Japanese Researchers Discover SARS-CoV-2 Enzyme That Evades Innate Immune Response
Researchers from Kobe University in Japan have made a significant discovery regarding SARS-CoV-2, the virus responsible for Covid-19, revealing that it possesses an enzyme capable of undermining the body’s innate defense mechanisms against viral infections. This finding provides insight into why Covid-19 is more contagious than earlier coronaviruses, such as those causing SARS and MERS.
The study focused on a molecular tag known as “ISG15,” which plays a crucial role in preventing the nucleocapsid proteins of the virus from assembling—an essential step for virus formation. Virologist Shoji Ikuo and his team found that the enzyme associated with SARS-CoV-2 can effectively remove these ISG15 tags from its nucleocapsid proteins, thereby restoring the virus’s ability to assemble new particles and evade the innate immune response.
While both the SARS and MERS viruses also carry similar enzymes capable of removing the ISG15 tag, the researchers noted that these versions are less efficient than that of SARS-CoV-2. “The results suggest that the novel coronavirus is simply better at evading this aspect of the innate immune system’s defense mechanism, which explains why it is so infectious,” said Shoji.
The innate immune system serves as the body’s first line of defense, limiting viral entry, replication, and the assembly of new viruses. Unlike its predecessors, the Covid-19 virus has rapidly spread across the globe, even reaching the remote regions of Antarctica. Despite ongoing mutations and the emergence of new variants, the severity of the disease has been mitigated through widespread vaccination and herd immunity.
These findings hold promise for the development of more effective antiviral treatments for Covid-19 and similar future diseases. “We may be able to develop new antiviral drugs if we can inhibit the function of the viral enzyme that removes the ISG15 tag,” the researchers concluded. Future therapeutic strategies might also include agents that directly target the nucleocapsid protein or a combination of these approaches, paving the way for innovative treatments in the fight against viral infections.
