SUPPRESSIVE EFFECT OF 2-ACETYL-4-TETRAHYDROXYBUTYLIMIDAZOLE ON CONTACT HYPERSENSITIVITY IN THE SKH - HR HAIRLESS MOUSE

The compound 2-acetyl-4-tetrahydroxybutylimidazole (THI), a component of ammonia caramel, has been shown to cause lymphopenia and to impair several immune functions in rats and mice. In this study we show that THI effectively suppresses contact hypersensitivity dose responsively in the hairless mouse, whether administered topically or orally. The s uppression was shown to be prevented by topical administration of the histamine antagonist, cimetidine, and by the dipeptide, carnosine. Spl enocytes from THI-treated mice failed to elicit normal contact hyperse nsitivity when transferred to naive mice. This suggests that THI acts by modifying splenocyte function, perhaps via a histamine-like recepto r site(s).