Use of a food allergy mouse model to study the in vivo and in vitro cross-reactivity between cow's milk and soybean proteins

SMALDINI P; CURCIARELLO R,; CANDREVA ANGELA; FOSSATI CA; PETRUCCELLI S,; DOCENA GH,

Congreso; First French-Argentine Immunology Congress. LVIII Reunión Anual de la Sociedad Argentina de Inmunología; 2010

Treatment of food allergy consists in allergen avoidance and food replacement. Cow´s milk (CM) is frequently substituted for soy (S)-containing formulae, however it is not tolerated in some patients even if they were not previously exposed to soy proteins. Our group has identified caseins and soy globulins as the cross-reactive allergens. They were obtained as recombinant proteins and cross-reactive epitopes were mapped.The aim of this work was to employ a validated food allergy mouse model to study the in vivo and in vitro cross-allergenicity between CM and S.BALB/c mice were intragastrically sensitized with CM proteins (CMP) and cholera toxin (CT) as a Th2 mucosal adyuvant. Control group consisted of mice exposed to CMP or CT. An oral challenge was performed with CMP or S, and 15-30 minutes afterwards clinical signs were recorded (clinical score). Cutaneous tests were performed, specific antibody (IgE, IgG1 and IgG2a) and histamine serum levels were quantified, antigen-specific proliferation of splenocytes was analyzed and cytokine production was measured. Sensitized animals showed higher clinical scores than control mice, and both CMP and S induced symptoms. Specific IgE and IgG1 antibodies were increased in sensitized mice, while IgG2a was suppressed. Histamine was increased and splenocytes were stimulated with CMP and S extracts. IL-5 (CMP: 132 ± 64 pg/ml vs. nd, S: 29± 11 vs 7±3 pg/ml, sensitized vs control group resp.) was also increased, while gIFN was basal (CMP: 80±16 vs. 26±13 pg/ml, S: 126±52 vs. 390±170 pg/ml sensitized vs control group resp.). Cutaneous tests were positive for CMP and soy. In conclusion, intragastric sensitization with CMP induced a specific Th2-bias activation of the gut mucosa immune system that also reacted with soy proteins. Cross-allergenicity was also evidenced by elicitation of clinical signs and cutaneous tests. These results may constitute the experimental basis to develop a mucosal vaccine