MIT researchers have developed an easy-to-use test that may be able to predict an individual’s immune response to SARS-CoV-2. Credit: Courtesy of the researchers. Edited by MIT News.
Key points:
- A new at-home blood test may be able to predict an individual’s immune response to SARS-CoV-2.
- The test can be easily modified to detect immunity against any existing or future variant of SARS-CoV-2.
- MIT researchers are looking for a partner and FDA approval.
The question of the summer was: is it the flu, or a cold, or COVID-19? While there’s an at-home test for that, anyone who wants to measure their current immunity against COVID-19 is not so lucky.
Now, MIT researchers have developed an easy-to-use test that can answer that question. The test uses the same “lateral flow” technology as pregnancy tests and most rapid antigen tests for COVID-19.
MIT’s Hojun Li, Hadley Sikes and Sangeeta Bhatia teamed to develop a device that can detect the presence of antibodies that block the SARS-CoV-2 receptor binding domain (RBD) from binding to ACE2, the human receptor that the virus uses to infect cells.
The first step in the test is to mix human blood samples with viral RBD protein that has been labeled with tiny gold particles that can be visualized when bound to a paper strip. After allowing time for antibodies in the sample to interact with the viral protein, a few drops of the sample are placed on a test strip embedded with two test lines.
One of these lines attracts free viral RBD proteins, while the other attracts any RBD that has been captured by neutralizing antibodies. A strong signal from the second line indicates a high level of neutralizing antibodies in the sample. There is also a control line that detects free gold particles, confirming that the solution flowed across the entire strip.
The researchers tested their device with blood samples collected in December 2020 from about 60 people who had been infected with SARS-CoV-2 and 30 people who had not. They were able to detect neutralizing antibodies in the samples from people previously infected to the virus, with accuracy similar to that of existing laboratory tests. They also tested 30 serial samples from two people before they received an mRNA COVID-19 vaccine and at several time points after vaccination. The level of neutralizing antibodies in the vaccinated individuals peaked around seven weeks after the first dose, then began to slowly decline—supporting previous studies of SARS-CoV-2.
Importantly, the researchers say the test is designed so that different viral spike proteins can be swapped in, allowing it to be modified to detect immunity against any existing or future variant of SARS-CoV-2.
The team is hoping to partner with a diagnostics company that could manufacture large quantities of the tests and obtain FDA approval for their use.
Information provided by MIT.