Methods: The mRNA expression level of PD-L1 and PD-L2, the lig ands of PD-1, were investigated in mouse H22 cells as well as H22 tumor tissues by using semi-quantitative RT-PCR method.

• 方法:采用半定量 RT-PCR方法检测PD-1的配体PD-L1和PD-L2在小鼠H22肝癌细胞和癌组织中的表达水平,流式细胞仪检测其在激活T细 胞表面的表达;