Asialoagalactothyroglobulin binds to the surface of human thyroid cells at a site distinct from the 'microsomal' autoantigen.

Human thyroglobulin has been shown for the first time to bind to the surface of cultured human thyroid follicular cells. Binding was only observed with partially glycosylated asialoagalactothyroglobulin, not with the fully glycosylated iodoprotein. The binding site for asialoagalactothyroglobulin in the cell membrane is distinct from membrane associated microsomal/microvilli antigen. Since asialoagalactothyroglobulin bears the autoantigenic determinants of the parent molecule, its ability to bind to the thyroid cell surface suggests a possible role for this protein in the pathogenesis of human thyroiditis.