Explain with diagram regulation of classical complement pathway.
Answers
Answer by Rashid21
The classical complement pathway is one of three pathways which activate the complement system, which is part of the immune system. The classical complement pathway is initiated by antigen-antibody complexes with the antibody isotypes IgG and IgM.[1][2]
Following activation, a series of proteins are recruited to generate C3 convertase (C4b2a), which cleaves the C3 protein. The C3b component of the cleaved C3 binds to C3 convertase (C4b2a) to generate C5 convertase (C4b2a3b), which cleaves the C5 protein. The cleaved products attract phagocytes to the site of infection and tags target cells for elimination by phagocytosis. In addition, the C5 convertase initiates the terminal phase of the complement system, leading to the assembly of the membrane attack complex (MAC). The membrane attack complex creates a pore on the target cell's membrane, inducing cell lysis and death.[2][3]
The classical complement pathway can also be activated by apoptotic cells, necrotic cells, and acute phase proteins.[1][3][4]