Description: This antibody recognizes human complement component 3d (C3d). C3d is involved in the regulation of many aspects of the immune response including antigen processing and presentation. The C3d/antigen complex mediates B cell activation.
Description: This antibody recognizes human complement component 4d (C4d). Activation of the classical complement pathway begins with binding of an activating substance to the C1 molecule, which activates the C1 sub-units, resulting in cleavage of C4 to C4b releasing C4a in the process. The short-lived C4b molecule can bind covalently to membranes. This process is limited to the immediate vicinity of the C1 complex. Because of the short life of the C4b molecule much of the C4d is free and circulates in serum.