Search results
Results from the WOW.Com Content Network
Scheme of the complement system. The complement system, also known as complement cascade, is a part of the humoral, innate immune system and enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. [1]
Complement-dependent cytotoxicity (CDC) is an effector function of IgG and IgM antibodies.When they are bound to surface antigen on target cell (e.g. bacterial or viral infected cell), the classical complement pathway is triggered by bonding protein C1q to these antibodies, resulting in formation of a membrane attack complex (MAC) and target cell lysis.
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 . The membrane attack complex creates a pore on the target cell's membrane, inducing ...
IgM is a potent activator of the classical complement pathway, thus, AIHA involving IgM is characterized by complement-mediated opsonization and phagocytosis of RBCs as the amount of C3b deposited is sublytic. IgM also leads to phagocytosis of RBCs however, because phagocytic cells have receptors for the bound complement (rather than FcRs as in ...
The classical and alternative complement pathways. C3b is the larger of two elements formed by the cleavage of complement component 3, and is considered an important part of the innate immune system. C3b is potent in opsonization: tagging pathogens, immune complexes (antigen-antibody), and apoptotic cells for phagocytosis.
Phagocytosis (from Ancient Greek φαγεῖν (phagein) 'to eat' and κύτος (kytos) 'cell') is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is called a phagocyte.
After an antigen-antibody reaction, the immune complexes can be subject to any of a number of responses, including complement deposition, opsonization, [2] phagocytosis, or processing by proteases. Red blood cells carrying CR1 -receptors on their surface may bind C3b -coated immune complexes and transport them to phagocytes , mostly in liver ...
Complement factor H can inhibit the formation of the C3 convertase by competing with factor B for binding to C3b; [1] accelerate the decay of the C3 convertase; [2] and act as a cofactor for factor I-mediated cleavage of C3b. [3] Complement factor H preferentially binds to vertebrate cells (because of affinity for sialic acid residues ...