Immunitrack’s Neonatal Fc Receptor: FcRn

Advantages at a Glance

  • Optimized manufacturing platform
  • Wide range of species options available
  • 100% active
  • Compatible with measurement of high-quality protein kinetics

Optimized Manufacturing Platform

Immunitrack has optimized the production of FcRn. We have the ability to produce active FcRn in large quantities for customized projects.

For expression purposes unpaired cysteines are mutated to serines. This does not affect the ligand binding characteristics of the FcRn molecules we produce.

The molecules are 100% active and can be enzymatically biotinylated at the C terminus of the FcRn heavy chain, allowing IgG and albumin to bind simultaneously.

SDS-PAGE gel shift assays showing the biotinylation of FcRn heavy chains, the site specific biotinylation at the C terminus ensures directed immobilization and allows simultaneous binding of albumin and IgG.

Wide Range of Species Options Available

Currently we are able to deliver FcRn molecules based on the following species, with different species combinations of b2m and FcRn.

FcRn molecules not present on the list may be synthesized and produced upon request.

b2mFcRnbiotinylatedsize (ug)

100% Active

Immunitracks FcRn molecules are 100 % active and can be supplied with or without an enzymatically biotinylated C terminus.

Compatible with measurement of high-quality protein kinetics

Immunitrack’s FcRn molecules have been tested successfully on a variety of platforms (AlphaScreen, Octet and Biacore), please see below. An application note on the Biacore platform was developed in a collaboration with GE healthcare, it can be downloaded here: FcRn Immunitrack GE collaboration

Examples of the performance of biotinylated FcRn on different protein binding kinetic assay platforms

AlphaScreen™ , Perkin Elmer

Titration of a chimeric monoclonal antibody against the human CD20 protein (black, Kd 32nM) and human serum albumin (HSA, grey, Kd 850) biotinylated human FcRn using the Alpha Screen platform from Perkin Elmer. BLI, Octet ForteBio

Octet® Platform, Fortebio

Kinetic analysis of binding of HSA and HSA K573P mutant on biotinylated human FcRn on the Octet platform from ForteBio.
Human IgG1 binds biotinylated FcRn from all species

Biacore, GE heathcare Life Sciences

Examples showing binding profiles for different types of antibodies to human, macaque and mouse FcRn. Binding behavior towards human and macaque FcRn was very similar. All antibodies showed highest binding towards mouse FcRn. Binding specificities for all antibodies were in agreement with published data (*Abdiche, Y. N. et al. 2014, mAbs, 7, 331-338). Biotin CAP Kit (GE Healthcare) was used with FcRn capture levels 90-100 RU and antibody concentration series: 25, 74, 222, 666 and 2000 nM. Running buffer: 20 mM phosphate, 150 mM NaCl, 0.05 % Surfactant P20, pH 6

More Information

The efficacy of IgG-based therapeutics could be based on the interaction between therapeutic antibody and neonatal Fc receptor (FcRn). This is one of the critical factors in determining the circulating antibody half-life. Exploiting this FcRn mediated rescue has emerged as a generalizable approach to improving the pharmacokinetics of therapeutics. The ability to measure FcRn interactions is a prerequisite for the study and eventual manipulation of FcRn mediated rescue.

Selected Publications

Materno-fetal transfer of preproinsulin through the neonatal Fc receptor prevents autoimmune diabetes.
Diabetes. 2015 Apr 27.

Regulation of immune responses to protein therapeutics by transplacental induction of T cell tolerance.
Sci Transl Med. 2015 Feb 18;7(275)

Stabilisation of the Fc fragment of human IgG1 by engineered intradomain disulfide bonds.
PLoS One. 2012;7(1):e30083.
PMID: 22272277

Ligand binding and antigenic properties of a human neon.
FEBS J. 2008 Aug;275(16):4097-110.
PMID: 18637944

A strategy for batal Fc receptor with mutation of two unpaired cysteine residues. Bacterial production of a soluble functional human neonatal Fc receptor.
J Immunol Methods. 2008 Feb 29;331(1-2):39-49.
PMID: 18155020