More than three percent of the world’s population are chronically infected by the hepatitis B virus. As a result, every year, 880,000 people worldwide die of liver failure or hepatocellular carcinoma. Last month, Prof. Ulrike Protzer, head of the Institute of Virology at Helmholtz Zentrum München and TUM shared some interesting news coming from her lab.
Using a preclinical mouse model, Prof. Ulrike Protzer and her team found that proteins of the hepatitis B virus prevent that certain immune cells of the body, so-called CD8+ T-cells, become effective. Based on these findings, the scientists developed a novel therapeutic approach: first, the expression levels of the virus proteins are knocked down, and then the immune cells are activated by therapeutic vaccination. In contrast to conventional vaccinations, which aim to prevent diseases before outbreak, such a therapeutic vaccination aims to cure already existing chronic diseases.
Using siRNAs, small ribonucleic acid molecules, scientists developed a method to suppress the hepatitis B virus proteins. The siRNAs molecules bind to the messenger RNA of the virus’ proteins. By labeling the messenger RNA with siRNA, the infected cell receives the signal that the viral RNA is undesired and removes it. In any case, the suppression of protein expression alone was not sufficient to reverse the inhibition of the CD8+ T-cells in chronically infected mice. For that reason, they combined the siRNA method with a therapeutic vaccination developed by them, enabling them to trigger a strong immune response against the virus and cure hepatitis B virus infection in two different mouse models.
The newly developed vaccine, called TherVacB, will be tested as immunotherapy in a two-year clinical trial starting in 2021. It is designed to cover the majority of all hepatitis B viruses and can therefore be used worldwide for infected people.
Original publication is available here.