Importance of FC Domain in Vivo

The IgG Fc domain (constant) of an antibody determines its binding properties to Fc gamma receptors (FcγR, FcR) and complement factors (C1q). Changing antibody subtype may therefore mediate downstream effector function, summarised in part in Table 1 for human and mouse IgG subtyoes. For example, human IgG1 displays high antibody dependent cell-mediated cytotoxicity (ADCC) and complement-dependant cytotoxicity (CDC), and is the most suitable subtype for cytotoxic therapeutic use. Where cytotoxicity is not desirable, IgG2 and IgG4 antibodies would be preferable.

Table 1: IgG subtype variation in effector functions, ranked in decreasing potency.

IgG Subtypes: There are four IgG subtypes in human (IgG1, IgG2, IgG3, IgG4), mouse (IgG1, IgG2a, IgG2b, IgG3) and rat (IgG1, IgG2a, IgG2b, IgG2c). IgG subtypes exhibit high sequence homology but unique FcγR and the C1q binding profiles.

Information compiled from : Schumaker et al. (1976) PMID: 990273; Burton (1984) PMID: 3889592; Unkeless et al. (1988) PMID: 2968084; Bruggemann et al. (1989) PMID: 3500259; Bindon et al. (1988) PMID: 3260935; Niwa et al. (2005) PMID: 16219319; Natsume et al. (2008) PMID: 18483271

Customization services offered by United States Biological

• IgG subtype switching
  Replacing Fc domain of antibody whilst maintaining the variable, antigen binding regions to tailor antibody to your specific research needs.
• Nullifying Effector Function
  Abolish binding of Fc domain to FcγR using our Fc Silent™ Fc variant, a genetically engineered Fc domain developed at Absolute Antibody (patent in progress).
• Extending the Plasma Half-life
  Mutations at the interface between the CH2 and CH3 domains can enhance IgG1 serum half-life in vivo. At Absolute Antibody we can facilitate your research tailoring the plasma half-life of any of our catalogue antibodies or an antibody based on sequences provided by customers.
• Species Switching
  Our chimeric antibodies (cAbs) made by fusing the antigen binding regions from one species like mouse, with the constant domain (effector region) from another species such as a rat to increase compatibility of reagents between species and reduce unwanted immune reactions.
• Fc-fusion Proteins
  Customers may also be interested in our range of Fc fusion proteins for in vivo research.

For a more complete and detail product listing, click below:

• Antibodies