CD55

CD55, also known as decay accelerating factor (DAF), is a protein that plays a crucial role in the innate immune system. It is a cell surface glycoprotein that protects cells from damage by the complement system. The complement system is a part of the immune system that helps clear pathogens and damaged cells from the body, but it can also inadvertently damage host cells. CD55 prevents this by binding to complement fragments and accelerating their decay, thereby stopping the complement cascade.

CD55 is expressed on the surface of most human cells, particularly those exposed to the external environment or at risk of complement attack, such as erythrocytes, leukocytes, and endothelial cells. Its presence on these cells is essential for preventing autoimmune reactions and maintaining tissue homeostasis.

The gene encoding CD55 is located on chromosome 1q32.1. Mutations in this gene are rare but have been associated with certain rare genetic disorders, although the primary function of CD55 is its role in complement regulation.

In addition to its protective role in the complement system, CD55 has also been implicated in other cellular processes, including cell adhesion and signal transduction. Its involvement in these diverse functions highlights its importance in maintaining cellular health and immune surveillance. Research continues to explore the full spectrum of CD55's biological activities and its potential therapeutic applications.