Development of a novel polyclonal antibody against bovine _S1-casein IgE epitopes for prediction of potential allergenicity of milk in foods

Bovine a(S1)-casein (a(S1)-CN) is the main allergen in cow's milk, and immunoglobulin E (IgE) epitopes are the material basis to trigger allergic reactions. Thus, IgE epitopes could be as key targets for precise a(S1)-CN detection and allergenicity assessment. Here, we designed a tandem containing nine IgE linear epitopes of a(S1)-CN (ta(S1)-CN), expressed the recombinant ta(S1)-CN in Escherichia coli, and prepared the rabbit polyclonal antibody against recombinant ta(S1)-CN (pAb-ta(S1)-CN). The obtained recombinant ta(S1)-CN had a purity of 94.43% and retained the antigenicity and potential allergenicity of IgE epitopes. The pAb-ta(S1)-CN could recognize the nine IgE epitopes of a(S1)-CN, and also showed high specificity. The ability of pAb-ta(S1)-CN to evaluate the potential allergenicity of milk in foods was validated by sera from cow's milk allergy patients. These findings indicate that our prepared pAb-ta(S1)-CN may represents a valuable tool for the evaluation of milk allergenicity in processed foods.