title: In vivo costimulatory role of B7-DC in tuning T helper cell 1 and cytotoxic T lymphocyte responses.
abstract: B7-DC, one of the recently described B7 family members, has the capacity to inhibit T cell responses via engagement of the immunoreceptor tyrosine-based inhibitory motif-containing inhibitory PD-1 receptor as well as enhance responses via an as yet unidentified costimulatory receptor. B7-DC is highly homologous to a coinhibitory B7 family member, B7-H1, which also binds PD-1. It is currently unclear which B7-DC function-costimulation or inhibition-predominates in vivo. To study in vivo functions of B7-DC, we evaluated immune responses in B7-DC knockout (KO) mice. Although not eliminated, interferon-gamma (IFN-gamma) production by CD4 T cells and IFN-gamma-dependent humoral responses were reduced in B7-DC KO mice relative to wild type mice. Antigen-specific CD8 T cell responses and cytotoxic T lymphocyte (CTL) activity were also diminished in B7-DC KO mice. Hepatic tumors grew more quickly in B7-DC KO mice, associated with a decrease in intrahepatic tumor-specific CD8 T cells. These results highlight the contrasting in vivo roles of B7-DC and B7-H1 and indicate that B7-DC functions as a tuning molecule, selectively augmenting T helper 1 and CTL responses.
authors.affiliation: Sidney Kimmel Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
authors.forename: Tahiro
authors.initials: T
authors.lastname: Shin
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yoshimura
authors.forename: Takako
authors.initials: T
authors.lastname: Shin
authors.forename: Emily B
authors.initials: EB
authors.lastname: Crafton
authors.forename: Haruo
authors.initials: H
authors.lastname: Tsuchiya
authors.forename: Franck
authors.initials: F
authors.lastname: Housseau
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Koseki
authors.forename: Richard D
authors.initials: RD
authors.lastname: Schulick
authors.forename: Lieping
authors.initials: L
authors.lastname: Chen
authors.forename: Drew M
authors.initials: DM
authors.lastname: Pardoll
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000276:immunology; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology*; D002450:Cell Communication / Q000235:genetics / Q000276:immunology*; D007371:Interferon-gamma / Q000096:biosynthesis; D008114:Liver Neoplasms, Experimental / Q000235:genetics / Q000276:immunology / Q000473:pathology; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D061027:Programmed Cell Death 1 Ligand 2 Protein; D061026:Programmed Cell Death 1 Receptor; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology*
chemical_list: D000943:Antigens, Differentiation; D018122:B7-1 Antigen; C491383:Pdcd1 protein, mouse; C556978:Pdcd1lg2 protein, mouse; D061027:Programmed Cell Death 1 Ligand 2 Protein; D061026:Programmed Cell Death 1 Receptor; D007371:Interferon-gamma