Cd47 (Cluster of Differentiation 47) is a protein that in humans is encoded by the CD47 gene.
It is also known as integrin-associated protein (IAP), membrane glycoprotein receptor 3 (MGR3), or scarlet blood cell antigen 1B4 (Sca-1). Cd47 is a ubiquitously expressed surface protein that functions as an important regulator of cellular activity. It has been implicated in a variety of cellular processes including cell adhesion, proliferation, migration, and survival.
Cd47 is a member of the immunoglobulin superfamily and contains four Ig-like domains in its extracellular region. The cytoplasmic tail of Cd47 interacts with various proteins to modulate signal transduction pathways. Cd47 is primarily found on hematopoietic cells where it functions as an “off switch” for macrophage phagocytosis. In addition to its role in innate immunity, Cd47 has also been shown to be involved in adaptive immunity. Cd47 has been shown to interact with T cells and B cells to regulate their development and function.
The exact role of Cd47 in human diseases is still being elucidated but it has been implicated in several conditions such as cancer, autoimmune disease, and transplant rejection. Cancer cells often overexpress Cd47 which confers resistance to phagocytic clearance by the immune system. This leads to unchecked tumor growth and metastasis. Autoimmune diseases are characterized by aberrant immune responses against self-antigens. Several studies have shown that Cd47 is upregulated on autoimmune target tissues and may play a role in the pathogenesis of these disorders. Finally, transplant rejection occurs when donor tissue is recognized as foreign by the recipient’s immune system leading to graft destruction. Studies have shown that expression of Cd47 on donor cells can inhibit this process and improve transplant outcomes