Researchers identify Covid antibody that protects against wide range of variants

Researchers have identified a COVID antibody that provides protection against a wide range of COVID-19 variants.

The Covid antibody works by attaching to a part of the virus that differs a little across the variants. As per researchers, this means that it is unlikely for resistance to arise at this spot.

The identified antibody is highly protective at low doses against a wide range of variants of the SARS-CoV-2 virus that causes Covid-19. The findings were posted in the journal Immunity. 

Significance

•The findings could help develop new antibody-based therapies that are less likely to lose their potency as the virus mutates.

•As per the study's senior author Michael S Diamond, who is a professor at Washington University School of Medicine in St Louis, US, "current antibodies may work against some but not all variants."

•Professor Diamond said that the virus is likely to evolve over time and space and having broadly neutralising, effective antibodies that work individually and can be paired to make new combinations will likely prevent resistance.

How does COVID antibody work?

•The SARS-CoV-2 virus uses a spike protein to attach and invade cells in a person's respiratory tract. The antibodies prevent the spike protein from attaching to cells and thus, neutralise the virus and prevent the infection. 

•However, many variants of COVID-19 have acquired mutations in their spike genes as well, which allow them to evade some antibodies generated against the original strain of the virus, which undermines the effectiveness of antibody-based therapeutics.

•The researchers had immunised mice with a key part of the spike protein known as the receptor-binding domain (RBD) to find neutralising antibodies that work against a wide range of variants.

•The researchers then extracted antibody-producing cells and got 43 antibodies from them that recognise receptor-binding domain (RBD).

•They then screened all the 43 antibodies by measuring how well they prevented the original COVID-19 variant, which emerged in 2019, from infecting cells in a dish.

•Nine among the most potent neutralising antibodies were tested in mice to see whether they could protect animals infected with the original strain of the virus.

•As per researchers, multiple antibodies passed both tests with varying degrees of potency.

•They then selected two antibodies that were most effective at protecting mice from the virus and tested them against a panel of COVID-19 variants.

•The panel comprised viruses with spike proteins that represented all four variants of concern Alpha, Beta, Gamma and Delta and two variants of interest -Kappa and Iota and several unnamed variants that are being monitored as potential threats.