Complement receptor (CR) 1, 3, and 4 function as opsonins which stimulate phagocytosis, whereas CR2 is expressed only on B cells as a co-receptor. Red blood cells (RBCs) also express CR1, which enables RBCs to carry complement-bound antigen-antibody complexes to the liver and spleen for degradation.

2022年9月15日 · Complement 3 (C3)-knockout attenuates right ventricular dysfunction and fibrosis in a mouse model of right ventricular failure. C3a is produced from C3 by the C3 convertase complex, which...

Complement receptors recognize either the C3 proteolytically activated fragments C3b, iC3b, and C3dg deposited on opsonized surfaces (CR1 to CR4 and CRIg) or the soluble anaphylatoxins released during alternative pathway activation (C3aR) or terminal pathway activation (C5aR1/C5aR2).

2022年1月1日 · As the most abundant component of the complement system, C3 and its proteolytic derivatives serve essential roles in the function of all three complement pathways. Central to this is a network of protein-protein interactions made possible by the sequential proteolysis and far-reaching structural changes that accompany C3 activation.

As the most abundant component of the complement system, C3 and its proteolytic derivatives serve essential roles in the function of all three complement pathways. Central to this is a network of protein-protein interactions made possible by the sequential proteolysis and far-reaching structural changes that accompany C3 activation.

Besides the direct killing of antibody-coated tumor cells by complement-dependent cytotoxicity (CDC), mediated by the MAC, complement can also opsonize tumor cells and facilitate cellular cytotoxicity upon engagement of bound C3 fragments with C3 receptors on NK cells and leukocytes (Klein et al., 1990; Ross, 2000; van Lookeren Campagne et al ...

Complement Component C3 Receptor, also known as CR2 or CD21, is a glycoprotein receptor that binds to iC3b, C3d, and C3dg. It plays a crucial role in B cell activation by lowering the threshold of antibody stimulation required for activation and promoting B cell memory development by facilitating antigen display and survival signals.

The availability of polyclonal and monoclonal antibodies to C3 receptors allowed more accurate studies of the cellular distribution of these receptors. Finally, advances in our knowledge of the functional properties of the C3 receptors and their relationship to specific cell surface molecules was facilitated by recognition of a patient ...

In our review, we look at the complement system as an archetype of a preformed mediator of host defense and show how nature industriously and elegantly uses a single molecular scaffold, i.e. complement component C3, to achieve exceptional versatility in coordinating defense responses.

We will proceed by describing the C3a interaction with the anaphylatoxin receptor, followed by the interactions of opsonins (C3b, iC3b, and C3dg/C3d) with complement receptors, divided into two groups: receptors bearing complement regulatory functions and the effector receptors without complement regulatory activity.