Complement Factor P, also known as properdin, is a protein component of the immune system that plays a crucial role in the activation and amplification of the alternative pathway of the complement system. The complement system is a part of the innate immune response and functions to enhance the ability of antibodies and phagocytic cells to clear pathogens and damaged cells from the body.
Complement Factor P is a glycoprotein that is primarily produced by specialized immune cells, such as neutrophils, monocytes, and macrophages. It circulates in the blood plasma in an inactive form and becomes activated upon recognition of foreign antigens or immune complexes.
Once activated, Complement Factor P binds to other complement proteins, forming a complex that stabilizes and enhances the activity of C3 convertase enzymes. This leads to the rapid and controlled cleavage of C3 into smaller fragments, C3a and C3b. C3b, in particular, plays a critical role in opsonization, which marks foreign particles for phagocytosis by immune cells.
Additionally, Complement Factor P acts as a bridging molecule between the complement system and other components of the immune system, such as immune cells and antibodies. This interaction promotes the recruitment and activation of immune cells, resulting in the elimination of pathogens and the initiation of an inflammatory response.
Deficiencies or dysregulation of Complement Factor P have been associated with an increased susceptibility to infections, autoimmune diseases, and inflammatory conditions. Studies are ongoing to further understand the precise roles and regulatory mechanisms of this important complement factor in immune responses.
