CD40–CD40 ligand protein–protein interaction (CD40–CD40L)

The CD40–CD40 ligand (CD40L) protein–protein interaction is a critical costimulatory pathway that mediates communication between adaptive and innate immune cells. CD40, a member of the tumor necrosis factor receptor superfamily (TNFRSF5), is primarily expressed on antigen-presenting cells such as B cells, dendritic cells, and macrophages, while its ligand, CD40L (CD154), is transiently expressed on activated T helper cells. This interaction is essential for B-cell proliferation, the formation of germinal centers, and the production of high-affinity antibodies through isotype switching. In autoimmune diseases like systemic lupus erythematosus and rheumatoid arthritis, overactivity of this axis drives pathogenic inflammation and autoantibody production. Conversely, in oncology, activating this pathway can 'license' dendritic cells to effectively prime anti-tumor T-cell responses. Therapeutic approaches include antagonistic antibodies or fusion proteins to block the interaction for treating autoimmunity and transplant rejection, as well as agonistic antibodies designed to stimulate CD40 for cancer immunotherapy.

Other names

CD40–CD154 interactionTNFRSF5–TNFSF5 interactionCD40–CD40L axisCD40–CD40 ligand costimulatory pathway

Antagonistic blockade of the CD40–CD40L interaction to inhibit costimulatory signaling in autoimmune diseases and transplantation, or agonistic activation of CD40 to enhance antigen presentation and T-cell mediated anti-tumor immunity in oncology.