They are activated in cascade upon recognition of microorganisms. They are responsible for the opsonization of pathogens that will be sent for phagocytosis (Dunkelberger, 2010). Complement is composed of three pathways: the classical, alternative, and mannose-binding lectin (MBL) pathways. Several proteins are involved in these pathways (Dunkelberger, 2010). The classical pathway is induced when the C1 protein interacts with an antibody/antigen complex. The alternative pathway is induced when the C3 protein interacts with certain bacterial components. The MBL pathway is induced when the mannose binding protein interacts with certain bacterial elements. The three pathways induce the membrane attack complex (figure