BOSTON, August 10: Researchers in the United States have developed an easy-to-use test that can predict how well people are immune to COVID-19, whether through vaccination, infection or a combination of both.
Easy access to this type of testing could help people determine what kind of precautions to take against COVID-19 infection, such as an extra booster shot, the researchers said.
Described in the journal Cell Reports Methods, the test measures the level of neutralizing antibodies — responsible for defending cells against the virus — that target SARS-CoV-2 in a blood sample.
“Among the general population, a lot of people probably want to know how protected they are,” said Hojun Li from the Koch Institute for Integrative Cancer Research at the Massachusetts Institute of Technology (MIT), USA.
“But I think where this test could make the biggest difference is for anyone receiving chemotherapy, anyone taking immunosuppressive drugs for rheumatological disorders or autoimmune diseases, and for anyone older. or who doesn’t have good immune responses in general,” Li said.
These people might need to be boosted earlier or given more doses to get adequate protection, the researchers said.
The test is designed so that different viral spike proteins – which help the virus enter and infect cells – can be swapped.
This makes it possible to detect immunity against any existing or future variant of SARS-CoV-2, the researchers said.
The researchers have filed for a patent on the technology and now hope to partner with a diagnostics company that could manufacture the devices and seek approval from the US Food and Drug Administration (FDA).
Currently, the gold standard approach to measuring immunity is to mix a blood sample with live virus and measure the number of cells in the sample that are killed by the virus.
This procedure is too dangerous to perform in most laboratories, so the most commonly used approaches involve non-infectious modified “pseudovirus” particles.
However, these approaches still require trained personnel working in a laboratory with specialized equipment, so they are not practical for obtaining immediate results. Li was inspired by home pregnancy tests, which are based on a type of test called a lateral flow test.
Lateral flow tests generally consist of strips of paper embedded with test lines that bind to a particular target molecule if present in a sample.
This technology is also the basis of most rapid home tests for COVID-19.
Li and his collaborators have developed a device capable of detecting the presence of antibodies that prevent the SARS-CoV-2 receptor binding domain (RBD) from binding to ACE2, the human receptor that the virus uses to infect humans. cells.
The first step in the test involves mixing human blood samples with a viral RBD protein that has been tagged with tiny gold particles that can be visualized when bound to a strip of paper.
After the antibodies in the sample have been allowed time to interact with the viral protein, a few drops of the sample are placed on a test strip integrated with two test lines.
One of these lineages attracts free viral RBD proteins, while the other attracts any RBD that has been captured by neutralizing antibodies, the researchers said.
A strong signal from the second line indicates a high level of neutralizing antibodies in the sample, they said. (PTI)