Fig. 2

Multiple experimental approaches through genetic deletion of PD-L1 on tumor cells or the hosts can be employed to elucidate the contribution of PD-L1 in mediating tumor evasion. a PD-L1-sufficient or PD-L1 knock out (KO) tumor cells are inoculated into WT immunocompetent hosts, and the source of PD-L1 contributed to tumor escape is determined by the regression of PD-L1-deficient tumors. b WT tumors are inoculated into WT or PD-L1-deficient hosts, and the source of PD-L1 contributed to tumor escape is determined by the tumor regression in PD-L1 KO hosts. c, d PD-L1-KO tumors are inoculated into WT host (c), or WT tumors are inoculated into PD-L1 KO hosts (d), and the source of PD-L1 contributed to tumor escape is determined by the therapeutic effects of anti-PD-L1 antibody