Figure 1.
To convey hepatic infiltration, memory T cells express high levels of liver-specific homing markers such as CD103, LFA-1, CXCR6 or CXCR3. Within the liver, TRM cells are exposed to a variety of environmental conditions that directly influence their maintenance, function and development; for example, nutrient deprivation and fatty acid oxidation, hypoxia and different inflammatory conditions. Besides the expression of IL-15, IL-7 and TGF-β, which directly effects hepatic stellate cells (HSCs), intrahepatic TRM cells are also able to secret pro-inflammatory molecules such as Interferon, Granzyme B, IL-17 and TNF-α. Liver-resident TRM cells have the ability to egress back into the bloodstream by upregulating CCR7 and S1PR1.