PERSONALIZED IMMUNE DIAGNOSTICS: EPITOPE MAPPING OF THE IMMUNOME

Abstract

Statistical phage display is a highly complex, but rapid and efficient way to identify “binding peptides” from a unique and specially designed library. It avoids repeated selection rounds and can therefore provide much more complex data than just a few sequences usually obtained with repeated peptide library selection. The complexity of the data analyzed is sufficient to cover hundreds of potential binder/target combinations in parallel.Applying this novel way to generate and analyze data from peptide phage display with antibodies allows to predict potential epitopes at amino acid resolution. Fingerprinting of monoclonal antibodies reveals the large variety of peptides binding to any given antibody. Independent of such laborious and failure prone methods like peptide arrays or phage display with antigen gene fragments. Surprisingly easy this can explain the specificity of antibodies and it is a valuable tool for antibody quality control.Beyond the application to individual antibodies we are able to analyze the immunome of patient sera. Theoretically, there are hundreds of antibody molecules for each recently encountered antigen epitope in a few µl. This is enough to define individual antibody epitopes. Since a single patient sample allows to record the entire immunome data, there is a tremendous amount of information hidden in the data sets we obtain. Nevertheless, all patients show different epitope patterns and for the generation of diagnostic tools we must compare many different sera. Results from examples will be given for allergic disease, viral infection diagnostics and the vaccine imprint on the immunome of one individual patient history.In infectious disease diagnostics (e.g. EBV, COVID-19, influenza) epitope-based kits can provide a robust analysis of existing and past disease as well as effective monitoring of vaccine efficacy. The aspect that the immune system carries the memories of antigens at least for many months allows a complex analysis even identifying different viral strains in a single experiment.In allergic disease we carried out epitope mapping with hundreds of sera from patients with sensibilization to allergenic food ingredients. Predicted epitopes were validated by binding IgE and IgG from many more patient sera for the main food allergy agents. Since peptide epitope diagnostics do not suffer from the undefined cross reactivities of present methods, we are gathering now a rather different understanding of what food allergies really are. In particular, we can also use IgG measurement based on immunoassays with epitopes, which has been regarded as impossible.Presently we are extending our work also in auto-immune diseases connected to long-COVID and psychiatric diseases.