The role of hepatic immune regulation in systemic immunity to viral infection
Medical microbiology and immunology, 2015•Springer
The liver has particular immune functions attributed by its unique microenvironment and its
liver-resident cell populations. During autoimmunity and viral hepatitis, the liver serves as
target for effector responses of immune cells. However, skewing of effector T cell functions
through tolerogenic liver-resident antigen-presenting cells and through the immune
regulatory hepatic microenvironment. Importantly, the liver also participates in shaping
systemic antigen-specific immunity. Local antigen-presenting cell populations, in particular …
liver-resident cell populations. During autoimmunity and viral hepatitis, the liver serves as
target for effector responses of immune cells. However, skewing of effector T cell functions
through tolerogenic liver-resident antigen-presenting cells and through the immune
regulatory hepatic microenvironment. Importantly, the liver also participates in shaping
systemic antigen-specific immunity. Local antigen-presenting cell populations, in particular …
Abstract
The liver has particular immune functions attributed by its unique microenvironment and its liver-resident cell populations. During autoimmunity and viral hepatitis, the liver serves as target for effector responses of immune cells. However, skewing of effector T cell functions through tolerogenic liver-resident antigen-presenting cells and through the immune regulatory hepatic microenvironment. Importantly, the liver also participates in shaping systemic antigen-specific immunity. Local antigen-presenting cell populations, in particular liver sinusoidal endothelial cells (LSECs), cross-present soluble, circulating or hepatocyte-derived antigens to naïve CD8 T cells. Upon priming by cross-presenting LSECs, naïve CD8 T cells develop into a unique population of antigen-experienced memory-like T cell population that can be reactivated in an inflammatory context to protect against infection with viruses or bacteria. Furthermore, upon prolonged inflammatory TNF-dependent signaling, the induction of intrahepatic myeloid cell aggregates for T cell population expansion (iMATEs) is observed in liver tissue. iMATEs are formed by inflammatory monocytes developing into dendritic cells and function to attract recently activated CD8 T cells. Those CD8 T cells located within the cocoon-like iMATE structure show strong proliferation initiated by co-stimulatory signaling. Locally expanded CD8 T cells are key to control acute and chronic viral infections. The mechanistic understanding of local hepatic T cell priming and local expansion of effector CD8 T cells will help to develop novel therapeutic vaccination strategies.
Springer