How are complement proteins produced?

When triggered by specific stimuli, proteases (zymogens) cleave off the complement system proteins, setting off a cascade of reactions. This cascade results in the release of cytokines, inducing a series of amplifying cleavages. Ultimately, the complement activation leads to the stimulation of phagocytes, enabling the elimination of foreign and damaged substances, activating the membrane attack complex, and inducing inflammation to attract more phagocytes. This system comprises approximately 50 proteins and protein fragments, including those found in the blood serum and on cell membranes. Together, they make up approximately 10% of the globulin fraction in blood serum.