Rapid test can detect antibodies against different variants of COVID-19

Coronaviruses have genetic corrective mechanisms to maintain their genomes and are susceptible to mutations that can alter virus replication, transmission, and recognition through the host’s immune response. In this context, the news of the discovery of a new type of SARS-CoV-2 virus in South Africa caused a global uproar.

There was already evidence of the variables beta and gamma They can avoid neutralization by monoclonal antibody (mAb) treatments and are more resistant to neutralization by polyclonal antibodies resulting from natural infection or immunization.

The two variants of concern beta and gamma, as well as deltas identified in India, have posed new challenges in efforts to contain the spread of the virus. And now the South African, Ómicron, has once again put the world of science under scrutiny in search of new answers to renewed doubts.

Now, biomedical engineers from Duke University in the United States, Developed a test to quickly and easily assess the effectiveness of a person’s neutralizing antibodies in fighting infection with multiple COVID-19 variants, such as Delta and the newly discovered Omicron variantAnd as posted in the magazine science advances.

We have developed a rapid test called CoVariant-SCAN, which detects neutralizing antibodies (nAbs) capable of blocking interactions between the ACE-2 receptor, the wild-type SARS-CoV-2 (WT) peak protein, and three other variants: B.1.1.7, B.1.351 and P.1. Using CoVariant-SCAN, we assessed neutralization/blocking of monoclonal antibodies and plasma from existing individuals vaccinated with COVID-19,” the authors of the work explain in detail. in the post from their conclusions.

In addition, this test can show clinicians the degree to which the patient is protected from novel variants and those currently circulating in the community or, conversely, identify monoclonal antibodies to treat the patient with the COVID-19 virus.

Cameron Wolf, assistant professor of medicine at Duke University School of Medicine, noted that “there is currently no rapid way to assess which variants, their presence in an individual, or the ability of antibodies should make a difference.”

And after acknowledging that “one continuing concern is that as more and more people are successfully vaccinated, a variant may emerge that drastically avoids the antibody inactivation caused by the vaccine”The researcher explained: “And if this fear is realized –If Ómicron turns out to be the worst case – how do we know fast enough?

“While developing a point-of-care test for antibodies and biomarkers for COVID-19, we realized that being able to detect the ability of antibodies to neutralize certain variants might be useful, so we built a test around that idea.” , completed Ashutosh Chilcotty, Alan L. Kaganoff Distinguished Professor and Professor of Biomedical Engineering at Duke University.

And he added: “It only took us a week or two to add the delta variable to our testing, and it can easily be expanded to include the Omicron variable as well. All we need is this type of spike protein, those many groups from all over the world — including our group at Duke — we work hard to produce.”

The researchers called their test the COVID-19 Spike-ACE2 Competitive Variable Antibody Neutralization Test, or CoVariant-SCAN for short, and the test technology is based on a brush-shaped polymer coating that acts like a species. desirable biomarkers from sticking to the test strip when wet.

The highly effective non-stick shield makes the test incredibly sensitive even at the lower levels of your targets. This method allows researchers to print different molecular traps in different regions of the slide to capture multiple biomarkers at the same time.

In this application, the researchers imprint on a chip of fluorescent human ACE2 proteins, which are cellular targets of the infamous viral spike protein. They also print specific spike proteins from each variant of COVID-19 at different specific sites. When tested, ACE2 proteins are ejected from the slide and trapped by the barbed proteins still attached to the slide, causing the slide to glow.

but In the presence of neutralizing antibodies, spike proteins are no longer able to bind to ACE2 proteins, making the chip less luminous, indicating antibody efficacy. By printing different variants of the COVID-19 protein on different parts of the slide, researchers can test the antibody’s effectiveness in preventing each variant from capturing a human cell target at the same time.

“In all of our tests, the results largely mimic what we’ve seen in the literature”“In this case, not finding anything new is a good sign, because it means that the test works just like the methods currently in use,” explained Jake Hegstad, a doctoral student working in the Chilcotty lab.

Antibody detection assays for SARS-CoV-2 are an important tool for assessing the normal or induced humoral response to a vaccine at the individual patient level and for epidemiological surveillance at the population level.

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