A member of the Tumor Necrosis Factor Receptor superfamily with specificity for CD40 Ligand. It is found on mature B-Lymphocytes and some Epithelial Cells, lymphoid Dendritic Cells. Evidence suggests that CD40-dependent activation of B-Cells is important for Generation of Memory B-Cells within the Germinal Centers. Mutations of the Gene for CD40 Antigen result in Hyper-IgM Immunodeficiency Syndrome, Type 3. Signaling of the receptor occurs through its Association with TNF Receptor-Associated Factors.