ALLERGENICITY OF ALPHA-CASEINS FROM COW, SHEEP, AND GOAT

The allergic potential of alpha-caseins from bovine, ovine, and goat's milk sharing more than 85% identical amino acids was compared. Casein s were purified by anion-exchange chromatography and used for a specif ic IgE and IgG ELISA with diluted human sera. Sera were from 17 childr en with immediate-type allergy to cow's milk, from 59 children with at opy but without food allergy, and from 27 healthy children without ato pic disease. The sera of cow's milk-allergic children showed a signifi cantly higher IgE and IgG binding to alpha-caseins from all three spec ies than the sera of the other groups. All groups showed an increased antibody binding to bovine alpha-casein compared to the sheep and goat proteins, but the differences were significant only in the groups of atopic children and of healthy controls. Furthermore, inhibition of th e IgE binding to bovine alpha-casein with alpha-casein from cow, goat, and sheep revealed that the alpha-caseins from these species are high ly cross-reactive, on the basis of the small differences in their prim ary structure. In conclusion, the milk of goat and sheep harbor an all ergic potential and is not suitable for the nutrition of milk-allergic patients.