title: Dietary fish oil decreases secretion of T helper (Th) 1-type cytokines by a direct effect on murine splenic T cells but enhances secretion of a Th2-type cytokine by an effect on accessory cells.
abstract: Dietary fish oil is considered to have anti-inflammatory effects based primarily on its effects on T-cell proliferation and IL-2 secretion. Its effects on the secretion of T helper (Th) 1-type cytokines vary and few studies have examined its effects on the secretion of Th2-type cytokines. In the present study, we examined the effects of dietary fish oil on the secretion of Th1 and Th2-type cytokines by splenocytes and the mechanism by which dietary fish oil affects Th2-type cytokine secretion. Mice were fed diets supplemented with 18 % fish oil (w/w) +2 % maize oil or 20 % maize oil for 6 weeks. Spleen cells, isolated splenic T cells and accessory cells (splenocytes depleted of T cells) were stimulated with anti-CD3/anti-CD28. The secretion of interferon (IFN)-gamma, TNF-alpha, IL-4 and IL-10 was measured by ELISA. Dietary fish oil decreased the secretion of IFN-gamma and TNF-alpha by total splenocytes and isolated T cells. In contrast, dietary fish oil increased the secretion of IL-4 by total splenocytes but had no effect on IL-4 secretion by isolated T cells. When isolated T cells were cultured with CD11b+ cells (mainly macrophages), cells from mice fed the fish oil diet secreted more IL-4 than cells from mice fed the maize oil diet. These results demonstrate that dietary fish oil directs cytokine secretion by splenocytes towards a Th2 phenotype and that the effects of dietary fish oil on the secretion of a Th2-type cytokine are mediated by its effect on CD11b+ accessory cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland.
authors.forename: Dagbjort H
authors.initials: DH
authors.lastname: Petursdottir
authors.forename: Ingibjorg
authors.initials: I
authors.lastname: Hardardottir
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D018122:B7-1 Antigen / Q000276:immunology; D051940:B7-2 Antigen / Q000276:immunology; D018106:CD28 Antigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000032:analysis / Q000378:metabolism*; D005227:Fatty Acids / Q000008:administration & dosage / Q000032:analysis; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage* / Q000737:chemistry; D005434:Flow Cytometry; D007371:Interferon-gamma / Q000032:analysis / Q000378:metabolism; D016753:Interleukin-10 / Q000032:analysis / Q000378:metabolism; D015847:Interleukin-4 / Q000032:analysis / Q000378:metabolism; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010938:Plant Oils / Q000008:administration & dosage; D011897:Random Allocation; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology*; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000378:metabolism; D003313:Zea mays
chemical_list: D000893:Anti-Inflammatory Agents; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; D017252:CD3 Complex; D016207:Cytokines; D005227:Fatty Acids; D005395:Fish Oils; D010938:Plant Oils; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma