C3 and infection: The N-terminal 77 amino acid split product C3a has a short half-life and is termed anaphylatoxin (Haas & Van Strijp, 2007; Pasupuleti et al., 2007) because of its mediatory function in various infections and inflammatory diseases (Thurman et al., 2007) via its specific C3a receptor (C3aR) (Humbles et al., 2000).