Tumor necrosis factor receptor superfamily member 5 (CD40) (CD40)

Human CD40, also known as Tumor Necrosis Factor Receptor Superfamily Member 5 (TNFRSF5), is a 40-45 kDa type I transmembrane glycoprotein that serves as a critical costimulatory receptor in the immune system [1, 3]. It is constitutively expressed on antigen-presenting cells (APCs) such as B cells, dendritic cells, and macrophages, and its expression can be induced on endothelial cells, fibroblasts, and various tumor cells [6, 11]. The primary ligand for CD40 is CD40L (CD154), which is transiently expressed on activated T cells; their interaction is essential for B-cell proliferation, antibody isotype switching, and the 'licensing' of dendritic cells to initiate robust T-cell-mediated immune responses [2, 4]. In the context of oncology, CD40 is a major target for agonistic monoclonal antibodies designed to stimulate anti-tumor immunity by activating APCs and converting 'cold' tumors into 'hot' ones [8, 19]. Conversely, CD40 antagonists are being investigated for the treatment of autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis, where they aim to block the pathological overactivation of the CD40-CD40L pathway [1, 15]. Clinical development of CD40-targeted therapies faces challenges such as systemic cytokine release syndrome and hepatotoxicity, necessitating careful optimization of dosing and combination strategies [8, 14].

Other names

B-cell surface antigen CD40CD40L receptorTNFRSF5CDw40Bp50

CD40 targeted therapies function as either agonists or antagonists. Agonistic monoclonal antibodies mimic the natural ligand CD40L to activate antigen-presenting cells, enhancing anti-tumor T-cell responses and pro-inflammatory cytokine production [1, 4, 8]. Antagonistic antibodies or pathway blockers inhibit the CD40-CD40L interaction to suppress overactive B-cell and T-cell responses in autoimmune and inflammatory conditions [1, 6, 15].