis-1-methyl-4-isohexylcyclohexane carboxylic acid (IG-10).

A newly synthesized compound, cis-1-methyl-4-isohexylcyclohexane carboxylic acid (IG-10), has been reported as an inhibitor of delayed hypersensitivity reaction. In the present paper, the mechanisms regarding the inhibitory action of IG-10 was investigated on delayed hypersensitivity reactions. p-Phenylenediamine-induced contact dermatitis in guinea pigs was significantly inhibited when the drug was given in a dose of 100 mg/kg p.o. at various times after challenge with the antigen. IG-10 inhibited both contact dermatitis and monocytes or neutrophils infiltrations induced by picryl chloride in mice. A skin reaction, similar to that seen in the case of delayed hypersensitivity reaction, was induced by an intradermal injection of phytohemagglutinin-P (PHA-P) stimulated lymphocytes in guinea pigs. This reaction was a useful method for assessing the effect of drugs on the release of lymphokines, particularly skin reactive factor (SRF). IG-10 in a concentration of 10(-5) g/ml inhibited the release of SRF as well as the release of migration inhibitory factor (MIF) from guinea pig lymphocytes stimulated by PHA-P. The reduction of delta 4-3-ketone of aldosterone and/or hydrocortisone by rat liver homogenates was not affected with IG-10, unlike that seen in the case of glycyrrhizin.