: It is not exactly known why certain food
proteins are more likely to sensitize. One of the characteristics of most food
allergens is that they are stable to the acidic and proteolytic conditions in the digestive tract. This property is thought to be a risk factor in allergic sensitization. The purpose of the present study was to investigate the contribution of the
protein structure of 2S
albumin (Ber e1), a major
allergen from Brazil nut, on the sensitizing capacity in vivo using an oral Brown Norway rat
food allergy model. Disulphide bridges of 2S
albumin were reduced and alkylated resulting in loss of
protein structure and an increased
pepsin digestibility in vitro. Both native 2S
albumin and reduced/alkylated 2S
albumin were administered by daily gavage dosing (0.1 and 1 mg) to Brown Norway rats for 42 days. Intraperitoneal administration was used as a positive control. Sera were analysed by ELISA and passive cutaneous anaphylaxis. Oral exposure to native or reduced/alkylated 2S
albumin resulted in specific
IgG1 and
IgG2a responses whereas only native 2S
albumin induced specific
IgE in this model, which was confirmed by passive cutaneous anaphylaxis. This study has shown that the disruption of the
protein structure of
Brazil nut 2S albumin decreased the sensitizing potential in a Brown Norway rat
food allergy model, whereas the immunogenicity of 2S
albumin remained preserved. This observation may open possibilities for developing
immunotherapy for Brazil nut
allergy.