INJURY MODELS OF THE VASCULAR ENDOTHELIUM - APOPTOSIS AND LOSS OF THROMBORESISTANCE INDUCED BY A VIRAL PROTEIN

Endothelial injury caused by viruses usually involves viral replicatio n or transformation. We report a novel mechanism of endothelial damage by a toxic viral protein. We have isolated a new retrovirus from hema ngiosarcomas which appeared among layer hens. The isolated avian heman giosarcoma virus (AHV) is capable of inducing hemangiomas in hens in-v ivo and causes a cytopathic effect (CPE) and loss of thromboresistance in cultured bovine aortic endothelial cells (BAEC). These effects do not require viral replication and can be induced by purified AHV envel ope glycoprotein (gp85). AHV causes CPE in BAEC through a typical prog rammed cell death (apoptosis). Quiescent G0/G1-BAEC are much more sens itive to AHV induced apoptosis than actively dividing cells. These exp eriments demonstrate the capacity of viral proteins to affect the inte grity and functionality of vascular endothelial cells.