DIETARY BUTTER PROTECTS AGAINST ULTRAVIOLET RADIATION-INDUCED SUPPRESSION OF CONTACT HYPERSENSITIVITY IN SKH-HR-1 HAIRLESS MICE

Dietary fats modulate a wide variety of T cell functions in mice and h umans. This study examined the effects of four different dietary fats, predominantly poly unsaturated sunflower oil, margarine, and predomin antly saturated butter, clarified butter, on the T cell-mediated, syst emic suppression of contact hypersensitivity by ultraviolet radiation in the Skh:HR-1 hairless mouse. Diets containing either 200 g/kg or 50 g/kg butter or clarified butter as the sole fat source protected agai nst systemic photoimmunosuppression, whether the radiation Source was unfiltered ultraviolet B (280-320 nm) or filtered solar simulated ultr aviolet radiation (290-400 nm), in comparison with diets containing ei ther 200 or 50 g/kg margarine or sunflower oil. There was a linear rel ationship (r > 0.9) between protection against photoimmunosuppression and the proportion of clarified butter in mice fed a series of 200 g/k g mixed fat diets that provided varying proportions of clarified butte r and sunflower of. The dietary fats did not modulate the contact hype rsensitivity reaction in unirradiated animals. The observed phenomena were not primarily due to the carotene, tocopherol, cholecalciferol, r etinol, lipid hydroperoxide or the nonfat solid content of the dietary fats used and appeared to be a result of the different fatty acid com position of the fats.