The activation of the complement system can be divided into three pathways depending on the order of its initiation, namely:
1. The classical pathway is to use the antigen-antibody complex as an activating agent, which mediates the activation of C3, and then activates the immune reactions of C4, C2, C3 and so on one by one, mediating the bacteriolytic-cytolytic effect.
2. The alternative pathway (bypass pathway) is activated by pathogenic microbial membrane surface substances, mainly bacterial cell wall components, such as peptidoglycan, lipopolysaccharide, etc., the primary initiating factor is C3, followed by B and D factors gradually involved in the gradual response. This pathway is also known as the second pathway, and does not depend on the generation of antibodies, when the patient is in the early stages of infection, the activation of the mechanism is visible, so as to resist external environmental interference.
3. The MBL pathway is the mannose-binding lectin (MBL) binding to bacterial initiation. Its inducer or activator is the body's inflammatory response in the acute phase of the temporal phase of protein production of MBL and bacterial mannitol residues binding to start C4 began to activate, involved in the body's role in defense.
Therefore, the initiation of the corresponding factor by different activators can mediate different activation pathways, the main function is lysogenic bacteriolytic cytolytic effect, when the body's anti-infective process, the first activation and play a role in the bypass pathway and MBL pathway. The classical pathway is activated when specific antibodies are produced.
This article is provided by Shanghai Zhonggong Education Healthcare Exam Network