CD45 is a receptor-type protein tyrosine phosphatase, also known as Ly-5 or the leukocyte common antigen. It functions primarily by regulating the activation of Src family protein tyrosine kinases, such as Lck and Fyn, thereby initiating T cell receptor signaling. Deficiency in CD45 results in dysfunctional T and B lymphocytes, leading to severe combined immunodeficiency. Furthermore, CD45 plays a significant role in the pathogenesis of autoimmune diseases, cancer, and infectious diseases, including fungal infections.
