Covid-19 and HIV use same tactics to evade our immune systems – Chinese study

In rather worrying news, researchers in China are warning that similar characteristics and tactics used by both HIV and SARS-CoV-2 could mean that humanity will have to adapt to life with the coronavirus, perhaps indefinitely.

Both viruses remove markers, known as the major histocompatibility complex or MHC for short, on the surface of cells used by our immune systems to identify and kill infections. Think of these markers like a special forces team marking a target with a laser before a precision airstrike. 

The researchers, led by virologist Zhang Hui at Sun Yat-sen University in Guangzhou, collected killer T cells, immune cells produced by people after they have overcome an infection, from five recovered Covid-19 patients.

However, the killer T cells collected by researchers were ineffective, as the MHCs were missing, meaning that the patients’ immune systems would essentially be fighting blind were they to be re-infected in the future, making recovery just as difficult the second time as the first, while opening up the possibility of chronic infection. 

The coronavirus removes these markers by producing a protein known as ORF8 which binds to MHC molecules and pulls them inside an infected cell where it destroys them, making the cell appear normal to the immune system. This same ORF8 protein is used by a large number of commercial coronavirus test kits to detect viral loads in oral or nasal swabs. 

Zhang and his team propose the development of drugs “specifically targeting the impairment of MHC by ORF8, and therefore enhancing immune surveillance for Sars-CoV-2 infection.”

They also point out that the coronavirus displays “some characteristics of viruses [that cause] chronic infection” in their non-peer reviewed paper, posted on preprint website bioRxiv.org on Sunday, indicating that the coronavirus may be here to stay.

Previous studies identified yet another similarity between coronavirus and HIV; both share a protein spike which allows them to enter many types of human cells and bind to them, making them even more persistent than other types of infection. 

Zhang Shuye with the Shanghai Public Health Clinical Centre at Fudan University said the results were unsurprising and that viruses can share similar traits if they are exposed to similar selective pressures; for example, suppression of MHC molecules also occurs in viruses like herpes, which can persist throughout a person’s lifetime. 

“What we need to bear in mind through this pandemic is that, though the virus may have some traits that are new or unexpected, the majority of patients recover,” Zhang said. “This should give us some confidence.”

For comparison, as of 2018, approximately 37.9 million people are infected with HIV globally, while the death toll since the initial major outbreak in 1981 is believed to be around 32 million.  

However, mercifully, the coronavirus does not hijack T cells in order to reproduce, making it far less deadly than AIDS, the condition caused by HIV infection, and it also mutates at a much slower pace.

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