Figure 2. CD28 signaling improves lytic capacity and cytokine production of affinity-tuned CD38-CAR T cells.

(A) Functional experiments were performed seven to ten days after transduction. The series of high and low affinity CAR T cells were incubated with Firefly-Luciferase-transduced human MM cell line UM9 (n=3 for each condition). The luciferase signal produced by surviving UM9 cells was determined after 16–24 hours within 15 minutes after the addition of 125 μg/mL beetle luciferin. % lysis cells = 1 − (BLI signal in treated wells / BLI signal in untreated wells) × 100%. (B) 24 hours after co-incubation with UM9 (E:T ratio 1:1), cell supernatants were harvested to measure cytokine secretion with a flow cytometry-based assay. Graph shows the secretion of IFN-γ, TNF and IL-2. (C) Comparison of cytokine production of CARB1 with different costimulatory designs. Mean values (+/− SEM) are shown (n=3 each condition). * indicates p value <0.05 ** <0.01 and *** <0.001 using one-way analysis of variance and subsequent multiple comparison, ns: non-significant.