Covid-19: Researchers identify antibody 'highly protective' against SARS-CoV-2 variants

The antibody, SARS2-38, 'easily neutralised' all six SARS-CoV-2 variants it was tested against, including Beta, which is known for its resistance to antibodies.

Researchers at the Washington University School of Medicine, St. Louis, claim to have identified an antibody which, they say, is "highly protective" against various variants of the SARS-CoV-2 virus, when delivered in low doses, news agency PTI has reported.

For the study, the group immunised mice with the receptor-binding domain (RBD), a key part of a protein known as "spike." This protein is used by SARS-CoV-2 to attach itself to the respiratory tract of a human body, and to invade cells in it.

The team then proceeded to extract antibody-producing cells, and obtained from them 43 antibodies which recognise RBD. These antibodies were then screened on the basis of how well these prevent the original SARS-CoV-2 virus from infecting cells kept in a dish.

Separately, nine of the "most potent" antibodies were tested on mice to check if these could protect animals infected with the original SARS-CoV-2 strain. According to the researchers, multiple antibodies passed the test, with varying degrees of potency. Two of these, found to be the most effective at protecting the mice, were selected and tested on a range of variants which cause the viral disease.

The variants included all four variants of concern (VoC) -- Alpha, Beta, Gamma and Delta -- and Kappa and Iota, both of which are variants of interest (VoI).

Finally, the team found that one antibody, SARS2-38, "easily neutralised" all the six variants it was tested against, noting, in particular, the inability of the Beta variant to resist the antibody. This, they said, is "particularly remarkable" as the Beta variant is known for its resistance to antibodies.

Speaking on the exercise, Michael S Diamond, a professor at the School of Medicine said, "Current antibodies may work against some variants, but not all. Since the virus is likely to continue to evolve, having broadly neutralising, effecting antibodies which work individually, and can also be paired to form new combinations, will likely prevent any resistance from the virus."

The findings of the study were posted as a "pre-proof" in the journal Immunity. The results, according to the researchers, could help in the development of new antibody-based therapies likely to not lose potency as SARS-CoV-2 mutates.