Antibody that can block COVID-19 virus 100% seen as strong drug candidate

The antibody, called STI-1499, can completely neutralised the COVID-19 virus infectivity at a very low antibody dose, say researchers. It may lead to an antibody cocktail product that would act as a "protective shield" against SARS-CoV-2 coronavirus infection, they added.

By: Longjam Dineshwori | | Updated: May 18, 2020 11:02 am

Antibody therapy has shown some positive results in COVID-19 treatment. @Shutterstock

Antibody therapy has been used for years to combat many diseases such as measles, Ebola, H1N1 flu, and polio. Researchers are also seeing it as a promising method of treatment for keeping the novel coronavirus at bay until a vaccine is developed. The therapy uses antibodies – proteins made by the immune system – to help the body fight diseases. Also Read - Which homemade face mask works best against the novel coronavirus? Here’s the verdict

US-based biopharmaceutical company Sorrento Therapeutics has announced that it has identified an antibody which can completely block SARS-CoV-2 infection of healthy cells. In preclinical laboratory experiments, the antibody, called STI-1499, completely neutralised the COVID-19 virus infectivity at a very low antibody dose. This indicates that STI-1499 is a potentially strong antibody drug candidate, the company said. Also Read - RNA experiments leading in COVID-19 vaccine race, but questions remain about their safety

“Our STI-1499 antibody shows exceptional therapeutic potential and could potentially save lives following receipt of necessary regulatory approvals,” Henry Ji, Chairman and CEO of Sorrento, said in a statement. Also Read - My quarantine days in Manipur: When you become an outsider in your own hometown

He added that the researchers at Sorrento are working hard to complete the steps necessary to get this product candidate approved and available to the public. The company aims to generate an antibody cocktail product that would act as a “protective shield” against SARS-CoV-2 coronavirus infection.

The company has been screening antibodies that can block the S1 protein’s interaction with human angiotensin-converting enzyme 2 (ACE2), the receptor used for viral entrance into human cells. Among these, the antibody, STI-1499, stood out for its ability to completely block SARS-CoV-2 infection of healthy cells in the experiments. Sorrento said STI-1499 will likely be the first antibody in the antibody cocktail (COVI-SHIELD) it is developing.

STI-1499 is also expected to be developed as a stand-alone therapy, (COVI-GUARD) because of the high potency it has exhibited in experiments to date.

Antibody therapy improves recovery of COVID-19 patients

As there is no vaccine or cure for COVID-19 disease yet, doctors around the country are experimenting with different approaches to treat patients infected with the virus. Meanwhile, blood plasma therapy has shown some positive results. Many patients, who were hospitalised in a critical condition for COVID-19, are reportedly showing signs of recovery after giving this treatment. In this therapy, antibody-rich blood plasma is harvested from recovered COVID-19 patients and transfused into other sick patients.

Also known as convalescent plasma therapy, this old technique was also used to treat patients during the SARS outbreak.

How Antibody Therapy Works

When a pathogen like the COVID-19 virus infect us, our immune system produces antibodies to help fight it off. Antibodies are proteins secreted by immune cells called B lymphocytes when they encounter an invader.

A person who has recovered from COVID-19 sickness, especially those whose blood is rich in antibodies for that pathogen, can donate the blood for plasma transfusion. The potential donor is examined before the blood serum is extracted and given to a sick person. The recovered person should be asymptomatic for at least 28 days to become a donor. In addition, he/she has to be declared as cured and the swab test must be negative.

Use of convalescent plasma therapy have shown positive results in some studies. Some critically ill patients who received doses of antibodies have improved and stopped relying on ventilators.

(With inputs from IANS)

Published : May 17, 2020 1:00 pm | Updated:May 18, 2020 11:02 am

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