title: Modulation in vitro of human natural cytotoxicity, lymphocyte proliferative response to mitogens and cytokine production by essential fatty acids.
abstract: Essential fatty acids (EFA) have been shown in animal studies to have a differential effect on various aspects of immune reactivity. However, there have been few studies in humans. Therefore, we elected to investigate the effects of a variety of EFA [gamma-linolenic acid (GLA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] in vitro on human blood lymphocyte reactivity, cytokine secretion and natural cytotoxicity. The proliferative response to polyclonal mitogens (phytohaemagglutinin, pokeweed mitogen, concanavalin A), as measured by [3H]thymidine incorporation into newly synthesized lymphocytes, was inhibited (P < 0.05) by all EFAs tested, in a dose-dependent manner (3-15 micrograms/ml). The greatest inhibition of proliferation was caused by EPA and DHA. Similarly, EPA, DHA and GLA significantly reduced cytotoxic activity [expressed as lytic units, using 51 chromium-release assays natural killer (NK) (K562 cells) and lymphokine-activated (LAK) (Daudi cells) cells] (P < 0.05) in a concentration-dependent manner (5-50 micrograms/ml), without affecting cell viability. EPA and DHA exhibited greater suppression than GLA. Furthermore, the inhibition of cell proliferation and suppression of natural cytotoxicity was associated with marked decrease in cytokine [interleukin-1 (IL-1), IL-2, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma)] production in vitro. Our findings demonstrate that EFAs (GLA, EPA, DHA) have the potential to inhibit significantly various aspects of human lymphocyte cell-mediated and humoral immune reactivities.
authors.affiliation: Department of Surgery, Medical School, University of Aberdeen, Foresterhill.
authors.forename: P
authors.initials: P
authors.lastname: Purasiri
authors.forename: A
authors.initials: A
authors.lastname: Mckechnie
authors.forename: S D
authors.initials: SD
authors.lastname: Heys
authors.forename: O
authors.initials: O
authors.lastname: Eremin
mesh_terms: D018929:Cell Culture Techniques; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis*; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D004306:Dose-Response Relationship, Immunologic; D005228:Fatty Acids, Essential / Q000494:pharmacology*; D005260:Female; D006801:Humans; D015979:Killer Cells, Lymphokine-Activated / Q000187:drug effects / Q000276:immunology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male
chemical_list: D016207:Cytokines; D005228:Fatty Acids, Essential