ABSTRACT
The mechanisms involved in virus-induced severe hepatitis have not been fully elucidated.In this study,we investigated the role of gamma delta T cell receptors (γδ) T cells in the pathogenesis of fulminant viral hepatitis (FVH) induced by murine hepatitis virus strain 3 (MHV-3).The model of FVH was established by intraperitoneal injection of MHV-3 into Balb/cJ mice.The survival days of mice,and the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were examined.The proportions ofγδ T cells in blood,spleen and liver,and cytokines secreted by hepatic γδ T cells were analyzed by flow cytometry.The function of hepatic γδ T cells was examined by cytotoxicity assay.Balb/cJ mice died in 3 to 6 days post MHV-3 infection,with severe hepatic necrosis and significant augmentation of serum ALT and AST levels.The proportions of γδ T ceils in blood,spleen and liver were significantly increased post MHV-3 infection,while those of the early activating molecule CD69-expressing γδ T cells and productions of cytokines tumor necrosis factor-alpha (TNF-α) and interferon-γ (IFN-γ) increased remarkably in the liver.These highly activated liver γδ T cells were cytotoxic to MHV-3-infected hepatocytes in vitro and this effect of liver γδ T cells against hepatocytes might involve the TNF-α and IFN-γ pathway.These results demonstrated that γδ T cells might contribute to the pathogenesis ofMHV-3-induced FVH through the effector cytokines TNF-α and IFN-γ.
ABSTRACT
The mechanisms involved in virus-induced severe hepatitis have not been fully elucidated.In this study,we investigated the role of gamma delta T cell receptors (γδ) T cells in the pathogenesis of fulminant viral hepatitis (FVH) induced by murine hepatitis virus strain 3 (MHV-3).The model of FVH was established by intraperitoneal injection of MHV-3 into Balb/cJ mice.The survival days of mice,and the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were examined.The proportions ofγδ T cells in blood,spleen and liver,and cytokines secreted by hepatic γδ T cells were analyzed by flow cytometry.The function of hepatic γδ T cells was examined by cytotoxicity assay.Balb/cJ mice died in 3 to 6 days post MHV-3 infection,with severe hepatic necrosis and significant augmentation of serum ALT and AST levels.The proportions of γδ T ceils in blood,spleen and liver were significantly increased post MHV-3 infection,while those of the early activating molecule CD69-expressing γδ T cells and productions of cytokines tumor necrosis factor-alpha (TNF-α) and interferon-γ (IFN-γ) increased remarkably in the liver.These highly activated liver γδ T cells were cytotoxic to MHV-3-infected hepatocytes in vitro and this effect of liver γδ T cells against hepatocytes might involve the TNF-α and IFN-γ pathway.These results demonstrated that γδ T cells might contribute to the pathogenesis ofMHV-3-induced FVH through the effector cytokines TNF-α and IFN-γ.
ABSTRACT
To evaluate the role of murine fibrinogen like protein 2 (mfgl2) /fibroleukin in lung impairment in Severe acute respiratory syndrome (SARS), a murine SARS model induced by Murine hepatitis virus strain 3 (MHV-3) through trachea was established. Impressively, all the animals developed interstitial pneumonia with extensive hyaline membranes formation within alveoli, and presence of micro-vascular thrombosis in the pulmonary vessels. MHV-3 nucleocapsid gene transcripts were identified in multiple organs including lungs, spleen etc. As a representative proinflammatory gene, mfgl2 prothrombinase expression was evident in terminal and respiratory bronchioles, alveolar epithelia and infiltrated cells in the lungs associated with fibrin deposition and micro-vascular thrombosis. In summary, the established murine SARS model could mimic the pathologic characteristics of lungs in patients with SARS. Besides the physical damages due to virus replication in organs, the up-regulation of novel gene mfgl2 in lungs may play a vital role in the development of SARS associated lung damage.