PerC B cells from Balb/c mice were isolated, pre-incubated with anti-PD-L1 and/or anti-PD-L2 mAb for 30 min, and injected to B6 mice through the tail vein. Isotype-matched control IgGs were used instead of anti-PD-L1 or anti-PD-L2 mAb. Rat IgG2b was used instead of anti-PD-L1 mAb, and Rat IgG2a was used instead of anti-PD-L2 mAb. Mice in the control group did not receive adoptive transfer of cells or mAbs. T-cell alloreactivity was determined by performing the CFSE-MLR assay 2 weeks after the intravenous injection. Upper row shows the mean SIs of CD4+ and CD8+ T cells, and lower row shows the mean PFs of CD4+ and CD8+ T cells; *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.00001. Data are presented as mean ± SEM, and are representative of two independent experiments with four to five mice per group.