Abstract/Summary

Lymphocytes play an important part in the development and progression of a number of autoimmune and inflammatory disorders, which are characterized by the presence of acti- vated T cells and cytokines at the site of tissue injury and in the circulation. There has been considerable interest in using dietary polyunsaturated fatty acids (PUFA), particularly the n-3 PUFA found in fish oils, in the therapy of these conditions; such therapies aim, primar- ily, to suppress T-lymphocyte activity. While several studies have investigated the effects of fatty acids on the production of monocyte- and macrophage-derived cytokines, few have investigated their effects on the production of T cell-derived cytokines. Each of these studies have been restricted to IL-2 and have produced results which are not entirely clear. Moreover, there have been no studies to investigate the effects of dietary lipids other than fish oils on IL-2 production or the effects of dietary lipids on lymphokines other than IL-2. To investigate the effects of dietary lipid manipulation on the production of IL-2, IL-4, IL-10 and IFN-γ by lymphocytes, mice were fed for 8 weeks on a low fat (LF) diet or one of 4 high fat diets, which contained 20% (by weight) hydrogenated coconut oil (HCO), olive oil (OO), safflower oil (SO) or menhaden oil (MO). Culture medium of lymphocytes from mice fed the OO or SO diets contained significantly more IL-2 than that of lymphocytes from mice fed the LF or HCO diets. Although this was the only statistically significant difference, there was a trend towards a lower concentration of IL-10 in the culture medium of lymphocytes from mice fed the unsaturated diets (OO, SO and MO) compared with those fed the LF or HCO diets. Whether this represents increased production of IL-2 and decreased production of IL-10 or decreased utilization of IL-2 and increased utilization of IL-10 by lymphocytes from mice fed the unsaturated diets is uncertain and requires further characterization.