Immunobiology of hepatocarcinogenesis: Ways to go or almost there?

Figure 1 Mechanisms leading to CD8⁺ T cell suppression. Failure of CD8⁺ T cells to kill tumor cells involves signals from multiple cells including MDSC, Treg, and TAMs. The interaction of PD-L1 with PD-1 on the CD8⁺ T cell causes suppression and decrease in its effector function leading to decreased tumor cell death. Furthermore, the Galectin-9 and TIM-3 interaction on MDSC’s and IL-10 secretion by Treg cause a similar effect. PD-1: Programmed death 1; IL: Interleukine; TAM: Tumor associated macrophages; MDSC: Myeloid derived suppressor cells; TIM-3: T-cell immunoglobulin and mucin-domain containing-3; T_reg: Regulatory T cells.

Figure 2 Differentiation of naïve T cells. The Th0 T cell can differentiate into a variety of CD4⁺ cells based on stimulatory signals as seen above. TGF-β: Transforming growth factor beta; IFN-γ: Interferon gamma; IL: Interleukine; Treg: Regulatory T cells.