Immunochemical characterization of Glycine max. L merr. var Raiden, as a possible hypoallergenic substitute for cow's milk allergic patients.

RENATA, CURCIARELLO; FABRICIO J, LAREU; CARLOS A. FOSSATI; GUILLERMO, DOCENA; SILVANA, PETRUCCELLI

CLINICAL AND EXPERIMENTAL ALLERGY

Blackwell Publishing ltd.

Año: 2008 vol. 38 p. 1559 - 1565

0954-7894

SummaryCows’ milk allergy (CMA) is the most common cause of food allergy in infancy.The only proven treatment is the complete elimination of cows’ milk proteins (CMPs) from thediet by means of hypoallergenic formulas. Soybean-based formulae are widely used althoughintolerance to soy has been reported to occur in 15–40% of infants with CMA.Objective The aim of this work was to analyse the in vitro reactivity of the soybean cultivarRaiden, which naturally lacks glycinin A4A5B3, to evaluate whether this genotype could be asafe CMP substitute for CMA patients.Methods The reactivity of conventional soybean (CS) and Raiden soybean (RS) genotypes andalso recombinant glycinin A4A5B3 and ab-conglycinin with casein-specific monoclonalantibodies and CMP-specific polyclonal serum was evaluated by immunoblotting and ELISA.A sequential competitive ELISA with the polyclonal antiserum and different soluble inhibitorswas performed. In addition, an indirect ELISA with sera of atopic children with CMA wascarried out to analyse the IgE-binding capacity of the different soybean components.ResultsWe have shown that CS contains four components that cross-react with CMP, while RShas only one. The remaining cross-reactive component in RS was identified as a-subunitb-conglycinin. By means of inhibitory ELISA, we demonstrated that CS, RS and the a-subunitb-conglycinin extracts inhibited the binding of CMP-specific antibodies to the CMP-coatedsolid phase. Finally, we showed that CS, RS and the recombinant proteins were recognized byhuman CMP-specific IgE antibodies.Conclusion This work shows that although Raiden has fewer cross-reactive components thanconventional soybean, it still has a residual cross-reactive component: the a-subunitb-conglycinin. This reactivity might make this genotype unsuitable to treat CMA andalso explains adverse reactions to soybean in CMA infants.