Non-Cobra Venom Factor Venom Components Acting on Complement Proteins

The complement system, one of the first lines of defense of the innate immunity, is an important mechanism by which the body recognizes foreign substances and pathogens. This system consists of over 35 proteins, among them regulators and membrane-bound receptors and plasma proteins that interact with multiple cells and mediators of the immune system. These interactions vary according to the pathophysiologic context and occur at different stages of the immune reaction. Snake venoms contain potent cocktails of proteolytic enzymes, and the possibilities of these enzymes to interact with the complement system by either activating it or inhibiting have been investigated in many studies. The activation of the complement system by snake venoms, by generation of the potent anaphylatoxin C5a, could help the spread of the other toxic components and thereby enhancing the immobilization of the prey. Discovery of snake components that interact with the complement system may elucidate more about how the venom of snakes is spread in their prey, as well as the role of this interaction on the pathogenesis of the envenomations. It may also lead to discovery of components that aids the studies of the roles of complement in health and disease and also may yield novel anticomplement therapeutic agents. This review summarizes the key contributions regarding the action of snake venom toxins on the complement system.