title: Differential effects of B7-1 and B7-2 on the costimulation of mouse nonspecific cytotoxic T lymphocyte development in response to anti-CD3 antibody.
abstract: Despite extensive study, the relative contribution of B7-1 and B7-2 molecules to the costimulation of cytotoxic T lymphocyte (CTL) activation remains controversial. We used blocking mAbs to B7-1 and B7-2 molecules to determine the role of these B7 family members in the in vitro induction of mouse nonspecific CTL in response to soluble anti-CD3 mAb. Optimal induction of anti-CD3-activated killer-T (AK-T) cells was found to require interactions with B7-2 on residual accessory cells in nylon wool-nonadherent spleen cell preparations during the first 12 h of culture in the presence of anti-CD3 mAb. Because B7-1 is not expressed at high enough levels on residual accessory cells in primary T cell cultures to be an effective ligand for CD28, we used LPS-stimulated B cells, which express substantial B7-1, in addition to B7-2, to determine the contribution of B7-1 to AK-T cell development. Compared with B7-2, the contribution of B7-1 to the costimulation of AK-T cells in this system was modest because anti-B7-1 mAb had only a minimal inhibitory effect on the generation of cytotoxicity, whereas anti-B7-2 mAb strongly inhibited AK-T cell development. Anti-CD3-induced cytotoxicity of T cells from CD4 knockout mice and CD4-depleted nylon wool-nonadherent spleen cells from wild-type mice was inhibited by anti-B7-2 mAb, implying that B7-2 is able to bind directly to CD28 on CD8+ T cells and costimulate their activation. B7-1 blockade, on the other hand, did not affect the costimulation of CD8+ T cells. Blockade of B7-2/ CD28 interactions with anti-B7-2 mAb strongly inhibited granzyme B, but not perforin or Fas ligand gene expression, suggesting an explanation for the inhibitory effect of anti-B7-2 mAb on AK-T cell development. These data indicate that B7-2 is superior to B7-1 as a costimulator of mouse AK-T cell induction.
authors.affiliation: Department of Microbiology & Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: A P
authors.initials: AP
authors.lastname: Makrigiannis
authors.forename: B L
authors.initials: BL
authors.lastname: Musgrave
authors.forename: D W
authors.initials: DW
authors.lastname: Hoskin
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000096:biosynthesis / Q000276:immunology*; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology; D018122:B7-1 Antigen / Q000096:biosynthesis / Q000276:immunology*; D051940:B7-2 Antigen; D018106:CD28 Antigens / Q000096:biosynthesis / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology* / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D005260:Female; D053804:Granzymes; D007694:Killer Cells, Natural / Q000276:immunology; D008024:Ligands; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008934:Mitogens / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; D017252:CD3 Complex; C497965:Cd86 protein, mouse; D008024:Ligands; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D008934:Mitogens; D053804:Granzymes; C509214:Gzmb protein, mouse; D012697:Serine Endopeptidases