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CTL-Associated Antigen-4 Immunoglobulin (CTLA4Ig) Suppresses Liver Damage in New Mouse Model of Acute Hepatitis B Infection
A promising new avenue for treating hepatitis B has been reported by researchers at Hiroshima University in Japan who have developed a new animal model of the disease. Approximately two million people worldwide have been exposed to hepatitis B virus. Liver transplantation is often necessary to save the lives of patients who have severe liver damage that results from acute overreaction of the immune system. To develop therapies against acute hepatitis, an appropriate animal model is necessary. “The number of patients who can receive liver transplantation is limited, so there is an urgent need to develop new treatment options,” said Professor Kazuaki Chayama of Hirioshima University. Professor Chayama and his research group used mice with so-called “humanized” livers, and injected them with human blood. They found that hepatitis in these “human hepatocyte chimeric mice” was caused by white blood cells known as cytotoxic T lymphocytes (CTLs) that were specifically targeted to hepatitis B virus. This was very similar to human acute hepatitis B. The researchers also found that treating the mice with a molecule called CTL-associated antigen-4 immunoglobulin (CTLA4Ig) suppressed damage to liver cells infected with hepatitis B virus, suggesting that this might be a potential approach to treatment in humans. The mouse model should also be useful for studying the immunological reactions and viral clearance in hepatitis B virus infection, the authors note in their article posted online on August 5, 2015 in the Journal of Virology.