title: Blockade of B7-H1 on macrophages suppresses CD4+ T cell proliferation by augmenting IFN-gamma-induced nitric oxide production.
abstract: PD-1 is an immunoinhibitory receptor that belongs to the CD28/CTLA-4 family. B7-H1 (PD-L1) and B7-DC (PD-L2), which belong to the B7 family, have been identified as ligands for PD-1. Paradoxically, it has been reported that both B7-H1 and B7-DC co-stimulate or inhibit T cell proliferation and cytokine production. To determine the role of B7-H1 and B7-DC in T cell-APC interactions, we examined the contribution of B7-H1 and B7-DC to CD4+ T cell activation by B cells, dendritic cells, and macrophages using anti-B7-H1, anti-B7-DC, and anti-PD-1 blocking mAbs. Anti-B7-H1 mAb and its Fab markedly inhibited the proliferation of anti-CD3-stimulated naive CD4+ T cells, but enhanced IL-2 and IFN-gamma production in the presence of macrophages. The inhibition of T cell proliferation by anti-B7-H1 mAb was abolished by neutralizing anti-IFN-gamma mAb. Coculture of CD4+ T cells and macrophages from IFN-gamma-deficient or wild-type mice showed that CD4+ T cell-derived IFN-gamma was mainly responsible for the inhibition of CD4+ T cell proliferation. Anti-B7-H1 mAb induced IFN-gamma-mediated production of NO by macrophages, and inducible NO synthase inhibitors abrogated the inhibition of CD4+ T cell proliferation by anti-B7-H1 mAb. These results indicated that the inhibition of T cell proliferation by anti-B7-H1 mAb was due to enhanced IFN-gamma production, which augmented NO production by macrophages, suggesting a critical role for B7-H1 on macrophages in regulating IFN-gamma production by naive CD4+ T cells and, hence, NO production by macrophages.
authors: Department of Immunology, Juntendo University School of Medicine, Hongo, Tokyo, Japan. tyama@med.juntendo.ac.jp
authors: Tomohide
authors: T
authors: Yamazaki
authors: Hisaya
authors: H
authors: Akiba
authors: Akemi
authors: A
authors: Koyanagi
authors: Miyuki
authors: M
authors: Azuma
authors: Hideo
authors: H
authors: Yagita
authors: Ko
authors: K
authors: Okumura
mesh_terms: D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018122:B7-1 Antigen / Q000276:immunology / Q000502:physiology; D060890:B7-H1 Antigen; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D006224:Cricetinae; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006131:Growth Inhibitors / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D007371:Interferon-gamma / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D008213:Lymphocyte Activation / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000096:biosynthesis* / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052247:Nitric Oxide Synthase Type II; D009952:Ornithine / Q000031:analogs & derivatives / Q000494:pharmacology; D010455:Peptides / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000502:physiology; D061027:Programmed Cell Death 1 Ligand 2 Protein; D014366:Tryptophan Oxygenase / Q000037:antagonists & inhibitors; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D019138:Antibodies, Blocking; D018122:B7-1 Antigen; D060890:B7-H1 Antigen; C498919:Cd274 protein, mouse; D004791:Enzyme Inhibitors; D006131:Growth Inhibitors; D008562:Membrane Glycoproteins; C556978:Pdcd1lg2 protein, mouse; D010455:Peptides; D061027:Programmed Cell Death 1 Ligand 2 Protein; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; C065027:N(G)-iminoethylornithine; D007371:Interferon-gamma; D009952:Ornithine; D014366:Tryptophan Oxygenase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse