SARS-CoV-2, which is causing a global health and economic crisis, is not the first coronavirus that humanity faces, although it is the one that has caused the greatest impact. Coronaviruses were discovered in the middle of the 20th century, and they cause respiratory diseases of different magnitudes. SARS-CoV, of which an outbreak occurred in the winter of 2002 to 2003, is one of them, and could be considered a first cousin of the SARS-CoV-2 that causes COVID-19, presenting many similarities to it, such as spike proteins used for infection in healthy cells in the body.
An ‘Achilles heel’
Herein lies the importance of new research published by the journal Science on April 7, in a context in which scientific efforts are focused on finding possible therapeutic avenues for COVID-19. In this case, the study consists of the recovery of an antibody from a survivor of the SARS epidemic outbreak in the early 2000s. This antibody has revealed a possible ‘Achilles heel’, a vulnerability, for the new coronavirus .
The study is the first to monitor the interaction of a human antibody with the new coronavirus at near-atomic-scale resolution.
Structural mapping revealed a specific region in which the antibody is able to bind to the virus, to ‘kill’ it; this region is almost identical in both coronaviruses, suggesting that the antibody could cause this vulnerability not only for SARS-CoV, but also for SARS-CoV-2. For more data, both viruses differ only by four protein building blocks called amino acids. This high degree of similarity implies that the binding region of the antibody has an important function that would be lost if it were significantly mutated. The antibody in question is called CR3022, and it was originally isolated in 2006 by the pharmaceutical company Crucell Holland BV in the Netherlands.
The Scripps Research analysis found that this ‘vulnerability’, or antibody-binding region, is relatively remote from the part of the virus that attaches itself to protein receptors on cells in our lungs. That suggests that, at least for SARS-CoV, CR3022 would neutralize the coronavirus’s ability to indirectly infect cells.
The fact that this binding site is conserved in SARS-CoV and SARS-CoV-2 also suggests that there may be other antibodies, yet to be discovered, that can effectively neutralize both viruses ; and, perhaps in the same way, also other possible coronaviruses that could lead to another pandemic.
Scripps Research’s Wilson Laboratory, which has published the study, is known for pioneering research on antibodies bound to viruses such as HIV and influenza: “Our ultimate goal here is to obtain structural information about antibodies and their binding sites, and use it to guide the design of the SARS-CoV-2 vaccine, just as our laboratory has done with influenza and HIV, “according to one of the authors, Nicholas Wu, associate postdoctoral researcher.
Referencias:
‘A highly conserved cryptic epitope in the receptor-binding domains of SARS-CoV-2 and SARS-CoV’ are Meng Yuan, Nicholas Wu, Xueyong Zhu, Chang-Chun Lee, and Ian Wilson, of Scripps Research; and Ray So, Huibin Lv, and Chris Mok of the University of Hong Kong. DOI: 10.1126/science.abb7269
