Vascular Smooth Muscle Cells and Foreskin Fibroblasts: A Study on Normal Individuals and a Patient With Glanzmann’s Thrombasthenia

The cytoadhesin family consists of platelet glycoprotein (GP) lIb-Illa and the endothelial vitronectin receptor. The $ subunit (GP lIla) of these complexes expresses the alloantigen Zw (or Pl ). This alloantigen is not expressed by members of other integrin subfamilies. By using immunoprecipitation and immunoblot techniques. we found that the /9 subunit of a heterodimer. expressed by cultured human arterial smooth muscle cells and cultured foreskin fibroblasts. carries the Zw antigenic determinant. Furthermore. the mobilities of the a and fi subunits of these two heterodimers are indistinguishable from those of the a and j9 subunits of the endothelial vitronectin receptor. Therefore. we propose that the smooth muscle cell and fibroblast heterodimer are members of the cytoadhesin family. In Glanzmann’s thrombasthenia. platelet GP lIb-Illa is absent or severely reduced. Previously. we showed that endothe-