Identical allotypic markers of heavy polypeptide chains present in different immunoglobulin classes.

Abstract

Purified IgA molecules, prepared from rabbit colostrum, have the same allotypic markers of the heavy (H) polypeptide chain as are present in the serum IgG of the same individual. When the dimeric molecule of rabbit colostral IgA is dissociated into its sub-units by reduction, its capacity to absorb an appropriate anti-allotypic antibody is quantitatively identical with that of the serum IgG of the same animal. It is concluded that there are neither qualitative nor quantitative differences in the antigenic expression of the allotypic determinants of the a locus present on the rabbit γ and α chains.