Basophils and mast cells are crucial for reactions due to epicutaneous sensitization to ovalbumin

Abstract

Background

The prevalence of food allergies worldwide has increased recently. Epicutaneous sensitization to antigen could be a method to study food allergy

Methods

To clarify the mechanisms of food allergy, we established a mouse model of epicutaneous sensitization using ovalbumin. BALB/c mice were sensitized by three-time application of ovalbumin to tape-stripped skin (1-week sensitization at 2-week intervals) and oral challenge of ovalbumin undertaken. Rectal temperature was monitored. Blood and tissue (skin and jejunum) of challenged mice were taken. Numbers of mast cells (MCs) and basophils were counted. Serum and/or tissue levels of ovalbumin-specific IgE and IgG antibodies and several cytokines were measured using enzyme-linked immunoassay kits. MC- and basophil-depletion experiments were undertaken

Results

In ovalbumin-epicutaneous sensitized and orally challenged mice, systemic anaphylaxis (as evidenced by reduced rectal temperature) was observed. Levels of ovalbumin-specific IgE and IgG antibodies were increased in these mice, as were increased number of MCs and basophils. Serum levels of mast cell protease 1 were increased significantly. Basophil- and MC-depletion experiments revealed that they both participate in reactions. Increased production of thymic stromal lymphopoietin (TSLP) at skin sites of OVA-sensitization was noted

Conclusions

We speculate that TSLP produced from epidermal cells during antigen sensitization can enable basophils to promote a T-helper (Th)2 immune reaction, leading to and systemic anaphylaxis by antigen-specific IgE-bearing MCs. This TSLP–basophils–MC axis could be a novel therapeutic target against food allergy.

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