Irreversible electroporation combined with anti-programmed cell death protein 1 therapy promotes tumor antigen-specific CD8+ T cell response

Figure 1 Establishment of pancreatic cancer model and ablation parameters. A: Schematic drawing of the study design. C57BL/6 mice were enrolled for treatment once the tumor size reached about 10 mm; B: Tumor growth on day 20; C: Irreversible electroporation procedure was performed with two electrodes; D: Ablation parameters (1200 kV/cm, 70 pulses, 70 μs). IRE: Irreversible electroporation; PD-1: Programmed cell death protein 1.

Figure 2 Irreversible electroporation combined with anti-programmed cell death protein 1 treatment increased T lymphocyte infiltration in peripheral blood cells. A: Percentages of CD3⁺ T cells within a single-cell suspension of tumor tissues; B: Percentages of CD4⁺ T cells; C: Percentages of CD8⁺ T cells; D: CD4⁺: CD8⁺ ratio (values represent mean ± standard deviation, ^aP < 0.05, ^bP < 0.01, ^cP < 0.001). IRE: Irreversible electroporation; PD-1: Programmed cell death protein 1.

Figure 3 Irreversible electroporation combined with anti-programmed cell death protein 1 treatment increased peripheral blood cell infiltration of natural killer and B cells. A: Percentages of natural killer cells; B: Percentages of B cells (values represent mean ± standard deviation, ^aP < 0.05, ^bP < 0.01, ^cP < 0.001). IRE: Irreversible electroporation; NK: Natural killer; PD-1: Programmed cell death protein 1.

Figure 4 Irreversible electroporation combined programmed cell death protein 1 treatment modulated the concentrations of T helper type 1 cytokines in the peripheral blood. A: Plasma concentration of interleukin-2; B: Plasma concentration of tumor necrosis factor-β; C: Plasma concentration of interferon-γ (values represent mean ± standard deviation, ^aP < 0.05, ^bP < 0.01, ^cP < 0.001). IL-2: Interleukin-2; INF-γ: Interferon-γ; IRE: Irreversible electroporation; PD-1: Programmed cell death protein 1; TNF-β: Tumor necrosis factor-β.

Figure 5 Irreversible electroporation combined programmed cell death protein 1 treatment increased the mRNA expression of CD8 in the tumor tissue. Values represent mean ± standard deviation. ^aP < 0.01, ^bP < 0.001. IRE: Irreversible electroporation; PD-1: Programmed cell death protein 1. IRE: Irreversible electroporation; PD-1: Programmed cell death protein 1.

Figure 6 Irreversible electroporation combined programmed cell death protein 1 treatment increased the tumor regression. A: Tumor morphologic changes; B: Tumor size changes (values represent mean ± standard deviation, ^aP < 0.01, ^bP < 0.001). IRE: Irreversible electroporation; PD-1: Programmed cell death protein 1.