Figure 5.

CAR (B2) T cells lysed Hep3B tumor by targeting inducible PD-L1 and improved CAR-T efficacy in bispecific CAR and combination manners

(A) Inducible PD-L1 expression in Hep3B cells upon 50 μg/mL IFN-γ stimulation followed by depletion of IFN-γ at 24 h. (B) Inducible PD-L1 expression in the Hep3B cells after 24-h incubation with CAR (B2) T cells at an E/T ratio of 1:2. Shown are IFN-γ levels in cell supernatants of CAR (CD19) T cells or CAR (B2) T cells co-cultured with Hep3B cells. (C) Schematic of the Hep3B xenograft NSG model infused i.p. with five million CAR (B2) T cells and CAR (CD19) T cells after 12 days of tumor inoculation. (D) Representative bioluminescence image of Hep3B tumor growth in the xenograft model. (E) Tumor bioluminescence growth curve. (F) Inducible PD-L1 expression in Hep3B cells co-cultured with GPC3 CAR-T cells at an E/T ratio of 1:2 or 1:1 for 24 h. (G) Strategy of bispecific CAR-T cells and combination CAR-T cells targeting GPC3 and PD-L1. (H) Cytolytic activity of CAR-T cells on Hep3B cells after 24- or 72-h incubation in vitro. (I) TNF-α, IL-2, and IFN-γ concentration in the co-culture supernatant from (H) as measured by ELISA. Values represent mean ± SEM. ∗∗p < 0.01; ∗∗∗p < 0.001; ∗∗∗∗p < 0.0001.