The complement system is made up of a collection of proteins found in the bloodstream and is comprised of nine major complement proteins; complement C3 is one of them. The complement system is a crucial component of the cellular immune system because it kills unwanted bacteria and initiates inflammation. Within the complement system family of proteins, C3 is the most plentiful as well as most central protein, and consists of an alpha and a beta chain. The C3 activation step represents the convergence of the lectin, classical, and alternative complement activation pathways.
