JERUSALEM, Israel (Xinhua) -- Israeli scientists have discovered how the COVID-19 virus evades the human immune system, the Weizmann Institute of Science (WIS) in central Israel said on Thursday.In a study published in the journal Nature, researchers from the WIS and the Israel Institute for Biological Research (IIBR) revealed a unique combination of three molecular mechanisms, or arms, by which the virus overcomes the immune system.The researchers also identified the viral proteins involved in these mechanisms, which could lead to new effective therapies.These mechanisms allow the virus to quickly take control of the host cell's protein production system, prevent the recruitment of the immune system, and then multiply without interruption.The first arm allows the virus to dramatically reduce the protein production capacity in the cell.The second arm actively and selectively breaks down the cell's messenger RNA (mRNA) molecules, which carry the protein production recipes.At the same time, the unharmed viral mRNA molecules continue on their way to the production lines.The third arm allows the virus to block new RNA molecules, produced in response to the viral invasion, from exiting the cell nucleus.This prevents the cell from fighting the virus and calling for outside help.This causes a significant delay in the immune system's response, which may lead to deterioration in the patient's condition and even cause death.