Orientation of cell-surface antigens in the lipid bilayer of lymphocyte plasma membrane

Abstract
Human HLA-A, B, C and Ia antigens were labelled by lactoperoxidase-catalysed iodination of the inner surface of lymphocyte plasma membrane and thus are transmembrane proteins. In contrast, membrane-bound human IgM and mouse IgM, IgD and Thy-1 antigen were not labelled on the inner membrane surface.