Dietary nucleotides increase the proportion of a TCRγδ+ subset of intraepithelial lymphocytes (IEL) and IL-7 production by intestinal epithelial cells (IEC);: Implications for modification of cellular and molecular cross-talk between IEL and IEC by dietary nucleotides

We have investigated the effects of dietary nucleotides on intraepithelial lymphocytes (IEL) and intestinal epithelial cells (IEC) in weanling mice. The proportion of T-cell receptor (TCR) gamma delta(+) IEL in BALB/c mice fed a diet supplemented with nucleotides (NT(+) diet) was significantly higher than that in mice fed the nucleotide-free diet, while the proportion of TCR alpha beta(+) IEL in NT(+) diet-fed mice was significantly decreased. The change of the TCR alpha beta(+)/TCR gamma delta(+) ratio was mainly observed in a CD8 alpha alpha(+) subset of IEL. IEC from NT(+) diet-fed mice produced a higher level of IL-7, which is important in the development of TCR gamma delta(+) IEL, than those from control diet-fed mice. The expression levels of IL-7 and IL-2 receptors on IEL were not different between the two dietary groups. Our findings suggest that the increased population of a TCR gamma delta(+) IEL subset by feeding nucleotides may be caused by the increased production of IL-7 by IEC.