title: Immunoregulatory role of B7-H1 in chronicity of inflammatory responses.
abstract: Pathogenesis of most chronic human diseases, including chronic infections, autoimmune diseases and cancers, often involves a persistent, unresolved inflammatory response. The molecular mechanisms that determine the conversion of an acute inflammatory response into a chronic process had puzzled researchers for many years. Recent studies reveal that B7-H1 (CD274, PD-L1), a newly identified co-stimulatory molecule, possesses dual functions of co-stimulation of naive T cells and inhibition of activated effector T cells. The aberrant cellular expression and deregulated function of B7-H1 have been reported during chronic viral and intracellular bacterial infection, as well as in many autoimmune diseases and cancers. Importantly, the deregulation of B7-H1's dual functions appears to be associated with a prolonged and incomplete immune response by luring naive T cells for activation and dampening activated effector T cells. Moreover, development of strategies targeting B7-H1 signals provides a new and promising approach to manipulate the devastating diseases associated with chronic inflammation. Thus, B7-H1 may play a critical immunoregulatory role in the chronicity of inflammatory responses.
authors.affiliation: Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA. dong.haidong@mayo.edu
authors.forename: Haidong
authors.initials: H
authors.lastname: Dong
authors.forename: Xianming
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000502:physiology*; D015551:Autoimmunity; D060890:B7-H1 Antigen; D001424:Bacterial Infections / Q000276:immunology*; D002908:Chronic Disease; D006801:Humans; D007249:Inflammation / Q000276:immunology; D009369:Neoplasms / Q000276:immunology*; D014777:Virus Diseases / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D060890:B7-H1 Antigen; C423236:CD274 protein, human