1989 Fiscal Year Final Research Report Summary
Study on the relationship between the expression of HBV X gene and type B hepatitis or hepatocellular carcinoma
| Project/Area Number |
62440037
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Gastroenterology
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
KAMADA Takenobu Osaka University Medical School Professor, 医学部, 教授 (80028399)
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| Co-Investigator(Kenkyū-buntansha) |
KATAYAMA Kazuhiro Osaka University Hospital Staff, 医学部附属病院, 医員
SASAKI Yutaka Osaka University Hospital Staff, 医学部附属病院, 医員
KASAHARA Akinori Osaka University Medical School Assistant, 医学部, 助手 (70214286)
HAYASHI Norio Osaka University Medical School Lecturer, 医学部, 講師 (00144478)
SATO Nobuhiro Osaka University Medical School Lecturer, 医学部, 講師 (90028358)
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| Project Period (FY) |
1987 – 1989
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| Keywords | type B hepatitis / HBV / X-gene / hepatoma / hepatocytotoxity / HBxAg / anti-HBx / viral replication |
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| Research Abstract |
We studied the expression of heptitis B virus (HBV) X-gene in patients with type B heptitits. The almost complete region of HBV X-gene was expressed in Escherichia coli. Sera were analyzed by Western blot analysis. Anti-X was not found in patients with acute hepatitis and healthy carriers, but was present in those with chronic hepatitis, liver cirrhosis and hepatocellular carinoma. In order detect X products in liver tissues, we used indirect immunohistochemical method. X antigens (HBxAg) were expressed in cytoplasm of hepatocytes, and were not found when the anti-X was present. These findings suggested that HBxAg was expressed in the early stage of chronic HBV infection. Furthermore, there was a significant correlation between the expression of HBcAg and HBxAg, suggesting that HBxAg promotes the replication of HBV. Our studies have also reported that Pre-S antigen of HBV was required for the assembly of Dane particle (HBV particle), and that HBV replication was active when Pre-S antigen was expressed on the membrane of hepatocytes. Thus, both HBxAg and Pre-S antigen seem to be in close relations to HBV replication. In two patients with hepatocellular carcinoma, HBxAg was not expressed in cancerous region, but was expressed in noncancerous region next to hepatocellular carcinoma. These findings suggested that HBxAg was required for the hepatocareinogenesis, not for the maintenance of hepatoma.
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