title: The liver as a lymphoid organ.
abstract: The liver receives blood from both the systemic circulation and the intestine, and in distinctive, thin-walled sinusoids this mixture passes over a large macrophage population, termed Kupffer cells. The exposure of liver cells to antigens, and to microbial products derived from the intestinal bacteria, has resulted in a distinctive local immune environment. Innate lymphocytes, including both natural killer cells and natural killer T cells, are unusually abundant in the liver. Multiple populations of nonhematopoietic liver cells, including sinusoidal endothelial cells, stellate cells located in the subendothelial space, and liver parenchymal cells, take on the roles of antigen-presenting cells. These cells present antigen in the context of immunosuppressive cytokines and inhibitory cell surface ligands, and immune responses to liver antigens often result in tolerance. Important human pathogens, including hepatitis C virus and the malaria parasite, exploit the liver's environment, subvert immunity, and establish persistent infection.
authors.affiliation: David H. Smith Center for Vaccine Biology and Immunology, Aab Institute for Biomedical Research, University of Rochester Medical Center, Rochester, New York 14642, USA. nick_crispe@urmc.rochester.edu
authors.forename: Ian Nicholas
authors.initials: IN
authors.lastname: Crispe
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D022781:Hepatocytes / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism; D007728:Kupffer Cells / Q000276:immunology; D008099:Liver / Q000166:cytology / Q000276:immunology*; D008102:Liver Circulation / Q000276:immunology; D008221:Lymphoid Tissue / Q000166:cytology / Q000276:immunology*; D055611:Natural Killer T-Cells / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D051193:Toll-Like Receptors / Q000276:immunology / Q000378:metabolism
chemical_list: D051193:Toll-Like Receptors