MODULATION OF RAT AND HUMAN LYMPHOCYTE FUNCTION BY N-6 AND N-3 POLYUNSATURATED FATTY-ACIDS AND ACETYLSALICYLIC-ACID

The effects of in vitro additions of between 10 and 100 muM n-6 and n- 3 polyunsaturated fatty acids were examined on the proliferation of st imulated T lymphocytes in culture. For both phytohemagglutinin-induced human blood lymphocytes and concanavalin-A-induced rat splenic lympho cytes, the largest inhibitory effects were obtained with 22:4 n-6 and 22:6 n-3, and to a lesser extent with 20:5 n-3. Arachidonic acid 20:4 n-6, the main eicosanoid presursor, was not inhibitory, it even stimul ated rat lymphocyte proliferation. Acetylsalicylic acid stimulated bot h human and rat lymphocyte proliferation. The effects of moderate decr eases in the dietary n-6/n-3 ratio by either linseed oil or fish oil m aximum eicosapentaenoic acid (MaxEPA) were determined on rat lymphocyt e proliferation and natural killer (NK) cell activity in vitro. Dietar y changes did not affect mitogen-induced lymphocyte proliferation in v itro, but proliferation of unstimulated lymphocytes was significantly lowered (4-fold) with the n-3-enriched diets. Dietary fish oil but not linseed oil significantly increased the NK cell activity of rat splen ic lymphocytes. The n-3-enriched diets, especially the fish oil diets, reduced the stimulatory effect of in vitro added acetylsalicylic acid (aspirin) on lymphocyte proliferation.