AsianScientist (May 19, 2017) – Researchers from the Institute of Biophysics of the Chinese Academy of Sciences have identified a protein fragment that could be used to create a more effective vaccine against the hepatitis B virus (HBV), one that can even treat chronically infected individuals. Their findings have been published in Hepatology.
More than two billion people are infected with the hepatitis B virus worldwide, 350 million of whom go on to become chronic HBV carriers. Nearly one million people die from hepatitis B-related diseases every year. Persistent HBV infection represents a substantial threat to the public health, despite the existence of effective prophylactic vaccines. There is an urgent need for effective treatment strategies to limit the enormous burden of viral hepatitis on global health.
One of the challenges of treating chronic HBV infections is that the vaccine currently in use (against HBsAg) generates immune tolerance rather than a protective response. In the present study, a research group led by Dr. Fu Yangxin and Dr. Peng Hua showed that the preS1 domain of the HBV large surface antigen could be used to treat chronic HBV infections by lowering immune tolerance to HBV.
Using a HBV carrier mouse model, they showed that unlike the main immune stimulating protein fragment linked to chronic infections, the preS1 domain was able to avoid tolerance and generate a stronger protective response, inducing a robust immune response in the mice.
The antibodies against the preS1 domain were able to clear HBV virions and block HBV infection of hepatocytes. The vaccination even reduced the tolerized status against the existing vaccine antigen HBsAg, opening a therapeutic window for the host to respond to the vaccine.
By first administering the preS1 vaccine followed by the HBsAg vaccine, the researchers were able to induce the production of protective antibodies, a clinical indicator of a cure for chronic HBV infection. These results suggest the preS1 domain is a promising therapeutic vaccine against chronic HBV infection.
The article can be found at: Bian et al. (2017) Vaccines Targeting PreS1 Domain Overcome Immune Tolerance in HBV Carrier Mice.
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Source: Chinese Academy of Sciences; Photo: Shutterstock.
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