Properdine , or factor P , is a globular protein found in the blood serum of higher animals. It is a few proenzymes dissolved in the bloodstream that belong to the complement system , which provides innate immunity.
|, BFD, PFC, PFD, PROPERDIN, complement factor properdin, Properdin|
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Properdine is known to be involved in some specific immune responses . It plays a role in tissue inflammation , as well as in the absorption of pathogens by phagocytes . In addition, his participation in the neutralization of certain viruses is known.
As a component of the alternative complement activation pathway (otherwise known as the “properdine pathway"), it complexes with another protein, C3b , to stabilize the alternative C3 convertase (C3bBb), which then cleaves more C3.
An alternative route is antibody independent. This branch of the complement system is included mainly due to the “idle” spontaneous activation of the complement component C3, which occurs in serum constantly in micro quantities due to spontaneous hydrolysis. The value of “idle” activation is that active components, adsorbed on their own surfaces, are quickly inactivated by special inactivation factors (FOOD factor of accelerated dissociation of C3 convertase, CR1, ICD-membrane cofactor protein), which are not on the surface of foreign agents and where there are all conditions for stabilization of activated C3 and the subsequent formation of anaphylatoxins , opsonins , chemotactic factors and a membrane- attacking complex that help in the fight against pathogens.
Properdin was discovered in 1954 by Louis Pillemer at the Institute of Pathology (now the Department of Pathology at Case Western Reserve University).