Insulin autoantibodies with high affinity to the bovine milk protein alpha casein.
Clin Exp Immunol
; 164(1): 42-9, 2011 Apr.
Article
em En
| MEDLINE
| ID: mdl-21361910
ABSTRACT
Insulin autoantibodies (IAA) can appear in children within months of introducing solid foods to the diet and before clinical type 1 diabetes. The aim of this study was to determine whether infant dietary antigens could be immunizing agents of IAA. To this end, IAA binding to [(125) I]insulin was competed with food preparations and extracts of foods encountered in the infant diet (milk formulas, bovine milk, wheat flour, fowl meal). Bovine milk powder extracts inhibited IAA-positive samples from six of 53 children (age 0·3-14·0 years) participating in German prospective cohorts. Inhibition in these sera ranged from 23 to 100%. Competition was abolished when hydrolyzed milk powder was used. Competition with protein components of bovine milk found that two of the six milk-reactive sera were inhibited strongly by alpha- and beta-casein; none were inhibited by the milk proteins bovine serum albumin or lactoglobulins. The two casein-reactive sera had high affinity to alpha-casein (1·7×10(9) ; 3·1×10(9) l/mol), and lesser affinity to beta-casein (4·0×10(8) ; 7·0×10(7) l/mol) and insulin (2·6×10(8) ; 1·6×10(8) l/mol). No children with milk-reactive IAA developed autoantibodies to other islet autoantigens or diabetes (median follow-up 9·8 years). These results suggest that autoimmunity to insulin can occur infrequently via cross-reactivity to food proteins, but this form of IAA immunization does not appear to be associated with progression to diabetes.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Autoanticorpos
/
Caseínas
/
Insulina
/
Anticorpos Anti-Insulina
Limite:
Adolescent
/
Animals
/
Child
/
Child, preschool
/
Humans
/
Infant
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article