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 nucleotides on antigen-specific Th1 and Th2 responses and IgE responses.


METHODS
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. Cytokine production by spleen cells and macrophages obtained from these mice was measured in vitro. BALB/c mice, 3 weeks old, immunized intraperitoneally with OVA adsorbed onto alum, were fed the NT(-) diet or the NT(+) diet for 4 weeks. Serum levels of antigen-specific antibodies in the BALB/c mice were determined by ELISA.


RESULTS
The level of production of antigen-specific 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 secretion 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 compared with those fed the NT(-) diet.


CONCLUSIONS
These results show that dietary nucleotides up-regulate the antigen-specific Th1 immune response through the enhancement of IL-12 production and suppress the antigen-specific IgE response.
Nagafuchi
S
S
Department of Nutritional Research, Nutrition Science Institute, Meiji Milk Products Co. Ltd., Kanagawa, Japan. n-shinya@mx7.mesh.ne.jp
Hachimura
S
S
Totsuka
M
M
Takahashi
T
T
Goto
M
M
Yajima
T
T
Kuwata
T
T
Habu
S
S
Kaminogawa
S
S
D000276:Adjuvants, Immunologic; D000818:Animals; D000918:Antibody Specificity; D000941:Antigens / Q000276:immunology; D004032:Diet; D005260:Female; D007073:Immunoglobulin E / Q000276:immunology*; D007371:Interferon-gamma / Q000032:analysis; D018664:Interleukin-12 / Q000032:analysis; D015847:Interleukin-4 / Q000032:analysis; D017737:Macrophages, Peritoneal / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D009711:Nucleotides / Q000276:immunology*; D010047:Ovalbumin / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D013154:Spleen / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*
D000276:Adjuvants, Immunologic; D000941:Antigens; D009711:Nucleotides; D011948:Receptors, Antigen, T-Cell; D018664:Interleukin-12; D015847:Interleukin-4; D007073:Immunoglobulin E; D007371:Interferon-gamma; D010047:Ovalbumin