The Dutch biologists discovered the first antibody to neutralize the new coronavirus. But it's a long way from the cure.
. A group of researchers from the Netherlands published on biorxiv.org a preprint stating that the first monoclonal antibody blocking the coronaviruses SARS-CoV-2 and SARS-CoV was found. The discovery can be used to develop a drug against COVID-19.
Biologists from the Erasmus Medical Center (a structural unit of Erasmus University in Rotterdam) and Utrecht University have developed antibodies to combat the coronavirus that caused the COVID-19 epidemic. According to their claims, they found a monoclonal antibody that neutralizes both SARS-CoV-2 and SARS-CoV (SARS-Pneumonia Virus 2002). For this purpose, they used antibodies obtained in previous years to fight other coronavirus species, consistently testing them for their affinity for the new virus. An article by a group of 10 specialists is still under review in Nature magazine and is available as a preprint on biorxiv.org.
According to leading author Frank Grosveld in an interview with the Erasmusmagazine.nl University website, fifteen years ago he began researching the possibility of growing antibodies for humans in laboratory mice. The results were encouraging, so that a research and production company (Harbor Antibodies BV) was established on the basis of the Erasmus University Medical Center (Erasmus MC) and several other institutes. In particular, it was engaged in the production of antibodies for tumor treatment. During several outbreaks of coronavirus infections, it also developed antibodies for them.
Coronavirus S proteine attaching to cell receptor The S-protein of the coronavirus is attached to the cell receptor. Picture: National Institute of Allergy and Infectious Diseases, National Institutes of Health.
Antibodies that neutralize coronaviruses usually react to their spiky proteins (tridimensional glycoproteins, or S-proteins that are visible as characteristic coronaviruses in all virus images). With S-proteins, viruses "attach" to the cell's transmembrane receptors; in this case, the target is called ACE-2, or "angiotensin converting enzyme 2", and the mechanism of "attaching" to it in the new coronavirus is identical to that causing SARS (SARS epidemic of 2002). The chip proteins of both viruses, SARS-CoV-2 and SARS-CoV, are also structurally similar and very similar (77.5% similar) in their amino acid sequences. Based on the results of this research cycle, the laboratory has at its disposal a collection of 51 species containing the corresponding antibodies of cell lines ("hybrids"), which reacted to the previous version of the coronavirus dangerous to humans, i.e. SARS-CoV. Following the outbreak of a new epidemic, all these samples were resuscitated and studied to respond to the new virus. Four of the ELISA antibodies reacted to the new type of virus, and one of them, labeled 47D11, was found to be able to inhibit both clones, acting in the same way on the SARS-CoV and SARS-CoV-2 virus spiked protein. This discovery, backed up by 20 pages of additional material, formed the basis of an article now being discussed in Nature. According to general ethical principles, before the first round of review, researchers and their school are not allowed to make a statement to the press, although it is certainly not forbidden to talk about their developments in an interview format on the university page. Only after the adoption of the article for publication one should expect corresponding releases, which will be much wider.
This is not a vaccine, but a drug with the potential to stop the disease. A vaccine usually contains a protein that is somehow associated with a virus (a weakened strain or inactivated virus), which, once in the body, leads to the birth of "memory cells" or B-lymphocytes that generate the corresponding antibodies. In contrast, the drug itself supplies antibodies (in this case immunoglobulin type IgG1) to neutralize the virus, and can maintain an acceptable level of protection for some time, such as days or weeks, until recovery. According to F. Grossfeld, the development of the vaccine would take about two years, while a drug using open antibodies could appear earlier.
Antibody and spike protein binding Immunoglobulin 47D11 (antibody; illuminated with DAPI fluorescent dye) binds in GFP-labelled cells (with green fluorescent protein) to the spiked protein of two coronaviruses. A third virus, MERS, on which the antibody is not known to act, is used for negative control (placebo principle). From F.Grosveld et al. What did you manage to do in the end, when the cure is available, and what will be written in the news? In the language of the clinical trial protocol, the results of Dutch biologists are stage zero.