Development of Large Scale Expression, Preparation, and Highly Sensitive Immunoassay Methods for Hepatocyte Growth Factor

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Hepatocyte growth factor (HGF) has mitogenic, and morphogenic activities for various types of epithelial cells, including mature hepatocytes. In 1989, we succeeded in molecular cloning of HGFcDNA and elucidated primary structure of HGF. Although HGF has been considered to act as hepatotrophic factor for liver regeneration, we recently found that HGF acts as renotropic act as renal regeneration. In the present study, we have succeeded in the development of large scale expression and preparation of recombinant HGF, and highly sensitive immunoassay for HGF, as follows:(1) The expression vector for human HGF was transfected in mammalian cells and we obtained cell line which produces recombinant human HGF in extremely large scale (10 mg/l). Thus method for large scale preparation of HGF has been established. (2) Using polyclonal and monoclonal antibodies to human HGF, we established highly sensitive immunoassay method for human HGF. (3) We also established methods for large scale preparation of rat HGF and its highly sensitive immunoassay. (4) We found HGF levels in sera of patients with hepatitis, partial hepatectomy, acute renal failure, renal carcinoma, lung cancer, and pneumonia are much higher than those in healthy persons. (5) We obtained direct evidence that HGF acts as hepatotrophic and renotropic factor, when recombinant HGF was intravenously injected into experimental animals subjected to various types of hepatic of renal injuries, HGF remarkably stimulated hepatic and renal regeneration. All these results indicate that HGF may prove to be a an useful treatment to accelerate and renol regeneration and also to be an diagnostic marker for various organ diseases. Therefore we expect that HGF will make great contributions not only for basic sciences but also for clinical medicine.