Neonatal Fc Receptor Molecules (FcRn)

Applications

• FcRn-mediated antibody rescue: study and optimise the binding of novel albumin or antibody molecules to FcRn for better biotherapeutics.
• Evaluation of biologic binding to host FcRn: conjugation of some protein-based drugs to the Fc domain of IgG or serum albumin can significantly increase their half-life.
• Quality control of IgG: study FcRn/antibody or FcRn/albumin interactions during pharmacokinetic analysis of therapeutic antibodies.
• Quality control of Fc fusion proteins: pharmacokinetic analysis of Fc- or albumin-fused therapeutics.
• Improved diagnostics: reducing the circulating half-lives of certain imaging reagents may improve assay specificity and reduce possible side effects.

Immunitrack’s FcRn Reagents

Immunitrack manufactures an extensive portfolio of catalogued FcRn and β2 microglobulin (b2m) molecules representing a range of species as listed in the table below. All molecules can be supplied in enzymatically biotinylated and non-biotinylated formats. For convenience, the molecules contain a BirA enzyme substrate peptide (BSP tag), allowing end users to easily carry out their own biotinylation step if desired.

These reagents have been successfully tested for compatibility on the following platforms: AlphaScreen (PerkinElmer), Octet (ForteBio) and Biacore (GE Healthcare). See Octet Application Note ▸  See Biacore Application Note ▸

Optimised Manufacturing Platform

Immunitrack has optimised the production of FcRn molecules in E. coli. For expression purposes, unpaired cysteines are mutated to serines. This does not affect the ligand binding characteristics of the resulting FcRn molecules. Molecules also contain a BirA enzyme substrate peptide (BSP tag) for biotinylation.

95-100% Active

Immunitrack’s FcRn molecules are bound and eluted from IgG columns in a pH-dependent way to ensure that the FcRn molecules are fully active. The molecules can be supplied in enzymatically biotinylated and non-biotinylated formats. We also have the capacity to produce active FcRn in bulk quantities for customised projects (10-30 mg).

Product Information

• Storage Buffer: PBS pH 7.5, 50 % glycerol.
• Concentration: 1 mg/mL. Determined by absorbance at 280 nm and SDS-PAGE gel densitometry using a BSA standard series (400 μg/mL, 200 μg/mL, and 100 μg/mL).
• Size: 400 µg and 1 mg aliquots.
• Stabilisers and Preservatives: None.
• Storage: Store vial at -20° C prior to opening. Dilute only prior to immediate use.
• Expiration: 6 months from date of opening.

Key Publications

1. Kræmmer Schelde et al., A new class of recombinant human albumin with multiple surface thiols exhibit stable conjugation, and enhanced FcRn binding and blood circulation. J Biol Chem. 2019 Mar 8;294(10):3735-3743
2. Grevys A et al., A human endothelial cell based recycling assay for screening of FcRn. Nat Commun. 2018 Feb 12;9(1):621.
3. Ulrichts et al., Neonatal Fc receptor antagonist efgartigimod safely and sustainably reduces IgGs in humans. J Clin Invest. 2018 Oct 1; 128(10): 4372–4386.
4. Burkrinski et al., Glucagon-like Peptide 1 Conjugated to Recombinant Human Serum Albumin Variants with Modified Neonatal Fc Receptor Binding Properties. Impact on Molecular Structure and Half-Life. Biochemistry. 2017 Sep 12;56(36):4860-4870

Go to full list of FcRn Publications ▸