Liver: An organ with predominant innate immunity.
Blood circulating from the intestines to the liver is rich in bacterial products, environmental toxins, and food antigens. To effectively and quickly defend against potentially toxic agents without launching harmful immune responses, the liver relies on its strong innate immune system. This comprises enrichment of innate immune cells (such as macrophages, natural killer, natural killer T, and gammadelta T cells) and removal of waste molecules and immunologic elimination of microorganisms by liver endothelial cells and Kupffer cells. In addition, the liver also plays an important role in controlling systemic innate immunity through the biosynthesis of numerous soluble pathogen-recognition receptors and complement components.


CONCLUSIONS
The liver is an organ with predominant innate immunity, playing an important role not only in host defenses against invading microorganisms and tumor transformation but also in liver injury and repair. Recent evidence suggests that innate immunity is also involved in the pathogenesis of liver fibrosis, providing novel therapeutic targets to treat such a liver disorder.
Gao
Bin
B
Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA. bgao@mail.nih.gov
Jeong
Won-Il
WI
Tian
Zhigang
Z
D000818:Animals; D003167:Complement Activation; D003165:Complement System Proteins / Q000502:physiology; D022781:Hepatocytes / Q000276:immunology / Q000502:physiology; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology; D007728:Kupffer Cells / Q000276:immunology; D008099:Liver / Q000276:immunology*; D008102:Liver Circulation / Q000276:immunology / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology
D003165:Complement System Proteins