COVID-19 antibody that protects against broad range of variants identified
Researchers have identified an antibody that is highly protective at low doses against a wide range of variants of the SARS-CoV-2 virus which causes the deadly COVID-19. The findings, posted as a pre-proof in the journal Immunity, could help develop new antibody-based therapies that are less likely to lose their potency as the virus mutates.
Current antibodies may not work against all variants: Author
The new antibody attaches to a part of the virus that differs little across the variants, meaning that it is unlikely for resistance to arise at this spot, the researchers said. "Current antibodies may work against some but not all variants," said study senior author Michael S Diamond, a professor at Washington University School of Medicine in St Louis, US.
Virus will likely continue to evolve: Author
"The virus will likely continue to evolve over time and space. Having broadly neutralizing, effective antibodies that work individually and can be paired to make new combinations will likely prevent resistance," Diamond said.
Many variants have acquired mutations in their spike genes
The SARS-CoV-2 virus uses a protein called spike to attach to and invade cells in the body's respiratory tract. Antibodies that prevent the spike protein from attaching to cells neutralize the virus and prevent disease. Many variants have acquired mutations in their spike genes that allow them to evade some antibodies generated against the original strain, undermining the effectiveness of antibody-based therapeutics.
Researchers immunized mice with key part of the spike protein
To find neutralizing antibodies that work against a wide range of variants, the researchers immunized mice with a key part of the spike protein called the receptor-binding domain (RBD). They then extracted antibody-producing cells and obtained 43 antibodies from them that recognize RBD. They screened 43 antibodies by measuring how well they prevented the original variant of SARS-CoV-2 from infecting cells in a dish.
Multiple antibodies passed both tests with varying degrees of potency
Nine of the most potent neutralizing antibodies were then tested in mice to see whether they could protect animals infected with the original virus from disease. Multiple antibodies passed both tests with varying degrees of potency, according to the researchers.
Two antibodies were tested against a panel of viral variants
They selected two antibodies that were most effective at protecting mice from disease and tested them against a panel of viral variants. The panel comprised viruses with spike proteins representing all four variants of concern - Alpha, Beta, Gamma, and Delta - two variants of interest (Kappa and Iota), and several unnamed variants that are being monitored as potential threats.
