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Original Article
 

IgE Cross Reactivity Between Reindeer and Bovine Milk ß-Lactoglobulins in Cow’s Milk Allergic Patients
 

TJ Suutari,1 KH Valkonen,1 TJ Karttunen, 2 B-M Ehn, 3 B Ekstrand, 3 U Bengtsson, 4 V Virtanen, 1 M Nieminen, 5 J Kokkonen 6

1 Laboratory of Biotechnology, Kajaani University Consortium, University of Oulu, Sotkamo, Finland
2 Department of Pathology, University of Oulu, Oulu, Finland
3 SIK-The Swedish Institute for Food and Biotechnology, Gothenburg, Sweden
4 Department of Respiratory Medicine and Allergology, The SahLgrenska Academy at Gothenburg University, Gothenburg, Sweden
5 Finnish Game and Fisheries Research Institute, Reindeer Research Station, Kaamanen, Finland
6 Department of Children and Adolescents, Oulu University Hospital, Oulu, Finland

J Investig Allergol Clin Immunol 2006; Vol. 16(5): 296-302
 

 Abstract


Background: Allergic reactions to cow’s milk are common in small children. One of the main protein allergens found in cow’s milk is ß-lactoglobulin (ß-Lg). Reindeer and bovine milk both contain related ß-Lg proteins, but the allergenicity of reindeer ß-Lg has not previously been studied. The purpose of this study was to analyze the immunological cross-reactivity of IgE antibodies from children with cow’s milk allergy to reindeer and bovine ß-Lg.

Methods: Sera from 17 children and a serum pool of 4 patients with elevated cow’s milk-specific IgE were investigated. ß-Lg from bovine and reindeer milk was isolated in native form and an enzyme-linked immunosorbent inhibition assay was developed. Bovine ß-Lg was used as a capturing antigen and the inhibiting effects of reindeer and bovine ß-Lg on the IgE binding were measured.

Results: Cross-reactivity patterns of bovine milk ß-Lg specific IgE to reindeer ß-Lg varied among patients. In general, reindeer ß-Lg showed significantly lower inhibition (mean 43%) of IgE binding to the capturing antigen than did bovine ß-Lg (mean 89%). In some patients, even high concentrations of reindeer ß-Lg only partly eliminated the IgE binding to bovine ß-Lg.

Conclusions: The partial cross-reactivity of human anti-bovine IgE with reindeer ß-Lg suggests that it lacks important bovine epitopes and those that are recognized are only weakly bound.

Key words: Cow’s milk allergy. Reindeer milk. ß-lactoglobulin. ELISA inhibition.