Researchers at Washington University School of Medicine in St. Louis, USA have identified an antibody called SARS2-38, which is highly resistant to a variety of virus variants at low doses and is unlikely to be lost when the virus mutates Effectiveness. Related papers were published on the website of the top international immunology journal "Immunity" recently, marking a new step towards the development of antibody therapy.
Spike protein is the "siege hammer" for the COVID-19 virus to invade the city of human cells. Neutralizing antibodies can prevent the virus from infecting cells by binding to the spike protein of the COVID-19 virus. Many variants have mutations in the spike protein, which can evade neutralizing antibodies, thereby weakening the effectiveness of antibody therapy.
In order to find neutralizing antibodies that are effective against multiple mutations, the researchers first immunized mice with a key part of the spike protein called the receptor binding domain. Then, they extracted the antibody-producing cells and obtained 43 kinds of antibodies that recognize the receptor binding domain.
By measuring the effect of preventing the COVID-19 virus from infecting cells, the researchers screened these 43 antibodies. Then, the researchers tested the nine most effective neutralizing antibodies in mice to see if they could protect the mice from viral infections. Multiple antibodies passed these two tests, but their effectiveness varied.
The researchers selected the two most effective antibodies in protecting mice from viral infections and tested them with a set of virus variants. This group of virus variants includes the "worrying" COVID-19 virus variants Alpha, Beta, Gamma and Delta, as well as the "noticeable" COVID-19 virus variants Kapa and Yota, and also There are several potentially threatening mutant strains that are being monitored but not named.
The study found that an antibody called SARS2-38 can easily neutralize all mutant strains. In addition, the humanized version of SARS2-38 protects mice from diseases caused by two mutant strains: Kappa and a virus containing a spike protein from the beta variant. The researchers pointed out that the beta mutant strains are particularly notable for their inability to resist SARS2-38.
"This antibody has both high (which means it works well at low concentrations) and broad (which means it is effective for all variants) neutralization." Senior author of the paper, M.D. Michael S Diamond Said that this combination of characteristics is "unusual and ideal" for an antibody. In addition, antibodies can almost be attached to the same site on variant strains of different viruses, which means that the virus is unlikely to be resistant.
Next, researchers may consider combining this antibody with another antibody attached to other sites of the viral spike protein to create a combination therapy that is difficult for the virus to resist.
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