Influence of dietary lipid on hapten-specific UV-induced immunosuppression

The influence of diets containing high (12%, w/w) and low (0.75%) levels of corn oil on hapten-specific antibody production to trinitrophenol-conjugated sheep red blood cells (TNP-SRBC) was examined in mice receiving 0, 3, 9, and 11 wk of UV radiation. Splenocytes from HRA HRII-c/+/Skh female hairless mice from the two dietary groups were incubated under a special atmosphere of low oxygen tension (7% O-2, 10% CO2, and 83% N-2) with TNP-SRBC to generate hapten-specific T-suppressor cells that, in turn, influence the number of direct plaque forming cells (PFC) in the Cunnigham-Szenberg plaque assay. Chronic UV irradiation reduced the number of direct PFC in both groups. After Il wk of UV, the number of PFC in the high dietary fat group was significantly lower (P<0.001) than that observed in the low fat group. These results suggest that dietary fat modulates UV-induced hapten-specific immunosuppression. Furthermore, the influence of dietary fat level, in this respect, was not realized until after II wk of UV, a time at which dietary fat has been shown to exert its influence on UV-carcinogenic expression.