ABSTRACT
Pathophysiological mechanism of hemorrhagic fever with renal syndrome (HFRS) is not fully understood. Major clinical findings of HFRS patients are widespread hemorrhage, acute renal failure and shock. Basic lesion is vascular injury with microvascular hemorrhage and relatively little inflammation. According to autopsy findings, renal medulla shows focal hemorrhage, tubular necrosis and interstitial mononuclear infiltrates. The predominant cell type in the renal and pulmonary interstitium is a fibroblast and it participates in the healing process at the injury site by secreting a large amount of extracellular matrix proteins. Cultured human lung fibroblasts and Mongolian gerbil fibroblasts were known to be good host cells for the hantaan virus. It is possible that not only the endothelial cell but also the fibroblast is a target of Hantaan virus and the fibroblast might be involved in the pathogenesis and the healing process in HFRS. Integrins are adhesion molecules, and act as receptors for many extracellular matrix proteins. Recently, there are many reports that cell surface integrins influence on some viral infections or reversely viruses influence on the expression of integrins. The alpha5beta1 integrin is a major receptor for the fibronectin which is an important extracellular matrix protein secreted by fibroblasts. In this study, the role of alpha5beta1 integrin in the infection of Hantaan virus was examined by using anti-alpha5beta1 integrin, anti-alpha5 integrin and anti-beta1 integrin antibodies in chicken embryo fibroblasts (CEF) and Mongolian gerbil fibroblasts(MGF). The treatment of anti-alpha5beta1 integrin antibody in CEF reduced the virion titers 26.8% and the amount of nucleocapsid N protein 32.6% when compared with control CEF. When MGF were treated with anti-alpha5, anti-beta1 and anti-alpha5beta1 integrin antibodies, virion titers were reduced by 26.5%, 29.4% and 28.7% and the amount of nucleocapsid N protein were reduced by 65.2%, 59.7% and 72.6%. These results suggested that alpha5beta1 integrin might act as a receptor for the Hantaan virus or blocking of alpha5beta1 integrin influences on the viral replication in CEF and MGF. It is also possible that the blocking of only one subunit of integrin represents similar results in that of whole molecule.