Cobra Venom Factor: The Unique Component of Cobra Venom That Activates the Complement System

Abstract

Cobra venom factor (CVF) is an unusual venom component in the venom of many elapid snakes. Although CVF occurs in venom, it is not a toxin but a protein component of venom that facilitates the entry of the toxic venom components into the bloodstream by inducing complement activation at the site of envenomation. This manuscript reviews the structure of CVF and how it interacts with the complement system. The high degree of structural and functional homology of CVF to complement component C3 is described. The review also describes recombinant CVF. CVF has been used for over four decades as a research tool to deplete serum complement in animals in order to delineate the biological functions of the complement system and its role in the pathogenesis of many diseases. CVF has also been used as an experimental tool to target complement activation. Lastly, CVF has served as a lead substance for the generation of human C3 derivatives with CVF-like functions as an experimental therapeutic for complement depletion in diseases with complement pathogenesis (humanized CVF).