Development of an adjuvant-free cashew nut allergy mouse model.

BACKGROUND: Cashew nut allergy is an emerging food allergy with a high risk of systemic anaphylaxis. Currently, an adjuvant-free animal model to study cashew nut allergy is not available.

METHODS: BALB/c mice were exposed to cashew nut protein using a transdermal sensitization protocol that does not use adjuvant. Systemic IgE antibody response, systemic anaphylaxis to oral challenge and allergen-driven, spleen-cell, type-2 cytokine responses were studied.

RESULTS: Transdermal exposure to cashew nut resulted in a significant dose-dependent allergic response. Oral challenge of sensitized mice with cashew resulted in severe signs of systemic anaphylaxis and a significant hypothermia. Spleen cell culture with cashew nut protein resulted in allergen-driven IL-4, IL-5 and IL-13 responses only in sensitized but not in saline control mice.

CONCLUSIONS: These data demonstrate that (i) transdermal exposure to cashew nut protein elicits a robust IgE response leading to clinical sensitization of mice for systemic anaphylaxis to oral cashew nut challenge; (ii) cashew nut is a potent activator of type-2 cytokines, thus explaining the mechanism of cashew allergy, and (iii) this mouse model may be useful for further basic and preclinical studies on cashew nut allergy.