title: Soluble B7-H1: differences in production between dendritic cells and T cells.
abstract: Tumor cells aberrantly express several T cell inhibitory molecules including members of the B7-H co-regulatory family. Presumably tumor-expressed B7-H1 and B7-H3 confer resistance to elimination by the immune system. In addition, elevated levels of soluble B7-H1 (sB7-H1) has been identified in the sera of cancer patients, including renal carcinoma patients and is associated with increased cancer related death. Here we report that sB7-H1 is produced and released by activated mature dendritic cells (mDC). Immature DC, macrophages, monocytes, or T cells are refractory to releasing sB7-H1. Exposure of CD4+ and CD8+ T cells to mDC-derived sB7-H1 molecules induced apoptosis. These data suggest that the immunobiology of B7-H1 is perhaps more complex than previously thought. sB7-H1 molecules may represent an unanticipated contributing factor to immune homeostasis. That both immune and tumor cells can be sources of sB7-H1 suggests that optimization of co-regulatory blockade immunotherapy for solid malignancies of necessity will require impact of targeting tumor and immune-derived B7-H1 molecules.
authors.forename: Xavier
authors.initials: X
authors.lastname: Frigola
authors.forename: Brant A
authors.initials: BA
authors.lastname: Inman
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Krco
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Susan M
authors.initials: SM
authors.lastname: Harrington
authors.forename: Peggy A
authors.initials: PA
authors.lastname: Bulur
authors.forename: Allan B
authors.initials: AB
authors.lastname: Dietz
authors.forename: Haidong
authors.initials: H
authors.lastname: Dong
authors.forename: Eugene D
authors.initials: ED
authors.lastname: Kwon
mesh_terms: D017209:Apoptosis; D060890:B7-H1 Antigen / Q000096:biosynthesis*; D002292:Carcinoma, Renal Cell / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism*; D006706:Homeostasis / Q000276:immunology*; D006801:Humans; D007680:Kidney Neoplasms / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*
chemical_list: D060890:B7-H1 Antigen