CD137 (ILA/4-1BB), expressed by primary human monocytes, induces monocyte activation and apoptosis of B lymphocytes

• Published in: International immunology Vol. 12; no. 1; pp. 73 - 82
• Main Authors: Kienzle, Georg, von Kempis, Johannes
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.01.2000; Oxford Publishing Limited (England)
• Subjects: Antibodies, Monoclonal; Antigens, CD; Apoptosis; B-Lymphocytes - immunology; Binding, Competitive; CD137 antigen; Cells, Cultured; cellular activation; Gene Expression Regulation; human; Humans; ILA induced by lymphocyte activation; Immunologic Capping; inflammatory mediators; Interleukin-10 - metabolism; Interleukin-8 - metabolism; Monocytes - cytology; Monocytes - immunology; monocytes/macrophages; PBMC peripheral blood mononuclear cells; PI propidium iodide; Receptors, Nerve Growth Factor - metabolism; Receptors, Tumor Necrosis Factor - metabolism; Signal Transduction; TNF tumor necrosis factor; tumor necrosis factor; Tumor Necrosis Factor Receptor Superfamily, Member 9; Tumor Necrosis Factor-alpha - metabolism; TUNEL terminal deoxynucleotidyl transferase dUTP nick end-labeling
• ISSN: 0953-8178; 1460-2377
• DOI: 10.1093/intimm/12.1.73

Human CD137 is a member of the tumor necrosis factor (TNF) receptor family and the homologue of murine 4-1BB. Recent studies have demonstrated that CD137 promotes accessory T cell activation, and regulates proliferation and survival of T lymphocytes. This study reports on the expression and function of CD137 in peripheral blood monocytes. While monocytes showed constitutive expression in 10 out of 18 healthy donors, CD137 was not expressed on resting T or B lymphocytes. Immobilized antibodies to CD137 markedly induced the production of IL-8 and TNF-α protein and mRNA, and led to inhibition of IL-10 expression by primary monocytes. Furthermore, cross-linking of CD137 on monocytes resulted in an increase of B lymphocyte apoptosis mediated by direct cell–cell contact of both cell populations. In conclusion, this study identified CD137 as a new receptor involved in monocyte activation by inducing a characteristic cytokine release profile. In addition, CD137 may play a role in monocyte-dependent control of B lymphocyte survival.