Abstract: α-Lactalbumin represents one of the major allergens causing cow milk allergy. The identification of the epitopes of α-lactalbumin and the critical amino acids for its allergenicity is of great significance for understanding the mechanism of action of α-lactalbumin and developing hypoallergenic dairy products. In this study, a series of peptides were synthesized by a solid phase method for the characterization of immunological epitopes and critical amino acids. The immunoglobulin (Ig) E-binding epitopes were immunolabeled with individual sera from cow milk-allergic patients as probes by enzyme linked immunosorbent assay (ELISA). Alanine scanning of immunodominant epitopes was used to identify the critical amino acids (aa). The results showed that IgE-binding epitopes were located within the sequences of aa1-15, aa6-20, aa46-60, aa71-85 and aa101-115. Our initial data revealed that Val8, Phe9, Arg10, Tyr103, Leu105 and His107 were the critical amino acids for IgE-binding epitopes. This study will provide the necessary information to alter the cDNA to encode a protein capable of activating milk-specific T cells, but with reduced IgE-binding capacity.

Key words: cow milk allergy, α-lactalbumin, epitope, critical amino acid