Immunomodulatory Effect of Phosvitin Phosphopeptides on Forced Swimming-Induced Immune Dysfunction in BALB/c Mice

The dysfunction of the immune system can make the host susceptible to various diseases, and the consumption of immunomodulating agents can be an effective way to control immune responses. Phosphopeptides derived from egg yolk phosvitin exert various beneficial effects. This study investigated the immunomodulatory effect of egg yolk-derived phosvitin phosphopeptides (PPPs) on forced swimming-induced immune dysfunction in BALB/c mice. PPPs were prepared by high-temperature and mild-pressure (HTMP) pretreatment and enzyme hydrolysis combinations. PPPs, HTMP (HTMP pretreatment alone), and HTMP-TM (HTMP pretreatment-trypsin + thermolysin hydrolysis) (200 mg/kg body weight/d) were administered orally to mice for 14 days before the final forced swimming of 10.5 min. PPPs resulted in a significant decrease in splenic T- and B-lymphocyte proliferation in mice with immune alterations induced by high-intensity exercise. The administration of PPPs enhanced the natural killer (NK) cell cytotoxicity in forced swimming-induced mice. Also, PPPs exerted potent immunomodulatory effects by regulating the levels of cytokines (interferon IFN-γ, interleukin IL-2, IL-4, IL-6, and IL-10), serum immunoglobulins (IgA, IgE, and IgG), and nitric oxide (NO) in the splenocytes of BALB/c mice. These results suggest that PPPs have the potential to be developed as immunomodulatory components in the food and pharmaceutical industries.