The complement system is believed to have evolved as part of the innate immune system. Accordingly, much literature considers the complement system as part of the innate immune system. However, it is actually an integral part of both the innate and the adaptive immune responses.
The complement system is composed of a roughly 30 unique proteins circulating through our bodies. These various proteins serve a variety of functions:
- Mark pathogens for other parts of the immune system
- Attract other immune cells
- Enhance the effectiveness of antibodies and promote their formation
- Directly fight viruses and bacteria by destroying their cell walls
- Weaken viruses by destroying their protective envelope
Once the complement system becomes triggered, it begins activating in a rapid chain reaction.
In general, it’s activity occurs extremely quick and can cause intense inflammation. This process must be carefully controlled by regulatory proteins, otherwise tissue damage can occur.
A balancing game
Too much complement system activation can cause damage and has been associated with a variety of degenerative diseases. But on the other hand, too little activation is associated with an increased susceptibility to infection and the development of autoimmune disease.
This section went over the basics of the complement system. Key points include:
- The complement system is composed of roughly 30 unique proteins which support both the adaptive and the innate immune response
- These proteins serve a variety of functions and are crucial to the overall functioning of the immune system
- Complement system activation must be carefully controlled and balanced, two much deviation in either way can cause a variety of complications