A team of researchers has identified a highly protective antibody that is effective at low doses against a wide range of viral COVID-19 variants.
Moreover, the 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 findings, published in the journal Immunity, could be a step toward developing new antibody-based therapies that are less likely to lose their potency as the virus mutates.
“Current antibodies may work against some but not all variants,” said researcher Michael S. Diamond from the Washington University in St. Louis in the US.
“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 added.
To find neutralising antibodies that work against a wide range of variants, the researchers began by immunising mice with a vital part of the spike protein known as the receptor-binding domain.
Then, they extracted antibody-producing cells and obtained 43 antibodies from them that recognise the receptor-binding domain.
The researchers screened the 43 antibodies by measuring how well they prevented the original variant of SARS-CoV-2 from infecting cells in a dish.
Nine of the most potent neutralising antibodies were then tested in mice to see whether they could protect animals infected with the original SARS-CoV-2 from disease. Multiple antibodies passed both tests, with varying degrees of potency.
The researchers selected the two of the most effective antibodies 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.
One antibody, SARS2-38, easily neutralised all the variants. Moreover, a humanised version of SARS2-38 protected mice against disease caused by two variants—kappa and a virus containing the spike protein from the beta variant.
The researchers noted that the beta variant is notoriously resistant to antibodies, so its inability to resist SARS2-38 is particularly remarkable.
The above article has been published from a wire agency with minimal modifications to the headline and text.