CONJUGATED LINOLEIC-ACID MODULATES TISSUE-LEVELS OF CHEMICAL MEDIATORS AND IMMUNOGLOBULINS IN RATS

The effects of conjugated linoleic acid (CLA) on the levels of chemica l mediators in peritoneal exudate cells, spleen and lung, and the conc entration of immunoglobulins in mesenteric lymph node and splenic lymp hocytes and in serum were examined in rats. After feeding diets contai ning either 0 (control), 0.5 or 1.0% CLA for 3 wk, there was a trend t oward a reduction in the release of leukotriene B-4 (LTB4) from the ex udate cells in response to the dietary CLA levels. However, CLA did no t appear to affect the release of histamine. A similar dose-response p attern also was observed in splenic LTB4, lung LTC4 and serum prostagl andin E-2 levels, and the differences in these indices between the con trol and 1.0% CLA groups were all statistically significant. The reduc tion by CLA of the proportions of n-6 polyunsaturated fatty acids in p eritoneal exudate cells and splenic lymphocyte total lipids seems to b e responsible at least in part for the reduced eicosanoid levels. Sple nic levels of immunoglobulin A (IgA), IgG, and IgM increased while tho se of IgE decreased significantly in animals fed the 1.0% CLA diet. Th is was reflected in the serum levels of immunoglobulins. The levels of IgA, IgC, and IgM in mesenteric lymph node lymphocytes increased in a dose-dependent manner, while IgE was reduced in those fed the higher CLA intake. However, no differences were seen in the proportion of T-l ymphocyte subsets of mesenteric lymph node. These results support the view that CLA mitigates the food-induced allergic reaction.