Novel Coronavirus Dodges Immune System as Easily as Common Cold Virus
The new coronavirus that has been linked to 12 infections worldwide can spread the infection and evade the immune system in humans just as easily as SARS or common cold virus, according to a new study; which means that it is fully prepared to infect many humans. The good news is that the virus can be treated with immunotherapy.
"Surprisingly, this coronavirus grows very efficiently on human epithelial cells," says co-author Volker Thiel of The Institute of Immunobiology at Kantonal Hospital in St. Gallen, Switzerland.
Although the new coronavirus, called HCoV-EMC, has recently jumped from animals to humans, it is well-adapted to cause infections in humans like other known viruses like the SARS virus and the common cold virus, HCoV-229E, Thiel said in a news release.
The first two cases of this coronavirus infection were confirmed Sept. 28, 2012. A man from Saudi Arabia and another from Qatar were the first two people identified with this novel strain. Recently, the U.K. reported four new cases of the new coronavirus, of which three were from the family.
Coronavirus belongs to a family of viruses that cause illness in animals and humans. The new strain of coronavirus was never detected in animals or humans so far. The new strain is "genetically quite distinct from SARS," WHO had said earlier.
Thiel and his team used bronchial cells grown in a lab to study the growth and spread of HCoV-EMC. The bronchial cells were tweaked to resemble the entry passage in the human body.
Study results showed that the first line of defense in human lungs, the epithelial cells, didn't stand a chance to infection from the HCoV-EMC. The study also found that the new virus grows faster than the SARS virus in the epithelial cells.
"The other thing we found is that the viruses [HCoV-EMC, SARS, and the common cold virus] are all similar in terms of host responses: they don't provoke a huge innate immune response," Thiel says. This is an indication that HCoV-EMC is already well adapted to the human host and that the virus uses the same strategy other coronaviruses use for evading the host's non-specific immune mechanisms.
However, treating the epithelial cells with lambda-type interferons can help the epithelial cells fight against the new coronavirus. Lambda-type interferons are proteins that are released by the cells of the host to begin a defense attack against the virus.
Authors of the present study noted that interferons have been known to help defend the body against SARS and Hepatitis C.
Thiel said that further research will show how the virus emerged and how many people are really affected by it. The spread of the new coronavirus is being observed carefully throughout the world because it is closely related to the SARS virus that infected more than 8,000 people between 2002 and 2003.
"We don't know whether the cases we observe are the tip of the iceberg. Or whether many more people are infected without showing severe symptoms," said Thiel.
The study is published in the journal mBio®.