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Utrecht – Dutch researchers have found a human antibody that can neutralize the two SARS corona viruses. In the Nature Communications (2020; DOI: 10.1038 / s41467-020-16256-y) presented results open the perspective on a new treatment or also the prevention of SARS-CoV-2.
People survive viral infections because their immune systems produce neutralizing antibodies against the pathogens. Antibody formation only starts after 1 to 2 weeks. In certain diseases, including COVID-19, it may be too late because the patient has previously died from the consequences of the infection.
The administration of antibodies is the basis of immunotherapy, which was proposed by Emil von Behring a century ago and is currently being tested on patients with COVID-19. Serum therapy, however, assumes that some patients have already survived the infection and that their immune system has formed sufficient antibodies.
This is not always the case and treatment may be delayed for new pathogens such as SARS-CoV-2 for the first patients. The treatment is also organizationally complex and not without risks, since in addition to the antibodies, other serum components that can harm the patient are usually transferred (serum disease).
Treatment with monoclonal antibodies would be more ideal, but even more difficult to implement in practice. These can now be produced in cell cultures. Several antibody preparations have already been developed for the treatment of Ebola fever, two of which, namely MAb114 and REGN-EB3, have proven to be more effective in a randomized study (NEJM 2019; 381: 2293-303) than the viral drug remdesivir, the currently the most promising active ingredient in COVID-19.
After the epidemic with the first SARS virus (2002/3), a team led by Berend-Jan Bosch from the University of Utrecht looked for antibodies that could prevent the viruses from entering the cells. The researchers have increased 51 different antibodies against SARS-CoV-1 in cell cultures in recent years. These were chimeric antibodies with parts of muses and people.
In the past few weeks, the researchers have examined whether these antibodies also neutralize SARS-CoV-2. Cross immunity was observed in 4 antibodies. One of these antibodies (47D11) was reformatted so that it only has human parts.
Initial laboratory experiments show that 47D11 is able to prevent SARS-CoV-2 infection of cells. It is not possible to predict whether 47D11 would also be effective in patients with COVID-19. Experience with Ebola shows that a mixture of several antibodies is usually required to stop the virus (and to prevent resistance). Since the antibody has only human parts, it could be well tolerated.
In principle, the antibody could be produced in large quantities in cell cultures. Before clinical trials can begin, however, extensive testing on laboratory animals may be required. The antibody could be used for both treatment and prevention. It could also be effective against future coronaviruses if they infect the cells via the same receptor as SARS-CoV-1 and -2. © rme / aerzteblatt.de
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