Immunomodulatory effects of walnut (Juglans regia L.) oligopeptides on innate and adaptive immune responses in mice

This study aimed to investigate the immunomodulatory effects of walnut (Juglans regia L.) oligopeptides (WOPs). Female BALB/c mice were randomly assigned to control, whey protein control and three WOPs groups, given deionized water, 220 mg/kg BW whey protein, 110, 220 and 440 mg/kg BW WOPs daily through drinking water for 30 days, respectively. The immonomodulatory activity determination of WOPs involved innate and adaptive immunity, spleen T lymphocyte subpopulations, serum cytokine and immunoglobulin levels. Our results showed that WOPs could significantly improve humoral and cell-mediated immune responses, macrophage phagocytosis and natural killer cell activity. Moreover, increased T and Th cells percentages, cytokines secretion of interleukin (IL)-2, IL-10, IL-12 and granulocyte–macrophage colony stimulating factor, and production of immunoglobulin (Ig)A, IgG, IgM and intestinally secreted IgA also contributed to these improvements. All these above indicated that WOPs could be a promising immunomodulatory dietary supplement at dosages ranging from 110 to 440 mg/kg BW.