Oral administration of a casein phosphopeptide and phosphorylated dextrin preparation enhances intestinal IgA production and gene expression relating to the IgA production and calcium absorption in mice.

摘要

Mice (5-wk-old) were given a diet containing 25% ovalbumin (OVA, control diet), a mixture of 24.9% OVA and 0.1% casein phosphopeptide preparation (CPP-added diet) or a mixture of 24.9% OVA and 0.1% phosphorylated dextrin preparation (PD-added diet) as a protein source for 5 wk. Faecal and intestinal IgA levels and mRNA extracted from Peyer's patch cells, were analysed by ELISA and DNA microarray analysis, respectively. Faecal and intestinal OVA-specific IgA levels, as well as faecal total IgA level, were significantly elevated in mice that were given the CPP-added or PD-added diet for 5 wk, compared with those of control mice. The expression of genes relating to IgA production and Ca absorption was increased in mice given the CPP-added or PD-added diet compared that of control mice. Moreover, there was a strong positive correlation in the relative gene expression of proteins relating to IgA production (r = 0.966), and Ca absorption/metabolism (r = 0.716) between mice in the CPP- and PD-added diet groups. In particular, Igj, Pigr, Atp2a2 and S100g increased by >2-fold in mice in the CPP- and PD-added diet groups, compared with those of the control mice. It is concluded that CPP and PD stimulate intestinal IgA responses and Ca absorption by the same mechanism, and enhance Ca absorption via the transcellular pathway.