SARS-CoV-2 on cell surface in culture
NIAID-RML
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Researchers from the Netherlands have found that the 47D11 human anti-S protein on the surface of the SARS-CoV virus neutralizes SARS-CoV-2 in cultures, preventing it from adhering to and penetrating into the cells. The article was submitted for review in Nature, her preprint is available at biorxiv.org.
SARS-CoV-2, which caused the current pandemic, is very similar in structure to SARS-CoV, the causative agent of severe acute respiratory syndrome (“SARS”), whose outbreak occurred in 2002-2003. As part of the fight against that epidemic, some potential anti-SARS-CoV agents were developed, however, their clinical trials failed: the number of infected decreased and became insufficient for such trials.
Now Berend-Jan Bosch from the University of Utrecht and Frank Grosveld from the Erasmus University of Rotterdam Medical Center tested the S-protein monoclonal antibodies on the surface of SARS-CoV, which they received about 15 years ago and since pores were stored in a frozen state, since the epidemic caused by that virus had already ended at that time.
Antibodies, in particular 47D11, were obtained from hybridomas of transgenic mice and introduced into the cultures of VeroE6 green monkey cells and HEK-293T human kidney cells, previously infected with vesicular stomatitis viruses with S-proteins from SARS-CoV or SARS-CoV-2 on the surface. An enzyme-linked immunosorbent assay checked whether 47D11 was attached to the S protein of viruses.
–Neutralization of virus particles mimicking SARS-CoV and SARS-CoV-2, antibody 47D11
Chunyan Wang et al. / biorXiv, 2020
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– The antibody neutralized the viruses (that is, they stopped spreading over the culture) in half the cases when it was administered at a concentration of 0.19 and 0.57 mg / ml, respectively. An enzyme-linked immunosorbent assay revealed which part of the S protein is attached to 47D11. This turned out to be a rather conservative S1B site by which the viral protein binds to the ACE2 protein (ACE-2, angiotensin converting enzyme 2) on the human cell.
47D11 is the first human antibody capable of preventing the penetration of SARS-CoV and SARS-CoV-2 into the cell and thus stop the infection. In theory, it can not only protect those who have not yet been infected, but also help patients get rid of the virus.
Researchers are currently looking for a pharmaceutical company that will be ready to conduct clinical trials of 47D11. They will take at least a few months. It is likely that the antibody will be able to be used for diagnostic purposes. In theory, you can create test systems with it that allow you to identify the presence of a new coronavirus in a person without leaving your home. However, the vaccine, according to the authors, will have to wait longer, and their antibody will not become its component (usually vaccines contain virus proteins or larger fragments of viral particles, and not antibodies against them).
It is possible to neutralize not the proteins of the virus, but the proteins of the cells to which it attaches. In this light, it is particularly encouraging that, in addition to the ACE2 protein on the surface of human cells, SARS-CoV-2 also interacts with the CD147 protein. An antibody to this protein already exists, since it also serves as a target for malarial plasmodium, a long-known causative agent of another disease. Tests of its effectiveness and safety to combat COVID-19 have been launched.
Svetlana Yastrebova
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