Complement C2 is a protein that in humans is encoded by the C2 gene. The protein encoded by this gene is part of the classical pathway of the complement system, acting as a multi-domain serine protease, which are a class of enzymes that cleave peptide bonds in other proteins. Deficiency of C2 has been associated with certain autoimmune diseases.
The Complement system is generated to regulate self-protection from infection. The overall Complement system is composed of protein groups that collaborate in destroying foreign invaders, which ultimately remove debris from cells and tissues. When the body detects a foreign invader, the complement system becomes activated.
This activation process involves complement component 2 protein attaching to complement component 4 protein to form the complement system. Complement component 4 is a protein involved in autoimmunity, and when this protein attaches to complement component 2, it triggers an immune response. While component 4 protein is imperative for connection recognition pathways for the antibody-antigen response, complement component 2 protein is critical for regulation of these processes.