Effect of fatty acid mixtures on phytohaemagglutinin-stimulated lymphocytes of different species.

It has been shown that changes in fatty acid turnover are an early event in the response in vitro of animal lymphocytes to mitogens (Resch & Ferber, 1972). Fatty acids added to the medium in ethanol inhibit the increase in uridine and thymidine uptake in human lymphocytes, which is a normal part of the response (Meriin ef al., 1974). We have previously reported that even when bound to albumin, single fatty acids still inhibit the blast transformation of human lymphocytes (Weyman et al., 1975), but that certain combinations of acids inhibit little or not at all, whereas with other combinations the inhibition is greater than with single acids. In the human, mixtures containing only saturated acids and those containing only unsaturated acids gave considerable inhibition, but mixtures in which a balance was maintained between saturated and unsaturated acids inhibited comparatively little. An exception was found to this rule, in that myristate did not itself inhibit, but relieved the inhibition by both saturated and unsaturated acids. We have now extended this work to examine the response of lymphocytes of several species to the inclusion of acids in the medium. The results are summarized in Table 1 (the results from the human are included for comparison).