Cross-reactivity between the soybean protein P34 and bovine caseins"

CANDREVA, ANGELA MARIA; SMALDINI PAOLA LORENA; CURCIARELLO, RENATA; CAUERHFF, ANA; FOSSATI, CARLOS A; DOCENA, GUILLERMO H; PETRUCCELLI, SILVANA

Allergy, Asthma & Immunology Research

The korean academy of asthma, allergy and clinical immunology; the korean academy of pediatric allergy and respiratory disease

Año: 2015 vol. 7 p. 60 - 60

2092-7355

Background: Soy-based formulas are widely used as dairy substitute to treat milk allergic patients. However, reactions to soy have been reported in a small proportion of patients with IgE-mediated allergy to milk. The aim of this work was to analyze if P34 and P28 soybean allergens might be involved in this intolerance. Methods: In vitro recognition of P34 and P28 was evaluated by immunoblotting, competitive ELISA and BAT using sera from allergic patients. In vivo cross-reactivity was studied using a milk allergy mouse model. Results: P34 and P28 were both recognized by IgE antibodies of sera from milk allergic patients. In contrast P34 and P28 were differentially recognized by casein specific monoclonal antibodies and sera from milk allergic mice. Spleen cells from sensitized mice incubated with milk, soy or P34 secreted IL-5 and IL-13, while IFN-γ remained unchanged. In addition, in allergic animals the cutaneous tests was positive with P34 and negative with P28. Importantly, milk-sensitized mice developed immediate symptoms following sublingual exposure to P34. Conclusions: The results presented herein demonstrate that P34 shares epitopes with bovine casein, which are responsible for inducing hypersensitivity symptoms in milk allergic mice, thus showing the clinical relevance of this cross-reactivity. In contrast co-recognized epitopes in P28 were not involved in the allergic reactions in mice. This is the first report that demonstrates the in vivo cross-allergenicity of P34, which could set a new avenue for the development of a mucosal vaccine.