Purified anti-complement C3b/i

Purified anti-complement C3b/iC3b Antibody
3E7/C3b
Catalog# / Size 846102 / 100 µg
Clone
Regulatory Status RUO
Other Names Complement Component 3, C3b, iC3b, C3bi
Isotype Mouse IgG1, κ
Description Complement C3 is a 185 kD glycoprotein composed of two chains linked by a disulfide bond. It
is the fourth complement component to react in the classical pathway. It is also a key protein in
both the alternative and the lectin complement activation pathways. C3b is proteolytically
generated from C3 by cleavage of the C3a-C3b peptide bond in the protein by C3 convertase.
C3b can bind covalently, via its reactive thioester, to cell surface carbohydrates or immune
aggregates. Macrophages and neutrophils recognize C3b by the complement receptor 1
(CR1, CD35). Opsonization of target surfaces with C3b is central to all three pathways of
complement activation. The proteolytically inactive forms of C3b, iC3b, are generated by
cleavage of the alpha chain at one or two positions by factor I in the presence of co-factors,
such as factor H. A fragment of C3b, C3f, with a molecular weight of approximately 2 kD is
generated when C3b is cleaved at two positions by factor I. Although iC3b is less active than
C3b, iC3b’s interactions with lymphoid and phagocytic cells via CR2 (CD21) and CR3
(CD11b/CD18) can expand target-specific B and T cells. iC3b can be cleaved to form C3c and
C3dg.