Dietary nucleotides can up-regulate antigen-specific Th1 immune responses and suppress antigen-specific IgE responses in mice

Background: It has been reported that dietary nucleotides enhance T helper cell activities, In this study, we have determined the effects of dietary n ucleotides on antigen-specific Th1 and Th2 responses and IgE responses. Met hods: Ovalbumin (OVA)-specific T cell receptor (TCR) transgenic (OVA-TCR Tg ) mice, 3 weeks old, were fed a nucleotide-free diet (NT(-) diet) or the NT (-) diet supplemented with dietary nucleotides (NT(+) diet) for 4 weeks, Cy tokine production by spleen cells and macrophages obtained from these mice was measured in vitro. BALB/c mice, 3 weeks old, immunized intraperitoneall y with OVA adsorbed onto alum, were fed the NT(-) diet or the NT(+) diet fo r 4 weeks. Serum levels of antigen-specific antibodies in the BALB/c mice w ere determined by ELISA. Results: The level of production of antigen-specif ic interferon-gamma by spleen cells was significantly higher in the OVA-TCR Tg mice fed the NT(+) diet than in the control mice. The levels of secreti on of bioactive IL-12 by spleen cells and peritoneal macrophages were also significantly increased in the NT(+) diet group, The serum OVA-specific IgE level was significantly decreased in BALB/c mice fed the NT(+) diet compar ed with those fed the NT(-) diet. Conclusion: These results show that dieta ry nucleotides up-regulate the antigen-specific Th1 immune response through the enhancement of IL-12 production and suppress the antigen-specific IgE response, Copyright (C) 2000 S. Karger AG. Basel.