title: Monoclonal antibodies directed against the T-cell activation molecule CD137 (interleukin-A or 4-1BB) block human lymphocyte-mediated suppression of tumor xenografts in severe combined immunodeficient mice.
abstract: A monoclonal antibody specific for the human analog of the murine T-cell activation molecule 4-1BB was generated and is shown here to react selectively with activated human CD4+ and CD8+ T lymphocytes. Treatment of these T cells in a one-way mixed lymphocyte culture with the anti-h4-1BB antibody enhanced the cell proliferation of the allostimulated lymphocytes. Previous studies in the mouse have shown that treatment of tumor-bearing mice with antibodies to 4-1BB augments anti-tumor immunity that is mediated by both CD4+ and CD8+ T cells. The authors consider the possibility that a similar approach may be efficacious for human cancer immunotherapy. This question was addressed by evaluating the effect of an anti-h4-1BB monoclonal antibody on human lymphocyte-mediated suppression of a human tumor xenograft in SCID mice. Mice treated with a control antibody and co-injected with the tumor and peripheral blood lymphocytes exhibited a lymphocyte dose-dependent suppression of tumor growth. In mice treated with the anti-h4-1BB antibody, the lymphocyte-mediated tumor suppression was completely eliminated and tumors grew progressively (as was observed in mice inoculated with tumors without lymphocytes). This monoclonal antibody specific for anti-h4-1BB, which augments the proliferation of allostimulated cells in vitro, blocks T-cell anti-tumor activity in vivo. These results suggest that although 4-1BB plays a role in the human peripheral blood lymphocyte-mediated suppression of tumor growth, antibodies to this molecule on human cells fail to stimulate anti-tumor activity, as was observed in tumor-bearing mice treated with an antibody to murine 4-1BB.
authors.affiliation: Department of Immunology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Sabel
authors.forename: T F
authors.initials: TF
authors.lastname: Conway
authors.forename: F A
authors.initials: FA
authors.lastname: Chen
authors.forename: R B
authors.initials: RB
authors.lastname: Bankert
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD; D015704:CD4 Antigens / Q000276:immunology; D016827:CD8 Antigens / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D006801:Humans; D007519:Isoantigens / Q000276:immunology; D008175:Lung Neoplasms / Q000276:immunology*; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D009368:Neoplasm Transplantation; D017475:Receptors, Nerve Growth Factor / Q000276:immunology*; D018124:Receptors, Tumor Necrosis Factor / Q000276:immunology*; D016511:Severe Combined Immunodeficiency / Q000276:immunology*; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015704:CD4 Antigens; D016827:CD8 Antigens; D007519:Isoantigens; D017475:Receptors, Nerve Growth Factor; D018124:Receptors, Tumor Necrosis Factor; C505714:TNFRSF9 protein, human; C505715:Tnfrsf9 protein, mouse; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9