Researchers from China's Beijing Institute of Biotechnology have identified a potent new antibody from recovered COVID-19 patients. This antibody, named 4A8, exhibits strong neutralizing activity but binds to an unconventional region of the virus.
In late May 2020, Taiwanese scientists reported a monoclonal antibody that blocks SARS-CoV-2 entry into human cells, achieving 90% to 98% inhibition rates.
Building on this, a study published in Science on June 22, 2020, details antibody 4A8, isolated from the blood of over a dozen recovered patients. While it demonstrates robust neutralization, 4A8 uniquely targets a different epitope on the spike protein compared to most antibodies.
Vaccines work by introducing harmless pathogen versions, prompting the body to generate targeted antibodies that bind specific viral epitopes. For SARS-CoV-2, these typically focus on the spike (S) protein, which interacts with our cells' ACE2 receptors to initiate infection.
Unlike others, 4A8 binds to the opposite end of the spike protein, away from the ACE2 contact site. Structural analyses reveal it prevents the protein's necessary conformational changes for receptor binding, effectively neutralizing the virus without direct blockage.
The research team, having patented 4A8, aims to enhance its potency. This approach broadens attack sites on the virus, reducing mutation escape risks and improving treatments.
