At present, serological diagnostics for COVID-19 are only offered based on proteins. In addition, to unexpected false positives, clinical diagnostics specifically report problems with previous infections with related Corona viruses. This is because the recognition sites of the patients’ antibodies (epitopes) are only partly specific to SARS-CoV-2, while others are found in many related Corona viruses.
Therefore, in future, serological tests will also have to be developed on the basis of defined epitopes of SARS-CoV-2 or other Corona viruses which permit both simple and highly individualised diagnostics with the help of different specific and ubiquitous epitopes. The Ligand Development working group at Fraunhofer IZI has comprehensive experience in identifying epitopes directly from serums. It is assumed that SARS-CoV-2 infections lead to a strongly personalised immune response which is shaped by previous Corona infections as in the case of epitope diagnostics of food allergies (low allergen, food allergen) for various foods.
However, in all diagnostic activities, the serums obtained from infected patients are pre-treated to inactivate the virus before the serums can be used in testing. This inactivation also inactivates a part of the antibodies in any case. This, in turn, might make the reproducibility and establishment of the complex epitope-based diagnostics more difficult. In the run-up to other projects, CoV-tot aims to establish the influence which various processes have on the range of the remaining antibodies to enable the clinical project partners to optimally prepare their samples. At the same time, the research team will also identify the first potential diagnostic epitopes.