title: Importance of B7-1-expressing host antigen-presenting cells for the eradication of B7-2 transfected P815 tumor cells.
abstract: We have previously shown that B7-2 (CD86)-transfected P815 tumor cells elicit tumor-eradicating immunity that leads to the regression of the B7-2+ P815 tumor after transient growth in normal DBA/2 mice. Here, we show that both the B7-2 and B7-1 (CD80) molecules contribute to the eradication of B7-2+ P815 tumors as treatment of the mice with both anti-B7-2 and anti-B7-1 mAb was required to prevent B7-2+ P815 tumor regression. The cells that expressed the B7-1 molecule following inoculation of B7-2+ P815 tumor cells into normal mice were not the tumor cells but rather host APCs including MAC-1+ cells present in the draining lymph nodes. Moreover, B7-1-expressing host APCs were found to be important for the rejection of B7-2+ P815 tumors as anti-B7-2 mAb alone, which was ineffective in preventing B7-2+ P815 tumor rejection by normal wild-type mice, was effective in preventing B7-2+ P815 tumor rejection by mice in which the B7-1 gene was disrupted. Finally, consistent with the importance of B7-1-expressing host APCs for the generation of tumor-eradicating immunity against B7-2+ P815 tumor cells, CD4+ T cells (not only CD8+ T cells) were found to participate in tumor-eradicating immunity against B7-2+ P815 tumor cells. Thus, in addition to eliciting tumor-eradicating immunity directly, B7-2+ P815 tumor cells elicit tumor-eradicating immunity indirectly through B7-1-expressing host APCs that present tumor-associated Ags to CD4+ T cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Illinois at Chicago, 60612, USA.
authors.forename: R N
authors.initials: RN
authors.lastname: La Motte
authors.forename: A H
authors.initials: AH
authors.lastname: Sharpe
authors.forename: J A
authors.initials: JA
authors.lastname: Bluestone
authors.forename: M B
authors.initials: MB
authors.lastname: Mokyr
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000276:immunology*; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology*; D018122:B7-1 Antigen / Q000276:immunology*; D051940:B7-2 Antigen; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005260:Female; D012515:Mast-Cell Sarcoma / Q000276:immunology* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D011993:Recombinant Fusion Proteins / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000276:immunology; D015854:Up-Regulation
chemical_list: D015703:Antigens, CD; D000951:Antigens, Neoplasm; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497965:Cd86 protein, mouse; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins