Tumor necrosis factor receptor superfamily member 5 (TNFRSF5) in teleosts; 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. Salmon CD40 and CD40L are widely expressed, particularly in immune tissues, and their importance for the immune response is indicated by their relatively high expression in salmon lymphoid organs and gills.
Jiyao W et al.(2023). "The conserved domain database in 2023.",