Human IgE binding to the glycosidic moiety of bovine kappa-casein.

IgE ability for recognizing milk proteins was assayed in the serum of an adult atopic patient who outgrew cow milk allergy in early childhood. A number of protein species included in casein from bovine milk were detected by human IgE in immunoblotting experiments. Comparing these results with those obtained from an analysis using antibody preparations specifically directed toward the different casein fractions, IgE-reactive bands were identified as isoforms of kappa-casein. IgE-reactive protein was not present in neither bovine cheese, regardless of cheese-making technology and time ripening, nor milk from any other dairy animal, such as ewe, goat, and water buffalo. Chemical deglycosylation of protein bands immobilized onto nitrocellulose proved that the glycosidic moiety of bovine kappa-casein was principally involved in IgE recognition.