Immunomodulatory effects of marine oligopeptide preparation from Chum Salmon (Oncorhynchus keta) in mice

To observe the immunomodulatory effects of marine oligopeptide preparation (MOP) from Chum Salmon (Oncorhynchus keta) by the method of enzymatic hydrolysis, female ICR mice (6–8 weeks old) were administered the MOP for four weeks with the dose of 0, 0.22, 0.45 and 1.35 g/kg/body weight. In comparison with the control group, the MOP could significantly enhance the capacity of lymphocyte proliferation induced by the mitogen concanavalin A, the number of plaque-forming cells, natural killer cell activity, the percentage of CD4+ T helper (Th) cells in spleen and the secretion of Th1 (IL-2, IFN-γ) and Th2 (IL-5, IL-6) type cell cytokines. Nevertheless, no significant differences in weight gain, lymphoid organ indices and phagocytosis capacity were observed in our study. These results suggest that MOP is a possible immune stimulant and may strengthen the immune response of its host.