Technical Articles

CD40 (also known as TNFRSF5) is a member of the tumor necrosis factor receptor superfamily, primarily expressed on antigen-presenting cells (such as dendritic cells and B cells). Its ligand, CD40L (also known as CD154 or TNFSF5), is mainly expressed on the surface of activated T cells. The interaction between CD40 and CD40L serves as a critical co-stimulatory signal in T cell-dependent immune responses, playing a vital role in B cell activation, antibody class switching, dendritic cell maturation, and the activation of cellular immunity.