Allergic and anaphylactic response to sesame seeds in mice: identification of Ses i 3 and basic subunit of 11s globulins as allergens.

BACKGROUND: Allergy to sesame seeds is an emerging food allergy of a serious nature due to a high risk of systemic anaphylaxis. Although a mouse model to study sesame anaphylaxis is desirable, currently it is not available. Here, using a transdermal exposure model system, we tested the hypothesis that sesame seed elicits IL-4-associated IgE antibody response with consequent clinical sensitization in mice.
METHODS: Groups of BALB/c mice were exposed to sesame seed extract or saline or a control food (vanilla bean extract) by transdermal applications. Systemic IgE, IgG1 and IgG2a antibody responses were examined using preoptimized ELISA. Type 2 and type 1 cytokine responses were evaluated by ex vivo antigen-mediated activation of spleen cells. Clinical response to oral sesame challenge was studied. Western blot and N-terminal amino acid sequence analyses were performed to identify the sesame allergens.
RESULTS: Transdermal exposure to sesame elicited robust IgE and IgG1 but very little IgG2a antibody responses. IgE response to transdermal exposure in two high-IgE responder mice strains with disparate MHC confirmed the intrinsic allergenicity of sesame seed. Transdermal sensitization was associated with activation of IL-4 but not IFN-gamma. Furthermore, oral exposure to sesame resulted in clinical signs of systemic anaphylaxis. Western blot and sequence analysis identified four allergens including Ses i 3 and the basic subunit of 11s globulins.
CONCLUSION: These data argue that transdermal exposure to sesame seed can result in IL-4 activation, IgE response and clinical sensitization for systemic anaphylaxis.