An important line of defence in the fight against the new corona virus SARS-CoV-2 is the formation of neutralising antibodies. These can eliminate the intruders and have great potential to be used for prevention and treatment of SARS-CoV-2 infection.

A team of researchers led by Prof. Florian Klein (Cologne University Hospital) and the German Center for Infection Research (DZIF) has further elucidated how these antibodies develop and has isolated potent SARS-CoV-2 neutralizing antibodies. Together with Boehringer Ingelheim, the researchers are currently characterizing and developing these antibodies further. It is expected that they will enter the stage of clinical development later this year. The results were published today (July 07, 2020) in the journal Cell.

"Our goal was to better understand the immune response to SARS-CoV-2 and to identify highly potent antibodies that could be used to prevent and treat COVID-19," explained Prof. Klein, Director of the Institute of Virology at the Cologne University Hospital and Principal Investigator at the DZIF. "We assume that such antibodies are effective for several weeks and may protect against COVID-19 during this period," added Dr. Christoph Kreer, who conducted the work together with Dr. Matthias Zehner in Cologne.

In close collaboration with scientists from Marburg, Frankfurt, Munich, Tübingen and Israel, the researchers investigated the SARS-CoV-2 antibody response in twelve individuals recovered from COVID-19. They examined more than 4000 SARS-CoV-2-specific B cells on a single cell level and were able to partly decode the humoral immune response to SARS-CoV-2. They reconstructed 255 antibodies in the laboratory, which were examined by Prof. Stephan Becker's laboratory in Marburg for their ability to neutralise the novel coronavirus SARS-CoV-2. In total, 28 neutralising antibodies were found.

"Interestingly, many antibodies showed only a small number of mutations. This means that only minor changes were necessary to effectively recognise and neutralise the virus" says Dr. Zehner. In fact, in blood samples collected before the pandemic, the scientists found B cells carrying similar antibody characteristics to those of SARS-CoV-2 neutralising antibodies. This may suggest that SARS-CoV-2 antibodies can be readily formed and that an active vaccine may provide rapid protection.

The antibodies have been developed for protecting against and treating COVID-19. In addition, these antibodies could be used for 'post-exposure prophylaxis. Here antibodies would be applied after contact with an infected individual. "This form of intervention could be of particularly interest for stopping localised outbreaks and for preventing disease progression in people at risk," said Prof. Klein. The scientists expect that first clinical trials will be performed at the end of 2020.