Simple test developed for detection of protective neutralising antibodies:
Infections with the coronavirus SARS-CoV-2 can take very different courses. While some people have no symptoms, others get seriously ill. An important question that often arises after surviving an infection is whether neutralising antibodies against the virus have been generated. These particulary important antibodies dock to the virus and prevent the virus from entering and multiplying in human cells. In this manner these antibodies protect the body from re-infection.

For detection of neutralising antibodies there are usually complex requirements as infectious viruses, living cells and laboratories with a high safety standard required. That’s why only a very limited amount of blood samples from convalescent patients can be tested for the presence of neutralising antibodies. “To change this, we have developed a very simple and rapid procedure that requires only two proteins that are important for the infection process: The spike protein of the virus and the protein ACE2 of the cell. If the binding of the spike protein to ACE2 is suppressed by serum antibodies, these antibodies are also able to prevent the infection of cells with the virus,” says Dr. Berislav Bosnjak from the Institute of Immunology at MHH. He is the first author of the study now published in the journal Cellular and Molecular Immunology.  The corresponding research project was funded by the Cluster of Excellence RESIST, the Corona Research Funding Programme of the State of Lower Saxony and the CRC 900.

“Our developed test provides the possibility now to analyse a large number of patients over a long period of time in clinical trials and to determine how long these important antibodies are present in the blood,” says Professor Dr. Reinhold Förster. The RESIST co-speaker leads the MHH Institute of Immunology and is the senior author of the study. At the moment, the new method is l only available for research purposes. However, it could potentially be adapted for routine diagnostics in the future.

Using already available techniques and comparing them with the new method, the team was able to show that about ten percent of people infected with SARS-CoV-2 had no protective antibodies in their blood. Those were mostly people who showed few symptoms ill only for a short time. On the contrary, patients with severe symptoms and longer disease courses produced much more antibodies. “It is still unclear which amount of neutralising antibodies is required to protect convalescents from re-infection. But with the test now available, it will be possible to answer this important question more quickly,” says Professor Förster.
There were other members of his Institute also involved in the study – as well as the MHH Institute of Virology, led by RESIST speaker Professor Dr. Thomas Schulz, the Institute of Transfusion Medicine and Transplant Engineering, teams from the MHH Clinic for Rheumatology and Immunology, the MHH Clinic for Pneumology and the German Primate Centre in Göttingen.

The photo shows Dr. Berislav Bosnjak (right) and Professor Dr. Reinhold Förster (left) in an MHH laboratory using the new test method.