This year, antibody tests for COVID-19 have steadily evolved from simple, red light/green light assays, which could only check whether a person has been previously exposed to the coronavirus, into tools that deliver more detailed information into the body’s ability to protect itself.
When presented with an invading virus, the body’s immune system typically produces a wide number of different antibodies designed to tag different aspects of the pathogen, although only a few are actually able to defend cells. Knowing which ones are the most effective, and how many are needed for immunity, is essential knowledge as vaccines come to bear on the pandemic.
Now, Siemens Healthineers—one of the first to market with diagnostics that analyze the relative amount of antibodies present in a person’s blood sample, instead of giving just a yes-or-no result—has put forward a similarly quantitative test that measures the antibodies capable of neutralizing the coronavirus, and ultimately slowing the infection.
The company’s IgG antibody test is a new version of the diagnostic it launched over the summer. It has received a CE Mark for approval in Europe, and is currently under review at the FDA for a U.S. emergency authorization.
Siemens said this test will be able to gauge the level of immunity a vaccine can provide, and the company aims to make it available internationally for its automated Atellica, Advia Centaur and Dimension laboratory hardware.
“At the onset of the pandemic, the scientific community had to learn about COVID-19 and how our immune systems would respond,” said Deepak Nath, Siemens’ president of laboratory diagnostics. “We targeted the spike protein for our antibody tests, anticipating antibodies to this protein would eventually prove to be neutralizing."
“Adequate data is available now to confirm the spike protein antibodies are indeed neutralizing, especially those against the spike receptor-binding domain,” Nath added. “Healthcare providers can feel confident that our test will help them determine whether a patient's immune system is producing the right antibodies to stop or prevent COVID-19 infection.”
Nath was recently named one of Fierce Pharma’s most influential people in the fight against the coronavirus pandemic, for his and his team’s work to help set standards for COVID-19 antibody tests.
Researchers at Siemens have been working with the European Union’s Joint Research Centre and the U.S. Centers for Disease Control and Prevention to define the necessary concentrations of specific antibodies in the bloodstream, and help establish a clinical threshold for tests that could identify whether a person is immune to the coronavirus.
The FDA recently authorized its first commercial COVID-19 test for neutralizing antibodies, developed by GenScript and the Duke-National University of Singapore Medical School.
The test combines recombinant fragments of the coronavirus spike protein’s receptor binding domain with an enzyme derived from horseradish roots—making the efforts to measure virus-neutralizing antibodies more practical, compared to live samples of the coronavirus that would require specialized biocontainment laboratories.