Figure 5.

IL7 and IL12 secreting MSCs enhance CAR driven T cell proliferation and reduce activation induced cell death (AICD). Anti-CEA CAR T cells were CFSE labeled and co-cultivated (2.5 × 10⁴ cells/well) with or without non-modified or IL7/IL12-modified MSCs in 96-well plates (5000 cells/well) that were coated with the anti-idiotypic mAb BW2064 (4 µg/mL) for CAR engagement or with PBS for control. After 5 days cells were recovered, stained with an anti-IgG-PE antibody to detect the CAR and analyzed by flow cytometry. The number of proliferating T cells was determined by CFSE dilution, dead cells were identified by 7-AAD staining (1 µg/mL) and the number of proliferating cells was determined. (A) CAR T cell proliferation in presence or absence of MSCs; (b,c) number of rapidly cycling CAR T cells within the observation period; (B) flow cytometric histograms of a typical experiment after stimulation with the anti-idiotypic mAb, (C) summary of rapidly cycling CAR T cells. (D) AICD of CAR T cells in presence or absence of MSCs. Values represent the mean of replicates +/− standard deviation (SD). Significant differences were calculated by Student’s T test. p < 0.05, n.s., not significant.