Tumor necrosis factor receptor superfamily member 5 (CD40) and CD40 ligand (CD154) (CD40-CD40L)

CD40 (Tumor necrosis factor receptor superfamily member 5) and its ligand CD40L (CD154 or Tumor necrosis factor ligand superfamily member 5) form a critical costimulatory signaling axis that bridges innate and adaptive immunity (UniProt P25942, P29965). CD40 is primarily expressed on antigen-presenting cells such as B cells, dendritic cells, and macrophages, while CD40L is transiently expressed on activated T cells (PubMed: 25210136). The interaction between these molecules is essential for B cell activation, immunoglobulin class switching, and the formation of germinal centers, which are necessary for high-affinity antibody production (PubMed: 15123777). Beyond humoral immunity, the CD40-CD40L pathway facilitates the "licensing" of dendritic cells, enabling them to effectively prime cytotoxic T cell responses (PubMed: 28213343). Dysregulation of this axis is a hallmark of various autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis, and it also plays a role in the inflammatory components of atherosclerosis and cancer progression (PubMed: 30655458). Therapeutic development has focused on CD40L-blocking antibodies to treat autoimmunity and CD40-agonistic antibodies to enhance anti-tumor immunity, though early CD40L inhibitors were hampered by thromboembolic safety concerns (PubMed: 29101231).

Other names

TNFRSF5CD40 antigenB-cell surface antigen CD40TNFSF5CD154T-cell antigen Gp39TNF-related activation proteinTRAPHIGM1CD40LCD40 receptor

The mechanism of action involves either the antagonism of the CD40-CD40L interaction to prevent costimulatory signaling and suppress B cell-mediated immune responses in autoimmune diseases and transplant rejection, or the agonism of the CD40 receptor to activate antigen-presenting cells and enhance T cell-mediated anti-tumor immunity in oncology (PubMed: 30655458, 29101231).