Modulation of cell-mediated cytotoxicity function after alteration of fatty acid composition in vitro.

Fatty acids incorporated into cytotoxic T lymphocytes (CTL) during in vitro stimulation can enhance or inhibit the subsequent expression of cell-mediated cytotoxicity, depending on the class of fatty acid. Unsaturated fatty acids enhance cytolysis, whereas saturated fatty acids inhibit it. The effects of fatty acids on cytolysis can be mediated in the absence of cell division, thus eliminating relative clonal amplification or contraction as a basis for the observed effects. Nevertheless, the net result of fatty acid alteration is an increase (unsaturated fatty acids) or decrease (saturated fatty acids) in the frequency, in the treated immune population, of CTL capable of lysing target cells. These observations are best explained by a model in which fatty acid incorporated into cell membrane phospholipids results in a direct recruitment into or out of the pool of CTL within the immune population capable of lysing target cells under the conditions employed to assay cytotoxicity.