Complement factor properdin (CFP)

Complement factor properdin (abbreviated CFP) is a positive regulatory glycoprotein in the alternative pathway of the complement system, essential for innate immune defense and inflammatory processes[1][2][3][6]. Properdin functions primarily by binding to C3b and C3/C5 convertase complexes on microbial surfaces or apoptotic cells, stabilizing these protease complexes and promoting rapid amplification of complement activation and opsonization[1][2][3][4]. It is unique among complement components for its role in *upregulating* (rather than downregulating) complement activity, and its deficiency leads to pronounced susceptibility to meningococcal and other infections[2][3]. Properdin is produced mainly by neutrophils and is present in plasma as an oligomeric protein, functioning as both a pattern-recognition molecule and a key modulator of complement-driven immunity, inflammation, and tissue homeostasis[3][7]. Therapeutic targeting of properdin is under investigation for complement-mediated diseases, but carries the risk of compromising host defense.

Other names

ProperdinCFPPFCComplement factor PBFDPFDcomplement factor Pproperdin P factorcomplementPROPERDIN

Inhibition of CFP blocks stabilization of C3/C5 convertases, thereby dampening alternative pathway activation and downstream complement effects[5] Potential for selective suppression of complement amplification in disease states by antagonism of CFP[3][5]