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The novel coronavirus uses the same strategy to evade attack from the human immune system as HIV, according to a new study by Chinese scientists.

Both viruses remove marker molecules on the surface of an infected cell that are used by the immune system to identify invaders, the researchers said in a non-peer reviewed paper posted on preprint website bioRxiv.org on Sunday. They warned that this commonality could mean Sars-CoV-2, the clinical name for the virus, could be around for some time, like HIV.

Virologist Zhang Hui and a team from Sun Yat-sen University in Guangzhou also said their discovery added weight to clinical observations that the coronavirus was showing "some characteristics of viruses causing chronic infection".

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Their research involved collecting killer T cells from five patients who had recently recovered from Covid-19, the disease caused by the virus. Those immune cells are generated by people after they are infected with Sars-CoV-2 - their job is to find and destroy the virus.

But the killer T cells used in the study were not effective at eliminating the virus in infected cells. When the scientists took a closer look they found that a molecule known as major histocompatibility complex, or MHC, was missing.

The molecule is an identification tag usually present in the membrane of a healthy cell, or in sick cells infected by other coronaviruses such as severe acute respiratory syndrome, or Sars. It changes with infections, alerting the immune system whether a cell is healthy or infected by a virus.

HIV uses the same strategy - MHC molecules are also absent in cells infected with that virus.

"In contrast, Sars does not make use of this function," Zhang said.