igg2b

IgG2b Protein, Mouse, Recombinant is expressed in HEK293 mammalian cells. The predicted molecular weight is 26.3 kDa and the accession number is P01867-2.

Protein G is a bacterial cell wall protein expressed at the cell surface of certain group C and group G Streptococcal strains. It has affinity for both Fab- and Fc-fragments of human IgG by independent and separate binding sites. Binding to the Fc region of immunoglobulins from several species by a non-immune mechanism exhibits great affinity for almost all mammalian immunoglobulin G (IgG) classes, including all human IgG subclasses (IgG1, IgG2, IgG3 and IgG4) and also rabbit, mouse, and goat IgG. Protein G bound all tested monoclonal IgG from mouse IgG1, IgG2a, and IgG3, and rat IgG2a, IgG2b, and IgG2c. In addition, polyclonal IgG from man, cow, rabbit, goat, rat, and mouse bound to protein G, whereas chicken IgG did not. Protein G has also been shown to bind human serum albumin but at a site that is structurally separated from the IgG-binding region. Protein G shows a broader range of binding to IgG subclasses than staphylococcal protein A. This applies to polyclonal IgG from cow, rat, goat, human and rabbit sources as well as several of rat and mouse monoclonal antibodies. In contrast, protein A shows stronger interaction with polyclonal IgG from human, guinea-pig, pig, dog and mouse. Both proteins interacted with same relative strength to polyclonal rabbit IgG. Protein G consists of nearly 600 amino acid residues. The carboxy-terminal half contains three immunoglobulin G (IgG)-binding domains which are referred to as domains I, II, and III or units C1, C2 and C3, each containing 55 amino acid residues with two 'spacers', of 16 amino acids, Dl and D2. Following the IgG-binding regions there is a region W, which most likely is involved in cell wall interactions. Domains in the NH2-terminal half of the protein have been found to bind human serum albumin (HSA).

Protein A is surface protein originally found in the cell wall of the bacteria Staphylococcusaureus. It is encoded by the spa gene and its regulation is controlled by DNA topology, cellular osmolarity, and a two component system called ArlS-ArlR. Protein A binds the Fc region of various mammalian IgG subclasses including: Human IgG1, IgG2, IgG3 (weakly), IgG4 Mouse IgG1 (weakly), IgG2a, IgG2b, IgG3 SPA also binds IgG from monkey, rabbit, pig, guinea pig, dog, rat and cat. It also weakly binds to streptavidin.

Immunoglobulin G (IgG) is a type of antibody composed of four peptide chains—two identical heavy chains and two identical light chains arranged in a Y-shape typical of antibody monomers.There are four IgG subclasses (IgG1, 2, 3, and 4) in humans, named in order of their abundance in serum. The IgG2a isotype was able to interact very efficiently with FcgammaR, and share approximately 64-78% amino acid sequence identity with IgG1 and IgG2b in the heavy chain constant region domains, CH1, CH2 and CH3, which cause the diffrence in the interaction with complement, NK and mast cells, induction or inhibition by specific cytokines, and ability to cross the placenta.

Mouse IgG2c is a subclass of mouse antibody IgG, it can bind FcγRIV with high affinity and the Fc loop residues of mouse IgG2c promote greater receptor-binding affinity than mouse IgG2b or human IgG1.