Immunology of B7-H1 and its roles in human diseases.
B7-H1 was originally identified by homology analysis in comparison with B7-1 and B7-2, two molecules with important immunoregulatory functions. B7-H1, however, was broadly induced in the majority of peripheral tissues as well as hematopoietic cells. Upon binding to an as yet unidentified costimulatory receptor on primed T-cells, B7-H1 costimulates T-cell proliferation and preferentially induces interleukin 10 and interferon gamma. The costimulatory function of B7-H1 may be critical for enhancing maturation and differentiation of T-cells in lymphoid organs. Conversely, by binding to programmed death 1 receptors on activated T-cells and B-cells, B7-H1 may inhibit ongoing T-cell responses in peripheral tissues by inducing apoptosis and arresting cell-cycle progression. Although a positive regulatory role of B7-H1 has been demonstrated in vitro and in various animal models, a negative regulatory role of B7-H1 has also been documented in human diseases, including cancer, rheumatoid arthritis, and human immunodeficiency virus infection. Delineation of the complex interactions between B7-H1 and its receptors as well as its interplay with other ligands is critical for understanding this new immunoregulatory system. Precise manipulation of B7-H1 and its receptors may provide unique opportunities for designing new disease treatments.
Tamura
Hideto
H
Third Department of Internal Medicine, Nippon Medical School, Tokyo, Japan. tam@nms.ac.jp
Ogata
Kiyoyuki
K
Dong
Haidong
H
Chen
Lieping
L
D000818:Animals; D015703:Antigens, CD; D001327:Autoimmune Diseases / Q000209:etiology / Q000276:immunology*; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D060890:B7-H1 Antigen; D001798:Blood Proteins; D006801:Humans; D007109:Immunity; D008562:Membrane Glycoproteins; D009369:Neoplasms / Q000209:etiology / Q000276:immunology*; D010455:Peptides; D013601:T-Lymphocytes / Q000276:immunology
D015703:Antigens, CD; D018122:B7-1 Antigen; D060890:B7-H1 Antigen; D001798:Blood Proteins; C423236:CD274 protein, human; D008562:Membrane Glycoproteins; D010455:Peptides