The immunoenhancing property of a dietary casein phosphopeptide preparation in mice

The effect on serum and intestinal IgG or IgA production of a dietary casei n phosphopeptide preparation, CPP-III, mainly consisting of residues 1-32 o f bovine alpha s2-casein and residues 1-28 of bovine beta-casein, was inves tigated in mice. No significant difference was seen in body weight gained b etween mice fed a CPP-III-added diet (a mixture of 0.1 to 1.0 g CPP-III and 24.9 to 24.0 g ovalbumin as protein sources in 100 g diet) and mice fed a control diet (25.0 g ovalbumin in 100 g diet). Mice fed CPP-III-added diets exhibited a similar serum IgG response towards beta-lactoglobulin injected peritoneally and ovalbumin ingested orally to those fed the control diet. In contrast, the level of serum IgA towards the proteins showed a rising te ndency in mice fed CPP-III-added diets compared with those fed the control diet. The difference between the control diet group and CPP-III-added diet groups was often statistically significant. Moreover, the intestinal antige n-specific IgA and total IgA in some mice fed the CPP-III-added diet were s ignificantly higher than those fed the control diet. The present results su ggest that oral use of the casein phosphopeptide is beneficial to the enhan cement of mucosal immunity.