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Austin / Texas – U.S. researchers genetically engineered the Spike (S) protein that binds SARS-CoV-2 to epithelial cells and analyzed its 3D structure. In Science (2020; DOI: 10.1126 / science.abb2507) they report that antibodies against the SARS virus do not work against SARS-CoV-2 and therefore a separate vaccine will be required, for the development of which the current results form an important basis.
The team led by Jason McLellan from the University of Austin in Texas specializes in the research of coronaviruses such as SARS-CoV and MERS-CoV. After the Chinese virologists published the gene sequence for the new SARS-CoV-2 coronavirus on the Internet, the US researchers used the blueprint to produce the S protein that coronaviruses use to attach to epithelial cells by genetic engineering.
They were limited to a section of the S protein that protrudes outwards from the virus envelope. The focus of interest was the site of the S protein, which binds to the ACE2 receptor on the surface of epithelial cells.
Using cryo-electron microscopy, the researchers were able to reconstruct the 3D structure of the S protein. McLellan writes in the report that the binding to the ACE2 receptor is 10 to 20 times stronger. This could explain why SARS-CoV-2 is easier to transmit than the 1st SARS-CoV that triggered the 2002/3 epidemic.
The researchers initially suspected that antibodies isolated from SARS survivors also neutralize the new SARS-CoV-2. In this case, it would in principle be possible to produce an antibody preparation within a short time. The vaccines developed against the SARS-CoV (which were never used) could also have a protective effect against SARS-CoV-2.
However, none of the 3 SARS-CoV antibodies examined were able to neutralize SARS-CoV-2 in the laboratory experiments. The hope that the already developed vaccines protect against COVID-19, the disease caused by SARS-CoV-2, is fading.
With the rapid production of the S protein, however, the US researchers have created an important prerequisite for the development of a vaccine. If this vaccine produced neutralizing antibodies against SARS-CoV-2, it could protect against infection. © warmth / aerzteblatt.de
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