Abstract 1769: A combination approach of a cellular library and single cell microfluidics analysis for the rapid selection of CAR-T cells

Within the last decade CAR-T cells have changed the landscape of treatment regimen for leukemia and myeloma, which is reflected by the first FDA approval of this class of living drugs in 2017. As of today, the clinical trial situation aims on CAR-T applicability in solid tumors, which is more arduous due to antigen heterogeneity and limited CAR-T persistence. More personalized and multi-target oriented cellular products may offer a solution to overcome these problems but then CAR identification and selection display the major bottleneck in the drug development process. Usually, matching scFvs are selected from targeting screens of a phage-display library and hits are subsequently cloned in CAR backbones and tested for functionality and possible limiting factors as the occurrence of tonic signaling. This makes the whole process very time consuming and laborious. Within this project, we propose a novel CAR-T selection method that rapidly shortens the discovery procedure. We have developed a full length CAR library in nS/MARt DNA vectors that is electroporated in a Jurkat reporter cell line reflecting entirely its full diversity. By this, we can quickly identify the amount of tonic signaling CARs and exclude them from further selection. For on-target selection we first perform a bulk pre-selection followed by a single cell functionality screening using the Berkeley Lights Lightning™ device. This allows us to export hits as clonal viable cells that undergo long length Nanopore CAR-RNA sequencing. Our findings show the feasibility of our approach and that it can shorten the timeframe needed for the full selection process from weeks to days. Citation Format: Eren Boga, Luisa Berger, Alice De Roia, Inka Zörnig, Robert Embacher, Stefan B. Eichmüller, Dirk Jäger, Richard Harbottle, Patrick Schmidt. A combination approach of a cellular library and single cell microfluidics analysis for the rapid selection of CAR-T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1769.