CD40 is a part of the tumor necrosis factor (TNF) receptor superfamily. When bound to it’s main ligand CD40L, also known as CD154, CD40-CD40L interaction initializes the activation and proliferation of B lymphocytes or results in carcinoma cells apoptosis. CD40 can be expressed on many different cell surfaces such as endothelial cells, fibroblasts, hematopoietic progenitors, platelets, and basal epithelial cells. When combined with the variety of environments CD40 presenting cells can be in, the differing effects resulting from CD40 signalling is vast. However, one characteristic all CD40 mediated signalling has in common is that instead of using kinase to mediate signal transduction, signalling is performed through downstream adapter molecules. Some pathways activated by CD40-CD40L signalling include the activation of nuclear factor-κB, p38 mitogen activated protein kinase, c-Jun-NH2-kinase, signal transducers and activators of transcription, and phosphoinositide 3-kinase pathways. All of which ultimately help regulate alterations in gene expression.

CD40L Signalling Pathway References