Antibody testing for COVID-19 prepares for its closeup in bid to ease pandemic restrictions

As states in the U.S. move past the initial push for tests to identify active COVID-19 infections, antibody tests are ramping up quickly to aid in disease surveillance and return-to-work screenings. The rush has spurred an explosion in serology tests, many hastily developed and of questionable value. However, as the pandemic enters its third month, some companies are offering high-accuracy tests with validated results.

San Diego-based Abreos Biosciences Inc. is looking to create a multiplex test that goes beyond the simple yes/no COVID-19 antibody results and measures the “specific flavors” of antibodies to provide a more complete picture of the antibodies in a person’s blood.

“What we do is make peptides that are what technically we call antigen mimetics. So we’re able to identify peptides that copy the biochemical shape of the target of the antibodies, in this case the virus, but on a much smaller scale than is typically done,” Bradley Messmer, Abreos’ CEO, told BioWorld. “And we go in and really home in on the precise epitope … that each antibody is sticking, and then we make a biochemical copy of that that can be used to detect those antibodies.”

Last week, the company – which primarily focuses on therapeutic monoclonal antibodies – submitted a grant to the National Institute of Allergy and Infectious Diseases for funding to support its work on a COVID-19 antibody test.

Abreos is initially focused on the IgG antibody, but is considering doing both IgG and IgM. “The differences between IgM, IgG and IgA are at the stalk of the antibody,” Messmer said. By measuring the binding side of the antibody, “when we define one of our peptides, it will work for the IgM, IgG or IgA version of that antibody, just with a different secondary detector.”

The technology could potentially lead to better understanding of who is protected against future infection and who is not.

“Once you see the spectrum of antibodies in different people, you can then say, OK, did anybody not have protection and does that match up with missing a certain antibody flavor or having too much of the other one,” Messmer said.

“This virus is new to humans, so we just don’t know,” he added. “But we know there’s a lot that could go wrong with a simple yes/no answer.”

Recent literature lends weight to Abreos’ approach. A study in the journal Cell suggests that the S1 gene, one of several antigenic epitopes on the SARS-CoV-2 spike protein, may play a role in interactions with receptor and inducing neutralizing antibodies to COVID-19.


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