Key findings from the research
- An oral therapeutic vaccine candidate that enhances antiviral immunity against hepatitis C virus (HCV) and is expected to improve therapeutic effects of standard treatment regimens has been developed.
- Heat-killed, genetically-engineered probiotic Bifidobacterium bacteria are used.
- The vaccine candidate can be orally administered in a convenient manner, stably stored at room temperature, and used anywhere in the world, including developing countries.
- The vaccine candidate can be produced at a very low cost, and should reduce overall medical costs by improving the therapeutic effects of the costly standard treatment regimens when used in combination.
As a part of the research agenda of the Science and Technology Research Partnership for Sustainable Development (SATREPS) in partnership with Indonesia, in cooperation with Japan Science and Technology Agency (JST) and the Japan International Cooperation Agency (JICA), Professor Hak Hotta and Associate Professor Toshiro Shirakawa of Kobe University Graduate School of Medicine have successfully developed a therapeutic vaccine candidate for oral administration, which should improve the cure rate of standard treatment regimens for chronic hepatitis C.
Approximately 30% of the patients chronically infected with hepatitis C virus (HCV) cannot be cured by standard treatment regimens using pegylated interferon and ribavirin, with or without a newly approved antiviral protease inhibitor. Thus, more effective antiviral drugs should be developed to treat patients with HCV infection. Novel therapeutic agents are currently under development. While most of them target virus replication, few treatments to improve the cure rate by increasing host immunity against HCV have been developed.
The research group has developed an oral therapeutic vaccine candidate to enhance host immunity against HCV using a simple method: oral administration of probiotic Bifidobacterium bacteria contained in yogurt. Bifidobacterium bacteria genetically engineered to express HCV antigenic epitopes enhanced cell-mediated immunity against HCV when orally administered to mice. This therapeutic vaccine candidate should also have the probiotic effects of Bifidobacterium bacteria. The bacteria can be mass-produced at a very low cost and stably stored at room temperature. This oral vaccine candidate can be used as a safe and effective combination therapeutic agent for hepatitis C treatment to improve the cure rate of standard treatment regimens if its beneficial effects are confirmed in the necessary pre-clinical tests and clinical trials in the future. This vaccine candidate has an additional potential benefit; medical cost reduction by improving the overall cure rate, as well as low-cost production, brings benefits to the medical economy and even to developing countries where expensive drugs are difficult to obtain.
Outline of the research project
- Research area: Infectious Diseases Control
- Project title: Identification of Anti-Hepatitis C Virus(HCV) Substances and Development of HCV and Dengue Vaccines
- Principal Investigator: Professor, HOTTA Hak (Graduate School of Medicine/School of Medicine, Kobe University)
- Research period: FY2009-FY2013
- doi: 10.1016/j.vaccine.2014.03.022
Contacts
Concerning the research:
HOTTA Hak
Professor, Graduate School of Medicine/School of Medicine, Kobe University
E-mail: 
Concerning the SATREPS program (JST):
Research Partnership for Sustainable Development Division
Japan Science and Technology Agency
E-mail: 
Concerning the SATREPS program (JICA):
Office of Media and Public Relations
Japan International Cooperation Agency
E-mail: 
Notes and terminology
Note 1: SATREPS
SATREPS (Science and Technology Research Partnership for Sustainable Development) is a Japanese government program that promotes international joint research to address global issues through three- to five-year projects involving partnerships between researchers in Japan and researchers in developing countries. The program is collaboration between Japan Science and Technology Agency (JST) and the Japan International Cooperation Agency (JICA). JST uses research contracts to support research costs incurred in Japan (and in other locations outside the developing country involved in the project). JICA provides support through its technical cooperation project framework to cover costs in the developing country. Overall R&D management of the international joint research is handled jointly by JST, which has expertise in funding research projects at research institutions in Japan, and JICA, which has expertise in technical cooperation in developing countries.
Details are available at the JST website: http://www.jst.go.jp/global/english/about.html