Development of bioanalytical cell microarrays for prognosis before and follow-up monitoring after organ transplantation

• Applicant: Professorin Dr. Cornelia Blume, since 4/2024
• Subject Area: Hematology, Oncology
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 407319461

The major task of the immune system is the prevention of infections by pathogens (exogenous structures). Often organ grafts are recognized as exogenous leading to rejections. The aim of this project is the development of a specific and standardized, bioanalytical immune assay, facilitating reliable prognosis and quantitative monitoring of graft rejections before and after organ transplantation. Proteins, human leukocyte antigens (HLA), play the key role in the immunological discrimination process between endogenous and exogenous. The immune system of the organ recipient generates antibodies against exogenous HLA of the transplanted organ leading to rejections (antibody-mediated rejections). Therefore, the detection of HLA antibodies of the organ recipient is as important for the prognosis of graft suitability as the early identification of HLA antibodies indicative of rejections. However, current methods in antibody diagnostics exhibit major bottlenecks: Lymphocyte-based assays are used, which do possess limited sensitivity and specificity. Alternatively recombinant produced HLA is used, whose structure differs from the native HLA proteins of the organ resulting in unnaturally strong binding of antibodies. Besides antibodies against HLA, further antibodies (Non-HLA antibodies) are able to cause a graft rejection, which are not detected by these methods.To overcome these limitations, vital endothelial progenitor cells (EPCs) of an organ donor are used for antibody diagnostics in the proposed project. These cells differentiate into endothelial cells, which possess a donor specific pattern of HLA and Non-HLA proteins. Since the endothelium of transplanted organ grafts is the most relevant contact between the donated organ and the immune system of the recipient, it plays a key role in the development of rejections. Upon contact of EPCs with recipient serum, serum antibodies, which mediate rejections, bind to their native protein counterparts on the membrane of these cells with their natural affinity and can be detected reliably. To allow the use of small amounts of EPCs isolated from one blood sample for diagnostics, miniaturized living cell microarrays will be developed in this project. Using inkjet-nanoprinting, a few thousand vital cells can be applied for one diagnostic assay. As a result, with the small isolated cell amount a variety of assays can be performed in parallel in a short time. Printed, native cells shall be frozen and stored for a follow-up monitoring after the transplantation, making further donor blood samplings needlessly. The bioanalytical detection method will be developed initially by using human endothelial cells, which are available in sufficient quantity. Finally, the established method will be used for the screening of endothelial progenitor cells of potential organ donors and serum samples of potential recipients.

• DFG Programme: Research Grants
• Ehemalige Antragstellerin: Dr. Rebecca Jonczyk, until 3/2024