“Allergy to Goat/Sheep’s Milk with Good Tolerance to Cow’s Milk but Not to Cow’s Milk Cheese: Identification of 1-105 Peptide from κ-Casein as the Molecular Basis of Reactivity toward Cow’s Milk Cheese

In Europe, a new population of patients developing anaphylaxis to goat’s/sheep’s milk associated to tolerance to cow’s milk has recently appeared. Nevertheless, among these patients, some show allergic reactions to cow’s milk cheeses but these reactions are less severe than those directed against goat’s/sheep’s milk. The objective of the study was to the molecular determinants of the reactivity of this category of patients toward goat’s/sheep’s milk and cow’s milk cheese. Western blots with either monoclonal antibodies specific of each casein or patients sera were performed. We confirmed that goat caseins are the main allergen recognized by patients with goat’s/sheep’s milk anaphylaxis. Patients IgE recognized also strongly and mainly bovine κ-casein 1-105 peptide which is present in cow’s milk cheese but not in cow’s milk. This peptide is generated by cleavage of κ-casein by chymosin during cheese fabrication. The reactivity of patients with anaphylaxis to goat’s/sheep’s milk toward cow’s milk cheese is due to the presence of an epitope in bovine κcasein 1-105 peptide, epitope absent or not accessible in full-length bovine κ-casein.