Optimizing T-cell functional avidity

• Applicant: Dr. Korbinian Kropp
• Subject Area: Hematology, Oncology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 490682454

Cell-based tumor immunotherapy comprises, among others, the infusion of T cells expressing tumor-specific T-cell receptors (TCR). In the context of TCR-mediated tumor immunotherapy successful elimination of tumor cells has been linked to high functional T-cell avidity, and some mechanisms that increase functional T-cell avidity have already been described. The core aim of this project is to uncover additional mechanisms that regulate this parameter. The host laboratory of Christopher A. Klebanoff has identified multiple genes (61 as of yet) that are either up- or downregulated in T cells upon TCR-mediated tumor-cell recognition. Whether these genes may also positively or negatively modulate functional T-cell avidity is not known yet. This will be investigated systematically in pooled CRISPR overexpression and knockout screens. The screens will be performed using a genetically engineered Jurkat T-cell line the endogenous TCR of which will be replaced in a one-step knockout/knock-in approach with the clinically relevant TCR 1G4. This TCR recognizes an HLA-A*02:01-restricted peptide processed from the cancer-germline antigen NY-ESO-1. In the CRISPR screens the candidate genes described above will be either deleted or overexpressed in 1G4-transgenic Jurkat cells and effects of these modifications on recognition of peptide-loaded target cells will be analyzed. Promising targets that either increase or decrease functional T-cell avidity will be further characterized and their therapeutic potential will be finally evaluated in a preclinical in vivo-mouse model. If none of the candidate genes described above yields encouraging results, CRISPR overexpression and knockout screening libraries will be used that target the whole genome in an unbiased manner. In summary, the overall goal of the project is to uncover therapeutic targets that improve TCR-mediated tumor immunotherapy.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professor Dr. Christopher A. Klebanoff