Inhibition of delayed hypersensitivity reactions by a new agent, cis-1-methyl-4-isohexylcyclohexane carboxylic acid (IG-10)—II. The mechanism regarding the action on lymphokines

A newly synthesized anti-allergic agent, cis-1-methyl-4-isohexylcyclohexane carboxylic acid (IG-10), has the capacity to inhibit the effector phase of delayed hypersensitivity reactions. In the present paper, the effect of IG-10 was studied on the generation of superoxide anion (O2) from macrophages, on macrophage chemotaxis, and on the activity of lymphokines such as skin reactive factor (SRF), macrophage migration inhibitory factor (MIF) and monocyte/macrophage chemotactic factor (MCF) in guinea pigs. Oral administration of IG-10 (50-200 mg/kg) inhibited SRF-induced skin erythema in a dose-dependent manner. In vitro, this agent (10(-7) -10(-5) g/ml) did not inhibit the generation of O2- from macrophages. The agent (10(-7) -10(-6) g/ml) significantly inhibited the activity of MIF and this inhibition was not due to the facilitation of normal migration. For macrophage chemotaxis, IG-10 (10(-8) -10(-6) g/ml) significantly inhibited MCF-induced chemotaxis. The agent also depressed the macrophage chemotaxis induced by N-formyl-methionyl-leucyl-phenylalanine but not the chemotaxis induced by E. coli culture filtrate. The inhibitory action of IG-10 on MCF activity was not influenced by antiglucocorticoid agents such as 17 alpha-methyltestosterone and androstenedione which reverse significantly the inhibitory action of glucocorticoids. The inhibitory action of IG-10 was relatively dependent on exogenous Ca2+ and Mg2+, and was antagonized by dbc-GMP.