The most effective gene
A common gene was found in antibodies to coronavirus
Maria Krivochenko, Naked Science
The spike protein is responsible for the penetration of the virus into the cell and serves as one of the main targets for vaccines. The SARS-CoV-2 virus protein uses its receptor-binding domain (RBD) to influence the ACE2 receptor and trigger the process of cellular infection. Antibodies targeting the domain can block it and thereby neutralize the virus.
The authors of a study published in the journal Science (Yuan et al., Structural basis of a shared antibody response to SARS-CoV-2) analyzed almost 300 such antibodies and found that the most effective of them are encoded by the IGHV3-53 gene. It occurs in 10% of the samples, unlike other genes of the IGHV group (affect the receptor-binding domain of the spike protein), which occurred on average with a frequency of 1.8%. The researchers also noted that antibodies with IGHV3-53 contain an unusually short version of the CDR H3 loop, usually responsible for binding to the antigen. However, they are much more effective against SARS-CoV-2 compared to other antibodies not encoded by IGHV3-53.
As previous experiments have shown, antibodies with IGHV3-53 are found in both healthy and infected people. Scientists suggest that increasing their concentration due to the vaccine will provide reliable and stable protection against coronavirus.
To understand how the gene works, the group used the method of X-ray crystallography. She received images of two antibodies attached to SARS-CoV-2. It turned out they use different genes to attack the virus. The results show that it can combine with various light chains (protein compounds that are part of antibodies) to block SARS-CoV-2.
IGHV3-53 antibodies attached to their target, the receptor-binding domain of the coronavirus spike protein.
"We were able to identify unique structural features of the antibodies encoded by IGHV3-53, which explain why they bind so well to SARS-CoV-2," says first author Meng Yuan.
Scientists drew attention to another property of antibodies – after infection, they practically did not change. Usually, when encountering a virus, the antibodies mutate to better fight the antigen. The more of these changes are needed, the more difficult it is to develop a vaccine.
"Coronaviruses have been around for hundreds of years, and it can be assumed that our immune system has evolved in such a way that we carry antibodies like these that are ready to immediately give a powerful rebuff," said Ian Wilson, Hansen professor of structural biology and head of the Department of Integrative Structural and Computational Biology Scripps Research.
Scientists cannot yet understand which molecular features are responsible for the effectiveness of antibodies. But the results of a new study can be a starting point for creating a vaccine. IGHV3-53 antibodies react quickly to the virus, which will simplify its development. In addition, scientists suggest that their analysis may be a marker of success in future trials.
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