Biochemical characterization by two‐dimensional electrophoresis of lymphocyte antigens involved in cell‐to‐cell or cell‐to‐matrix adhesion

Abstract

We have exemplified three cases of application of two‐dimensional (2‐D) electrophoresis to the characterization of lymphocyte membrane antigens. We could show that the proteins recognized by two monoclonal antibodies, LAK1 and LAK2, on the surface of large granular cells mediating natural‐ and lymphokineactivated killing are distinct molecules. LAK1 is expressed without any structural modification, even on the surface of endothelial cells. Another membrane antigen, recognized by the monoclonal antibody FB 12, was shown to have the overall structure of the integrins of the very late activation (VLA) class, being composed of an α and of a β subunit. The latter corresponded to the β1 type as already characterized for other VLAs, whereas the α chain was different from α1 through α6. The 2‐D protocol using immobilized pH gradients for the first dimension allows reliable assessment of the identity of individual components because of the reproducibility of the absolute coordinates for spot position.