CD40 receptor (CD40) and CD40 ligand (CD154) co-stimulation pathway (CD40–CD40L pathway)

The CD40–CD40L pathway enables key co-stimulatory signaling between B cells (and other APCs) and activated T cells, crucial for immune responses. CD40, a TNF receptor superfamily member, is primarily expressed on B cells, dendritic cells, and other antigen-presenting cells. Its ligand CD40L (CD154) is a transmembrane protein highly expressed on activated CD4^+^ T cells. Their interaction drives B cell proliferation, immunoglobulin isotype switching, formation of germinal centers, and long-lived plasma/memory cells. In the tumor microenvironment, CD40–CD40L signaling controls both humoral and cellular anti-tumor immunity and can be targeted by drugs to enhance or dampen the immune response[1][2][3][4]. Dysregulation of this pathway is implicated in autoimmunity, chronic inflammation, and cancer. This pathway is a central node in orchestrating adaptive immunity and is frequently targeted in immunotherapy research and development.

Other names

CD40-CD154 pathwayCD40 ligand–CD40 axisCD40–CD40L interactionCD40–CD154 costimulation

Blockade of costimulatory ligation (prevents Th cell-dependent B cell activation, dampens T cell proliferation) Immune activation/enhancement (agonistic CD40 antibodies can activate antigen-presenting cells, promoting anti-tumor immunity) Inhibition of cytokine production or inflammatory responses