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Utrecht – Dutch researchers have found a human antibody that can neutralize the two SARS corona viruses. The in Nature’s Communications (2020; DOI: 10.1038 / s41467-020-16256-y) presented results that open the prospect of a new treatment or also the prevention of SARS-CoV-2.
People survive viral infections because their immune systems produce neutralizing antibodies against pathogens. Antibody formation only begins 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.
Antibody administration is the basis of immunotherapy, which was proposed by Emil von Behring a century ago and is currently also being tested in patients with COVID-19. However, serum therapy assumes that some patients have already survived the infection and that their immune systems have formed enough 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 components of the serum are generally transferred that can harm the patient (serum sickness).
Treatment with monoclonal antibodies would be more ideal, but even more difficult to implement in practice. These can now be produced in cell culture. Several antibody preparations have already been developed for the treatment of Ebola fever, two of which, namely MAb114 and REGN-EB3, have been shown to be more effective in a randomized study (NEJM 2019; 381: 2293-303). than the antiviral drug remdesivir, the Currently is 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 of the University of Utrecht looked for antibodies that could prevent viruses from entering cells. Researchers have raised 51 different antibodies against SARS-CoV-1 in cell cultures in recent years. These were chimeric antibodies with parts of muses and people.
In recent weeks, 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 can prevent infection of cells by SARS-CoV-2. 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 various antibodies is generally 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. However, before clinical trials can begin, 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 cells through the same receptor as SARS-CoV-1 and -2. © © rme / aerzteblatt.de
