Biotech IDs Potent Covid-19 Antibodies

Scanning electron microscope image of SARS-Cov-2 virus, in orange, emerging from cells (NIAID, Flickr)

2 July 2020. A company discovering therapeutic antibodies identified antibodies considered particularly effective in neutralizing SARS-CoV-2 viruses causing Covid-19 infections. Affinity Biosciences Pty Ltd, a biotechnology enterprise in Melbourne, Australia discovered the neutralizing antibodies with Peter Doherty Institute for Infection and Immunity, affiliated with University of Melbourne.

Affinity Biosciences’ main work is discovering cancer treatments that invoke the immune system. The company’s technology, called retained display, operates where peptides, short chains of amino acids broken up from proteins, meet the surface of cells. Peptides are taken up by protein molecules called the major histocompatibility complex, which, working together, act as receptors for T-cells, white blood cells in the immune system. This combination of peptides and major histocompatibility complex sends out signals to T-cells indicating the cell contains altered proteins, as found in cancer, or infections, alerting T-cells to attack the cell.

Antibodies are structured and function similarly to T-cell receptors, and form an antigen where T-cells can bind. Affinity Biosciences says, however, antibodies that bind to peptide/major histocompatibility complexes are extremely rare, since antibodies need to find the precise counterpart amino acids in the peptide for the binding to occur. The company says its technology has libraries of 100 billion specialized antibodies and a discovery process to identify rare antibodies meeting these specialized binding properties.

For the SARS-CoV-2 virus, Affinity Biosciences says its retained display technology seeks out antibodies that neutralize the characteristic proteins on the virus’s spike that penetrate and infect human cells. In tests with the Peter Doherty Institute, the company says the discovered antibodies show a high affinity for SARS-CoV-2 spike proteins, and successfully neutralized the proteins, even in low concentrations.

“Our antibodies latch onto the virus spike protein and block its activity,” says Affinity’s CEO Peter Smith in a company statement. “These antibodies may be protective in humans by preventing the virus from gaining a foothold in healthy people exposed to the virus, and may be useful in arresting the progress of the virus in an infected person by blocking its ability to infect new cells and replicate.”

Affinity Biosciences says its SARS-CoV-2 antibodies are being assessed by the La Jolla Institute for Immunology in California, funded by the COVID-19 Therapeutics Accelerator. Last month, Affinity received additional funding for its SARS-CoV-2 antibodies from the Australian Medical Research Futures Fund, as part of a consortium to identify antibody therapies for Covid-19 infections.

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• Covid-19 Antibody Cocktail to Begin Clinical Trial
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• Industry, Univ. Labs Partner on Covid-19 Therapy

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