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Scientists discover another antibody that may block coronavirus in a SARS survivoR

An antibody first identified in a Severe Acute Respiratory Syndrome (SARS) survivor may stop the novel coronavirus in its tracks.

The antibody, called S309, targets the ‘spike proteins’ found on the outside of the virus that are used to invade our cells.

Lab tests showed S309 sticks to the proteins, effectively neutralizing them, according to researchers at the University of Washington School of Medicine in Seattle.

It comes as scientists at a California biotech company claim to have found an antibody that completely blocks the virus. 

With only a few treatments – and only authorized for emergency use – for the potentially fatal disease, the two new developments offer hope of a therapy or even a vaccine. 

Scientists discovered an antibody that inhibits the family of coronaviruses, including the novel virus (pictured) and SARS, in the blood sample of a SARS survivor

The antibody, called S309, disables the 'spike proteins' that the coronavirus uses to infect human cells. Pictured:  Tel Aviv University researchers study the novel coronavirus

The antibody, called S309, disables the ‘spike proteins’ that the coronavirus uses to infect human cells. Pictured:  Tel Aviv University researchers study the novel coronavirus 

The antibody is now on a fast-track development and testing path at San Francisco-based Vir Biotechnology.

If successful, it paves the way for using S309 – alone or in a cocktail – as a vaccine for high-risk groups or a drug to combat severe life-threatening symptoms.  

‘We still need to show that this antibody is protective in living systems, which has not yet been done,’ said Dr David Veesler, an assistant professor of biochemistry at the University of Washington School of Medicine, in a press release.

‘Right now there are no approved tools or licensed therapeutics proven to fight against the coronavirus that causes COVID-19,’ he added. 

What make this new antibody different is it was discovered in someone infected with a different coronavirus, SARS, in 2003 – 17 years ago.

‘This is what allowed us to move so fast compared to other groups,’ Veesler said.

For the study, published in the journal Nature, the team identified several antibodies of interest from a blood sample of the SARS survivor in ‘memory B cells’ that form following an infectious illness.  

They usually remember a pathogen the body has gotten rid of in the past, sometimes for a lifetime. 

This triggers the launch of an antibody defense against a re-infection.

Experiments found that S309 was particularly effective at targeting and disabling the spike proteins.

It was able to destroy the virus, known as SARS CoV-2, by engaging with a section of the spike protein near the attachment site to the host cell.

Tests showed the antibody recognizes a binding site that is seen across many coronaviruses – not just SARS and COVID-19. 

Combining S309 with other, weaker antibodies found in the SARS patient boosted the destruction of coronavirus.

This multiple cocktail may prevent the virus from mutating into a strain that the single-ingredient is defenseless at stopping. 

It comes on the heels of Sorrento Therapeutics, based in San Diego, claiming its antibody, called STI-1499, stopped the virus from entering 100 percent of healthy human cells in petri dish experiments. 

In a press release, the company says it has the ability to  produce up to 200,000 doses of the antibody per month.

The company has filed for emergency approval from the US Food and Drug Administration and is currently waiting.