Fatty acid inhibition of lipopolysaccharide-stimulated B lymphocyte proliferation.

We have recently shown that saturated, monounsaturated and polyunsaturated fatty acids, including those of fish-oil origin, inhibit [ 'Hlthymidine incorporation into DNA of concanavalin A (Con A)-stimulated rat lymph node lymphocytes [ 1, 21. All nine fatty acids tested inhibited the response to mitogen, but the extent of inhibition was dependent upon the fatty acid concentration used, the time during culture of fatty acid addition and the duration of exposure of the cells to the fatty acid [2]. All fatty acids were inhibitory at concentrations of 50 p~ or above; at lower concentrations some were inhibitory and some were stirnulatory [ l , 21. Above SO p~ the inhibitory effect was concentration dependent [2]. Generally, unsaturated fatty acids were more inhibitory than saturated fatty acids; the greatest inhibition of proliferation was caused by 20:5, ti 3 and 20:4, n 6 and the least inhibition was caused by 14:O and 16:0 [ I , 21. These results confirm and extend a number of reports of the inhibitory effects of various fatty acids upon phytohaemagglutinin (PHA)stimulated lymphocyte proliferation (see [ 1-31 for references). Although all of these studies have been performed with cell populations containing a mixture of T and B lymphocytes the specificity of Con A and PHA as T-cell