Abstract 2145: Ex vivo phenotyping and potency monitoring of CD19 CAR T cells with a combined flow cytometry and impedance-based real time cell analysis workflow

Abstract

Abstract Immunotherapy harnesses the immune system to attack cancer cells. While immunotherapy holds tremendous promise for cancer treatment, significant challenges remain in clinical translation. Further development is still required to expand treatment to more cancers and minimize adverse effects. T-cell differentiation and exhaustion influence the establishment and persistence of CAR-expressing T cells. Evaluation of the potency of CAR T cells is essential for effective immunotherapies. Here, we study the potency of CAR-T cells using a combined impendence-based Real-Time Cell Analysis (RTCA) and flow cytometry cell analysis workflow for ex vivo cytolytic potency monitoring of CD19 CAR T cells (CART19). CART19 cell killing of CD19 expressing HEK-293 cells with different E:T (Effector to Target) ratio was monitored by the xCELLigience RTCA system. Concurrently, T cell cytokine production was measured on the NovoCyte Quanteon. This workflow provides a thorough examination of CART cell function, RTCA data demonstrates that CART19 killing is highly potent as well as being antigen-specific and dose-dependent. In conjunction, more cytokine was produced with higher numbers of effector CART19 cells. It was also observed that CART19 cells express stem memory cell (TSCM) markers, expressing activation and exhaustion markers after expansion. Co-culture with HEK-293-CD19 also results in increased expression of CD25, decreased expression of CD127 and upregulation of exhaustion markers, PD-1, TIM-3, and LAG-3. In summary, this study demonstrates the combination of RTCA and flow cytometry cell analysis is a powerful workflow for immunotherapy research and can be employed for QC in CAR T cell manufacturing. Citation Format: Li Zhao, Ming Lei, Peifang Ye, Yan Lu, Xiaoping Ji, Yu Yan, Lauren Jachimowicz, Garret Guenther, Nancy Li. Ex vivo phenotyping and potency monitoring of CD19 CAR T cells with a combined flow cytometry and impedance-based real time cell analysis workflow [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2145.