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. 2020 Mar 26;8(1):e000471. doi: 10.1136/jitc-2019-000471

Figure 2.

Figure 2

Cytotoxicity of anti-CD19 CAR T cells against cell lines with specific genetic background. (A) Indel mutations were induced in TP53 (in red) and ATM (in blue) genes of HG3 and MEC1 cell lines using CRISPR/Cas9. These mutations resulted in loss of the respective protein as demonstrated by western blotting. (B) Production of IFN-γ, as measured by ELISA, was significantly induced when CAR T cells were cultured with ATM-knockout and TP53-knockout cell lines as compared with CTRL T cells (Kruskal-Wallis test, p=0.0020). (C) Cytotoxicity of CAR T cells against generated TP53-knockout and ATM-knockout cell lines was measured in a 96 hours of coculture by flow cytometry. Results are expressed as percentage of CD19+ leukemia cell recovery after 4 days of culture relative to culture with CTRL T lymphocytes. (D) Target elimination over the cultivation period differed between TP53-knockout and ATM-knockout clones. Fifty-seven percent of TP53-knockout cells were able to proliferate in coculture with CAR T cells contrasted with 25% of ATM-knockout cells. CAR, chimeric antigen receptor; CTRL, control; IFN, interferon; n.s., not significant.