Antibody ‘cocktails’ effective against SARS-CoV-2 variants

Antibody ‘cocktails’ effective against SARS-CoV-2 variants

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In laboratory tests, a team of researchers has analyzed the efficacy of a range of COVID-19 antibody-based therapeutics against the latest variants of SARS-CoV-2.

The researchers noted that some combinations of monoclonal antibody therapeutics were less effective against these new variants.

However, they also found that other updated combinations, or cocktails, of monoclonal antibodies — which target areas of the virus that change less frequently — showed promise in neutralizing the latest virus variants.

The research, published in the journal Nature Medicine, suggests directions for the development of future therapeutics that may be more resistant to mutations of SARS-CoV-2.

Researching SARS-CoV-2 therapeutics

A central focus of scientific research in response to the COVID-19 pandemic has been the development of vaccines.

However, scientists have also been looking at other therapeutics that may be effective in reducing transmission of the virus or decreasing the severity of its symptoms.

One such technology is monoclonal antibodies. According to the Food and Drug Administration (FDA), monoclonal antibodies are developed in a laboratory and designed to copy the function of a person’s antibodies that they produce in response to an infection, which in this case is SARS-CoV-2.

In the development of therapeutics, scientists have also used antibodies taken from people who have contracted the virus.

However, many of these technologies are based around early variants of SARS-CoV-2. As the virus has been spreading, it has developed mutations, which in some cases can make the virus more infectious.

Laboratory tests

In the present study, the researchers wanted to see the effectiveness of COVID-19 therapeutics on the variants of SARS-CoV-2 that have become more infectious after developing mutations.

They tested these new variants in a laboratory context to see how effective different therapeutics are at neutralizing the virus.

SARS-CoV-2 makes use of a spike protein to infect the cells of a host organism. In many of the monoclonal antibody therapeutics that researchers have developed, they have selected the spike protein as a good target.

However, it is also this spike protein that has been the site of mutations in the most transmissible new variants of the virus.

Developing an antibody cocktail

The researchers found that many of the therapeutics that have been developed in response to SARS-CoV-2 showed “moderate to substantially diminished neutralizing potency.”

However, they also found that two highly neutralizing monoclonal antibody cocktails showed only slightly reduced effectiveness against the variants.

Researchers at Vanderbilt University Medical Center in Nashville, TN, in collaboration with the University of Texas, the Washington University School of Medicine in St. Louis, MO, and the Swiss firm Vir Biotechnology developed the cocktails.

According to Prof. James Crowe, Jr., director of the Vanderbilt Vaccine Center (VVC), Ann Scott Carell Professor in the Departments of Pediatrics and Pathology, Microbiology, and Immunology at Vanderbilt, and co-author of the paper, “this study highlights the importance of rationally designed antibody cocktails like those we developed.”

Prof. Crowe said: “We chose two antibodies to create a mixture that specifically would resist escape by SARS-CoV-2. Fortunately, this work and several other papers recently published show that the protection mediated by the antibodies we discovered that are now in six different phase 3 clinical trials should extend to all current variants of concern.”

For Dr. Robert Carnahan, associate VVC director and associate professor of pediatrics, “these findings, that the antibodies we are developing inhibit the new SARS-CoV-2 variants well, are made even more important by the fact that some previously approved monoclonal antibody treatments look very unlikely to protect against these variants.”

“Using our variant-resistant antibody cocktails likely will provide an important new tool for controlling the COVID-19 pandemic.”

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