How is the complement system regulated?

In the absence of any regulatory mechanism, the complement system has the potential to cause severe damage to host tissues. Complement control proteins, which include various plasma and cell membrane proteins, are responsible for regulating complement activation and restricting the complement pathway by inhibiting different steps in the cascade. For example, some complement control proteins halt the progression of the complement cascade, while others that are present on self-cell membranes protect self-cells from being targeted by complement.