US virologist says SARS-CoV-2 virus can debilitate immune system
11 November 2020
The Wuhan virus, also called the novel coronavirus and now Covid-19 or SARS-CoV-2 can debilitate the immune system of the affected person and disable the patient in fighting off the infection, according to virologists at the Icahn School of Medicine at Mount Sinai in East Harlem, in the United States.
According to Benjamin tenOever who headed a team of researchers that studied the nature of the novel coronavirus in an isolated laboratory at the Icahn School of Medicine, a SARS-CoV-2 attack can damage the immune system like no other virus.
The Icahn researchers have found that SARS-CoV-2 disrupts the cellular programming activity whereby each cell in our body shares the same DNA to make proteins with the single-strand RNA acting as software.
The disruption of the cellular programming by SARS-CoV-2 is the worst kind in that it can replace about 60 per cent of the RNA in an infected cell against the one per cent that any other virus replaces.
SARS-CoV-2 rewires the alarm system that cells use to warn others about infection, The New Yorker quoted tenOever as saying.
In normal immune response, a cell sends out two kinds of signals - one transmitted through molecules called interferons and other carried by molecules called cytokines. While the first signal alerts neighboring cells to defend themselves against viral spread, the second signal summons the white blood cells, which don’t just eat invaders and infected cells, but also gather up their dismembered protein parts. These fragments are used to create virus-specific antibodies.
While most viruses that infect humans shut down both these signalling programmes, SARS-CoV-2 inhibits only the interferon response, says tenOever.
This imbalanced immune response causes the potentially deadly blood clots, strange swelling in children, and ultra-inflammatory “cytokine storms” that health experts have reported in Covid-19 patients. The results of their study were published in the biweekly journal Cell.
The Icahn researchers also found the immune systems in older victims were less adaptive, which make them more prone to the destruction caused by the virus.
SARS-CoV-2 first enters through the nose and throat when someone inhales virus-laden air droplets expelled by an infected person. The cells in the lining of the nose are rich in angiotensin-converting enzyme 2 (ACE2) that the virus requires to enter a cell. ACE2 is present throughout the body.
Once inside a cell, the virus hijacks the cell’s machinery and makes myriad copies of itself which then invade new cells. An infected person may show no symptoms or may develop a fever, dry cough, sore throat, loss of smell and taste, or head and body aches during the first week or so. But the patient may shed huge amounts of the virus during this time.
If the immune system doesn’t destroy SARS-CoV-2 during this initial phase, it can reach the windpipe to attack the lungs, where it can turn deadly. The virus is also known to affect other key organs like kidneys, heart and brain.