Cloning, expression, and characterization of four soy allergens that cross react with bovine caseins

DOCENA GH,; CANDREVA ANGELA; CURCIARELLO R,; GONZALEZ V; BRUNO BLANCH L; PARISI G; FOSSATI, CA

Buenos Aires

Congreso; XXI World Allergy Congress; 2009

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> CLONING, EXPRESSION AND CHARACTERIZATION OF FOUR SOY ALLERGENS THAT CROSS REACT WITH BOVINE CASEINS   Docena G, Candreva A, Curciarello R, Gonzalez V, Bruno Blanch L, Parissi G, Fossati CA, Petruccelli S.   Cow´s milk (CM) allergy constitutes the main food allergy observed in the pediatric population in Argentina and in many other countries. Besides, soy-based formulas are the nutritional substitute mostly employed for treatment of CM allergy. However, adverse reactions have been reported in 40% of the treated patients. Our group has found that four soy allergens (A5A4B3, Gly m alpha-conglycinin, Gly m Bd 30K or p34 and Gly m Bd 28K or p28) cross-react with bovine caseins. These proteins were obtained as recombinant polypeptides and further used in different immunoenzymatic methods (immunoblotting, indirect and competitive ELISA). Employing polyclonal antisera and monoclonal antibodies specific to CM proteins, or serum from patients diagnosed as allergic to CM proteins, we demonstrated that these components specifically cross react with bovine casein proteins. Besides, a food allergy mouse model was used as an in vivo tool to confirm this cross reactivity. CM specific IgE and IgG1 antibodies recognized these soy proteins, splenocytes were in vitro activated with the recombinant proteins, while cutaneous tests were also positive with these recombinant proteins. Based on information obtained using different bioinformatics approaches we could model a common structure for these proteins, and then proposed three superficial epitopes that could be responsible for the observed reactivity. These peptides were synthetized on a solid phase, and were found to be reactive with goat and rabbit CM-specific antisera. In conclusion, we detected cross-reactivity between allergens of cow´s milk and soy, and three potential immunodominant epitopes that could be the target in an attempt to reduce the allergenicity of soy components. The results obtained maybe the basis to understand the intolerance that CM allergic patients experience when soy-based formulae are employed during the replacement treatment.