PD-1/PD-L1 Interaction Maintains Allogeneic Immune Tolerance Induced by Administration of Ultraviolet B-Irradiated Immature Dendritic Cells

Figure 6

PD-1/PD-L1 interaction controls alloantigen-responding effector T cells in tolerant mice. C3H mice were treated with Balb/c UVB-iDCs to induce alloantigen tolerance as described elsewhere. Six weeks later, CFSE-labeled naïve C3H spleen cells (1 × 10⁷/mouse) together with Balb/c spleen cells (1 × 10⁷/mouse) were intravenously injected into the tolerant mice. One group received intraperitoneal injection of anti-mouse PD-L1 mAb (100 μg/mouse); the other group received control IgG (100 μg/mouse) at the same day when cells were injected. On day 3, the above treatments were administered again. One group of naïve C3H mice was set up only receiving injection of both types of cells. On day 4 after cell injection, all mice were sacrificed and inguinal lymph nodes were collected and prepared for cell suspension. The proliferating CD4+ T cells and CD8+ T cells in CFSE+ lymph node cells were analyzed by flow cytometry. (a) Representative flow cytometric data on CFSE-labeled CD4+ T cell proliferation in each group were shown; (b) representative flow cytometric data on CFSE-labeled CD8+ T cell proliferation in each group were shown; ((c) and (d)) the summary of CD4+ and CD8+ T cell proliferation was shown, respectively. Data represent mean ± standard error. . The values were calculated using one-way ANOVA.

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