Antigen processing and presentation in the liver

Abstract

The liver is an important site of infectious, parasitic, autoimmune, and malignant diseases. Immune responses and their modulation within the liver are critical to the outcome of these conditions and also in liver transplantation. Immune responses in, or elicited by, the liver can result in tolerance rather than immunity. Hepatic tolerance was demonstrated initially by the acceptance of liver allografts across major histocompatibility complex (MHC) barriers, without immunosuppressive therapy. In addition, the liver appears to play an important role in the induction of oral tolerance, as well as in the development/persistence of certain viral infections and cancer. Underlying mechanisms of this comparative immune privilege have not been validated convincingly. However, in addition to its unique anatomical structure, hepatic APCs might be involved in this process (1). APCs exist in several forms within the liver and exhibit a spectrum of abilities to capture, process, and present antigen to immune effector cells. © 2007 Humana Press Inc.