title: B7S1, a novel B7 family member that negatively regulates T cell activation.
abstract: T cell activation by antigen-presenting cells (APC) is regulated by positive and negative costimulatory molecules in the B7 family. Here we describe a novel addition in this family, designated as B7S1, which is uniquely anchored to the cell membrane via a GPI linkage. B7S1 is expressed on professional APC and widely distributed in nonlymphoid tissues. A soluble B7S1-Ig fusion protein binds to activated but not naive T cells. B7S1-Ig inhibits T cell activation and IL-2 production. A monoclonal antibody that blocks binding of B7S1 to its receptor enhances T cell proliferation in vitro and exacerbates experimental autoimmune encephalomyelitis in vivo. This study identifies a novel negative regulator of T cell activation and further reveals complex costimulatory regulation of immune responses.
authors.affiliation: Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195, USA.
authors.forename: Durbaka V R
authors.initials: DV
authors.lastname: Prasad
authors.forename: Sabrina
authors.initials: S
authors.lastname: Richards
authors.forename: Xoi Muoi
authors.initials: XM
authors.lastname: Mai
authors.forename: Chen
authors.initials: C
authors.lastname: Dong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D060907:V-Set Domain-Containing T-Cell Activation Inhibitor 1
chemical_list: D018122:B7-1 Antigen; D007136:Immunoglobulins; D011993:Recombinant Fusion Proteins; D060907:V-Set Domain-Containing T-Cell Activation Inhibitor 1; C475826:VTCN1 protein, human; C475824:Vtcn1 protein, mouse