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Tumor necrosis factor receptor superfamily member 5 (TNFRSF5), also known as CD40 TNFRSF5 (commonly known as CD40 and also as CDW40, p50, Bp50) is widely expressed in diverse cell types including B lymphocytes, dendritic cells, platelets, monocytes, endothelial cells, and fibroblasts. It is essential in mediating a wide variety of immune and inflammatory responses, including T cell-dependent immunoglobulin class switching, memory B cell development, and germinal center formation. Its natural immunomodulating ligand is CD40L, and a primary defect in the CD40/CD40L system is associated with X-linked hyper-IgM (XHIM) syndrome. It is also involved in tumorigenesis; CD40 expression is significantly higher in gastric carcinomas and it is associated with the lymphatic metastasis of cancer cells and their tumor node metastasis (TNM) classification. Upregulated levels of CD40/CD40L on B cells and T cells may play an important role in the immune pathogenesis of breast cancer. Consequently, the CD40/CD40L system serves as a link between tumorigenesis, atherosclerosis, and the immune system, and offers a potential target for drug therapy for related diseases, such as cancer, atherosclerosis, diabetes mellitus, and immunological rejection. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",