CD4 and neoplasm: In addition, silencing PD-L1 or PD-L2 specifically on DCs enhanced proliferation of tumor-specific CTLs and CD4+ T-cells, augmented production of IFN-γ, tumor-necrosis factor alpha (TNFα), IL-2, IL-5, and IL-12 and promoted cytolysis of tumor cells in vitro (119–123).