Classical complement pathway

The Classical Complement Pathway is a component of the innate immune system. The innate immune system serves as a constant non-specific defense against foreign pathogens including bacteria, viruses, fungi, and parasites. Complement is a part of that system but it cannot act independently. Classical complement as discussed here relies on the actions of B cells to produce antibodies specific to different pathogens, as well as other components of the innate immune system such as Mast cells or Macrophages. It is an important aspect of our immune system and malfunction of complement can result in a compromised immune system. Complement deficiency has also been linked with autoimmune diseases and immunosuppression. Without complement we are unable to utilize the full strength of our immune system as macrophages and mast cells rely on it to phagocytose and release histamine respectively. While both of these cells are capable of functioning independently, the signal amplification that complement provides greatly increases their effectiveness.