Ovalbumin-specific IgE modulates ovalbumin-specific T-cell response after repetitive oral antigen administration.
BACKGROUND
Some patients outgrow their food allergies even though their serum antigen-specific IgE levels remain high.


OBJECTIVE
To elucidate the role of T cells in outgrowing food allergies in the presence of antigen-specific IgE, we tracked antigen-specific T-cell responses after oral antigen administration.


METHODS
Ovalbumin (OVA)-specific T-cell receptor (TCR) and OVA-specific IgE transgenic (Tg) mice (OVA-TCR/IgE-Tg) and OVA-specific TCR Tg (OVA-TCR-Tg) mice were fed with high doses of OVA or PBS every other day. After 7 administrations, OVA-specific proliferation and cytokine production of mononuclear cells of the spleen, mesenteric lymph nodes, and Peyer's patches and the number of splenic CD4 + CD25 + T cells were analyzed.


RESULTS
Without OVA administration, the splenocytes from OVA-TCR/IgE-Tg mice exhibited a higher proliferative response and produced more IL-4 and IL-10 and less IFN-gamma than those from OVA-TCR-Tg mice. The proliferative responses of the splenocytes from either OVA-TCR/IgE-Tg mice or OVA-TCR-Tg mice fed with OVA were significantly reduced compared with those from PBS-fed mice. The number of OVA-specific TCR + T cells decreased in the spleen from OVA-fed mice, whereas the number of CD4 + CD25 + T cells increased. The suppressed proliferation of splenocytes of OVA-fed mice was partially resumed by neutralization of TGF-beta1, but not of IL-10.


CONCLUSIONS
The presence of OVA-specific IgE modulated the OVA-specific responses of the splenocytes. Irrespective of the presence of OVA-specific IgE, repetitive oral administration of OVA induced tolerance, which seems to be composed of clonal deletion/anergy and TGF-beta1-mediated active suppression.
Omata
Nemuko
N
Department of Pediatrics, Faculty of Medical Sciences, University of Fukui, 2303 Shimoaizuki, Matsuoka-cho, Yoshida-gun, Fukui 910-1193, USA.
Ohshima
Yusei
Y
Yasutomi
Motoko
M
Yamada
Akiko
A
Karasuyama
Hajime
H
Mayumi
Mitsufumi
M
D000284:Administration, Oral; D000818:Animals; D016207:Cytokines / Q000032:analysis / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D007108:Immune Tolerance; D007073:Immunoglobulin E / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000008:administration & dosage* / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D016207:Cytokines; D011948:Receptors, Antigen, T-Cell; D007073:Immunoglobulin E; D010047:Ovalbumin