The complement system was discovered a century ago as a potent defense cascade of innate immunity. After its first description, continuous experimental and clinical research was performed, and three canonical pathways of activation were established. Upon activation by traumatic or surgical tissue damage, complement reveals beneficial functions of pathogen and danger defense by sensing and clearing injured cells.
The complement system is part of the innate immune system, including complement membrane attack complex / MAC, complement component / protein, complement regulator, complement receptor, collectins and ficolins.
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