The recognition pattern of sequential B cell epitopes of beta-lactoglobulin does not vary with the clinical manifestations of cow's milk allergy

BACKGROUND: beta-Lactoglobulin (BLG) represents one of the major allergens causing cow's milk allergy (CMA) - a disease with a wide spectrum of clinical symptoms. The aim of this study was to evaluate sequential B cell epitopes of BLG by the Pin-ELISA method. Furthermore, we wanted to investigate a possible association of the IgE recognition patterns in sera of patients with BLG sensitization and the type of clinical reactions following contact with cow's milk. METHODS: Overlapping sequential decapeptides corresponding to the amino acid sequence of BLG were used in Pin-ELISAs specific for human IgE. Tested sera were from 14 individuals with CMA, 8 of them with a history of immediate systemic reactions and 6 with delayed skin reactions following contact with cow's milk. All of them showed specific IgE antibodies to BLG in the CAP-RAST. Control sera were from 5 healthy nonallergic individuals. RESULTS: All sera from BLG-sensitized individuals showed IgE binding with one region of BLG corresponding to amino acids 95-113. Furthermore, individual sera showed reactions with two further regions, 12-27 and 124-135. Inhibition of IgE binding to BLG with one soluble synthetic peptide confirmed the major epitope. No differences were found in the B cell epitope recognition pattern to BLG in the two groups of patients with CMA, characterized by acute systemic or delayed skin reactions. CONCLUSIONS: Using IgE Pin-ELISAs we were able to confirm previously described sequential B cell epitopes of BLG. However, the recognition pattern of one of the major cow's milk allergens is not predictive of the clinical type of reaction.