Serum IgE response to orally ingested antigen: A novel IgE response model with allergen-specific T-cell receptor transgenic mice

Background: The mechanism by which orally ingested allergens elicit an IgE response remains unclear because there are few animal models available for investigation of this response. Objective: We tried to develop a murine model suitable for investigation of the IgE response to orally ingested allergens, which would allow us to ide ntify T cells that could promote IgE production. Methods: Ovalbumin (OVA)-specific T-cell receptor transgenic mice were fed a diet containing OVA, and both the serum antibody response and cytokine pr oduction by splenocytes were examined. Results: Oral administration of OVA to transgenic mice Led to an increase i n the levels of both antigen-specific IgE and total IgE in the sera. Subseq uent intravenous challenge of OVA-fed transgenic mice with OVA resulted in anaphylactic shock. Analysis of cytokine production by splenocytes revealed that high IL-4-producing T cells appeared in the spleen 1 week after the s tart of feeding the OVA diet. T cells from these mice were found to promote IgE secretion by BALB/c B cells in vitro. This helper activity and the lev els of IL-4 secretion were diminished after long-term feeding. These findin gs suggest the possibility that the orally ingested antigen elicited a resp onse by a subpopulation of T cells that produce high levels of T-H2-type cy tokines and that promote IgE secretion, and these same T cells were toleriz ed by the orally ingested antigen. Conclusion: This experimental model with transgenic mice may be a useful to ol for further studies of the cellular and molecular mechanisms of the T-ce ll and IgE responses to orally ingested antigens.