Bovine beta-casein antibodies in breast- and bottle-fed infants: their relevance in Type 1 diabetes

Background Bovine beta -casein is a cow's milk protein that targets both humoral and cellular immune responses in patients with Type 1 diabetes and, to a lesser degree, also in normal subjects. In this study we aimed to determine whether the avoidance of cow's milk consumption early in life could prevent the development of antibody response to bovine beta -casein despite the mother being exposed on a daily basis to cow's milk consumption. Materials and Methods We measured the antibody response to bovine beta -casein using an ELISA method in 28 healthy infants under 4 months of age, of whom 16 were exclusively breast-fed and 12 were bottle-fed with cow's milk. In addition, beta -casein antibodies were measured in 37 prepubertal children with Type 1 diabetes and in 31 healthy children who were exposed to cow's milk or dairy products to see whether differences in antibody titers exist in this young age group. Antibodies binding to beta -casein were also evaluated by immunoblotting analysis. Results Elevated levels of beta -casein antibodies were found in bottle-fed infants compared to breast-fed infants (p < 0.0001). Antibody levels to bovine <beta>-casein were also significantly higher in children with Type 1 diabetes compared to age-matched controls (p = 0.03). By western blot analysis we confirmed specific binding to bovine beta -casein in bottle-fed infants, in children with Type 1 diabetes and in controls exposed to cow's milk, but not in infants who were exclusively breast-fed. Conclusions The results of this study indicate that breastfeeding within the first 4 months of life prevents the generation of antibody response to bovine beta -casein despite the mothers' consumption of cow's milk during the breastfeeding period. These findings may have relevance for disease prevention. Copyright (C) 2000 John Wiley & Sons, Ltd.