The influence of dietary essential fatty acids on rat immunocompetent cell prostaglandin synthesis and mitogen-induced blastogenesis.

Sprague-Dawley rats were fed diets including 10% corn oil (CO), 10% hydrogenated coconut oil (HCO) or 10% linseed oil (LO), and immune cell populations isolated from peripheral blood and spleen were examined for alterations in prostaglandin E (PGE) synthesizing capacity and mitogen-induced blastogenesis. Culture conditions were optimized by incubating the cells in serum obtained from animals fed the same diet. The fatty acid profiles of these sera reflected the composition of the dietary fat ingested. Both the LO and HCO diet treatments resulted in significantly lower PG-synthesizing capacity by both unstimulated and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells or splenocytes when compared to the CO group. Mitogen-induced [3H]thymidine uptake by splenocytes from rats fed the HCO diet was twofold higher than responses observed in cells from animals fed the LO or CO diets. The results suggest that mitogenesis is not influenced by the diet-induced change in immune cell PGE2 synthesizing capacity. Enhanced [3H]thymidine incorporation was associated with a greater degree of saturation of dietary fat.