Researchers at the Garvan Institute of Medical Research in Australia have developed a new generation of antibodies to treat COVID-19. So far, the antibodies have been shown to neutralize several of the viral variants behind COVID-19, and the researchers hope that they will form an effective treatment for at-risk patients. Previously developed antibody treatments for COVID-19 have been rendered largely useless as the virus has mutated. Such antibodies have focused on binding to the most obvious site on the viral spike protein, the ACE2 receptor binding site, but their efficacy in destroying the virus has waned with new viral variants. However, these new antibodies bind to a different site on the spike protein that is partially hidden, and appear to essentially rip the spike protein apart, prompting the researchers to surmise that the virus will find it hard to develop resistance.
SARS-CoV-2 continues to proliferate around the world. While vaccines have provided many of us with protection against severe disease, they do not offer the same level of protection for everyone. For instance, severely immunocompromised patients may not receive much benefit from current COVID-19 vaccines, and will likely require additional treatment if they contract the disease.
Developing new treatments for COVID-19 will greatly benefit such patients, but SARS-CoV-2 is a formidable adversary, with new variants popping up around the world. Unfortunately, previous iterations of antibody treatments for COVID-19 have been rendered largely ineffective by these mutations.
“Almost all commercially available antibodies for COVID-19 don’t work well anymore,” said Jake Henry, a researcher involved in the study. “Most are class 1 or 2, which refers to the fact that they bind to the most obvious spot on the spike protein – the ACE2 receptor binding site. They have downsides, including failure against new variants as they evolve. We’re delighted our research could lead to new antiviral therapy providing reliable ‘passive immunity’ to at-risk individuals.”
The new ‘class 6’ antibodies bind to a different part of the spike protein and can lead to its destruction. “This is a new mechanism of action we’re seeing with these class 6 antibodies,” said Daniel Christ, another researcher involved in the study. “Our hypothesis is that they’re so effective because the area we’re targeting is close to the center of the spike’s structure. When the antibody attaches there, it distorts the spike and rips it apart. It would be very difficult for the virus to adapt to that.”
Study in journal Nature Communications: Broadly neutralizing SARS-CoV-2 antibodies through epitope-based selection from convalescent patients
