New test to detect neutralizing antibodies to COVID-19 - may reflect immunity

[Mary]

A small amount of neutralizing antibodies may be sufficient to confer immunity to COVID-19 - A new test has been developed by GenScript to detect these neutralizing antibodies:

Forbes: A New Test May Show Whether Your Immune System Can Neutralize The Coronavirus

When a virus infects our body, our immune system kicks into action to combat it in a number of ways. One part of that immune response involves antibodies, the tiny proteins which recognize a virus and stick to it. But not all antibodies are made equal.

“When you have a virus, you generate all these antibodies, but only a small fraction bind to the virus in a way that prevents it from infecting a cell,” GenScript’s Eric Wang explains. “Those are the neutralizing antibodies.”

Neutralizing antibodies make up less than 1% of the total antibodies measured by current commercial tests, and Wang says they’re being missed. That means we could be underestimating just how many people are already protected against reinfection with the virus.

Neutralizing antibodies are not sufficient in all cases. But based on the body’s response to other viruses, neutralizing antibodies are a good indicator of protective immunity in most patients who have recovered from a disease.

“All the antibody tests at the moment look at total antibodies, and these can reduce significantly just a few months after a patient recovers from Covid,” says Wang. “But as long as you have a small amount of neutralizing antibody, the patient may still be immune to the virus.”

Announcement by GenScript: GenScript Announces Publication of Clinical Data On New Method for Detecting COVID-19 Neutralizing Antibodies In Nature Biotechnology

Nature (published July 23, 2020):
A SARS-CoV-2 surrogate virus neutralization test based on antibody-mediated blockage of ACE2–spike protein–protein interaction