Molecular basis of IgE cross-reactivity between human β-casein and bovine β-casein, a major allergen of milk

• Published in: Molecular immunology 2000-02, Vol.37 (3), p.161-167
• Main Authors: Bernard, H., Negroni, L., Chatel, J.M., Clement, G., Adel-Patient, K., Peltre, G., Creminon, C., Wal, J.M.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Allergens - immunology; Amino Acid Sequence; Animals; Antibody Specificity; b-casein; Binding, Competitive; Caseins - immunology; Cattle; Child; Child, Preschool; Cow’s milk allergy; Cross Reactions; Cross-reactivity; Enzyme-Linked Immunosorbent Assay; Human milk; Humans; IgE; Immunoglobulin E - immunology; Immunology; Life Sciences; Milk Hypersensitivity - immunology; Molecular Sequence Data; Peptide Fragments - immunology; Sequence Homology, Amino Acid; Species Specificity; β-casein
• ISSN: 0161-5890; 1872-9142
• DOI: 10.1016/S0161-5890(00)00029-8

Twenty patients allergic to cow’s milk proteins and with high levels of specific IgE directed against bovine whole casein were selected to evaluate reactivity of their IgE antibodies with human β-casein. Highly purified human and bovine β-caseins were prepared by selective precipitations and FPLC separation. Their identity and purity were assessed by HPLC, analysis of amino acid composition, sequencing of the five N-terminal amino acid residues and immunochemical tests. Direct and indirect ELISAs were performed using human and bovine β-casein coated into microtiter plates and monoclonal anti-human IgE antibody AChE labelled for revelation. Seven sera contained specific IgE directed against human β-casein. Inhibition studies using native human and bovine β-caseins as well as bovine β-casein-derived peptides demonstrated that, depending on the sera, one or several common epitopes located in different parts of the molecule were shared by the two homologous proteins.