Abstract
Regulatory T cells (Tregs) play key roles in the immune response by preventing or suppressing the differentiation, proliferation and function of various immune cells. Recent studies report that the omega-3 polyunsaturated fatty acids (n-3 PUFAs) in fish oil can reduce inflammation in allergic patients. The beneficial effects of natural fish oil (NFO) have been described in many diseases, but the mechanism by which fermented fish oil (FFO) modulates the immune system and the allergic response is poorly understood. In this study, we produced FFO and tested its ability to suppress the allergic inflammatory response and to activate CD4+CD25+Foxp3+ Tregs. The ability of FFO and NFO to modulate the immune system was investigated using a mouse model of AD. Administration of FFO or NFO in the drinking water alleviated the allergic inflammation in the skin, and FFO was more effective than NFO. Neither FFO nor NFO increased forkhead box P3 (Foxp3) expression and/or affected the number of CD4+CD25+ T cells without any stimulation. However, FFO treatment did increase the expression of the immune-suppressive cytokines transforming growth factor-β (TGF-β) and Interferon-10 (IL-10). In addition, ingestion of FFO increased Foxp3 expression and the number of CD4+CD25+Foxp3+ Tregs in CD4+ T cells stimulated with anti-CD3 and anti-CD28 compared with NFO. These results suggest that the anti-allergic effect of FFO is associated with enrichment of CD4+CD25+Foxp3+ T cells at the inflamed sites and that FFO may be effective in treating the allergic symptoms of AD.
Key word : Atopic dermatitis AD, natural fish oil, fermented fish oil, transforming growth factor-β, forkhead box P3, regulatory T cells
