This neutralizing antibody attacks all known variants of the coronavirus

The arrival of every variant of SARS-CoV-2 threatens the effectiveness of vaccines and antibody therapies available. Omicron is so different from the others that it has put failed most of them prescribed before arrival. Scientists hope to develop an antibody that could neutralize all variants of SARS-CoV-2. The one presented recently in Science Immunology is not the first nor the last, but it has an asset that makes it worthy of interest.

A neutralizing antibody against all variants

SP1-77, that’s its name, was obtained thanks to laboratory mouse genetically engineered to produce humanized antibodies — mouse antibodies that have parts of them that are human. To isolate those who reacted to SARS-CoV-2, the scientists brought them into contact with the original Wuhan strain. Of all the antibodies that reacted, only SP1-77 was able to neutralize the Wuhan strain and all other known variants including those of the Omicron family.

What makes SP1-77 so special? Scientists have studied its structure using cryomicroscopy electronics, a technique that allows antibodies to be visualized down to the amino acid. Like most neutralizing antibodies, SP1-77 binds to the RBD, the part of the coronavirus that interacts with the cell’s receptor. But it neutralizes the virus in an unprecedented way. SP1-77 does not prevent recognition between the RBD and ACE2 but blocks the next step, the merger between the membrane of the virus and that of the cell of the two membranes, essential for the virus to infect its host cell.

Furthermore ” SP1-77 is fixed on a place of the protein S which has not been mutated in any variant of SARS-coV-2 so far, thus neutralizing the variants thanks to a new mechanism », explains Tom Kirchhausen from Boston Children’s Hospital.

This study is above all a proof of concept that the mice used by the scientists are able to produce neutralizing humanized antibodies against SARS-CoV-2. If SP1-77 shows interesting abilities in vitrothere is no reason to conclude that it is a serious candidate for being a new therapeutic antibody useful for treating the Covid-19.