Mapping T epitopes in peptides from milk and soy to be used in a mucosal vaccine for food allergy

DOCENA, GUILLERMO; CURCIARELLO, RENATA; MUGLIA, CECILIA; CANDREVA, ÁNGELA; SMALDINI, PAOLA; CANZIANI, KARINA EVA

São Paulo

Otro; IUIS-Brazil Advanced Course of Vaccines; 2017

International Union of Immunological Societies

Cow?s milk allergy (CMA) is the most common cause offood allergy in infancy. Nowadays there is no standardized and approvedimmunointervention procedure. The only proven treatment is the complete eliminationof cows? milk proteins from the diet by means of hypoallergenic formulas.Soybean-based formulae are widely used although intolerance to soy has beenreported to occur in 15?40% of infants with CMA. We previously described across-reactivity between soy allergens and bovine caseins. We aimed to identifyB- and T-cell epitope-containing peptides from the P34 soy allergen to be usedin a mucosal vaccine-based immunotherapy for cow?s milk allergy.B-epitopes were mapped in the soy major allergen P34using specific antisera to bovine caseins and IgE-containing sera from CMApatients by spot membrane-based immunoassay. Amino acids shared by soybeanprotein P34 and bovine casein peptides were evaluated in silico. The selected synthetic peptides were synthesized andassessed for cell proliferation and cytokine production using splenocytes fromCMA mice and a human T-cell lines from CMA patients.We found that the C- and A-terminus portions of P34contained B- and T-epitopes, which was confirmed in silico. Then, 11 peptides spanning the Ct portion were selectedfor the next assays, based on IgE and T cell reactivity. T-cell lines and Tcell clones from CMA patients showed significant proliferative response againstP1, P2 and P3(p<.05), which exhibited a low IgE reactivity. In addition, P3showed the highest secretion of cytokines from splenocytes: IL-5 32±3 pg/ml,IL-13 223±42 pg/ml and IFN-γ 462±35 pg/ml, compared with cells incubated withmedium(p<.05).In conclusion, we identified a peptide from the major allergen of SoyP34 that could be used for the design of an oral vaccine to be used as atolerogenic immunotherapy for food allergy.