Neonatal Fc receptors (FcRn) belong to the major histocompatibility complex (MHC) family of immune molecules. FcRn receptors are much less diverse than MHC I and MHC II molecules and they do not present antigens to the immune system. Instead, they bind IgG and albumin with high affinity at low pH, and regulate their half-life in serum as well as at mucosal surfaces. Thus, FcRn receptors play an important role in immunity by influencing the longevity of IgG.
The efficacy of IgG-based therapeutics depends to a large extent on the circulating antibody half-life, which is influenced by the interaction between the antibody and FcRn receptors. Manipulating these interactions has emerged as an attractive approach to improving the pharmacokinetics of antibody-based therapeutics as well as for Fc- or albumin-fused therapeutics i.e. by rescuing them from early degradation. The ability to measure FcRn interactions is a prerequisite to studying and eventually manipulating FcRn-mediated antibody rescue.
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 ▸
- 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.
- 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. Human FcRn-human B2M only available in 1 mg aliquots.
- Stabilisers and Preservatives: None.
- Biotinylation: All our FcRn reagents can be supplied with or without an enzymatically biotinylated C terminus.
- Storage: Store vial at -20° C prior to opening. Dilute only prior to immediate use.
- Expiration: 6 months from date of opening.
All products are shipped preservative-free in liquid form at 0 °C.
For products in stock: 2 days to US and Europe, 3-4 days for Japan.
For bulk productions: We aim to ship 4-6 weeks from ordering.
- Toschkova N. et al. Conservative pattern of interaction of bat and human IgG antibodies with FcRn. Dev Comp Immunol. 2022 Oct 20;139:104579
- Hangiu O, Compte M, Dinesen A, et al. Tumor targeted 4-1BB agonist antibody-albumin fusions with high affinity to FcRn induce anti-tumor immunity without toxicity. Iscience. 2022, 25(9):104958. DOI: 10.1016/j.isci.2022.104958. PMID: 36072551; PMCID: PMC9441337.
- Gjølberg TT, Frick R, Mester S, et al. Biophysical differences in IgG1 Fc-based therapeutics relate to their cellular handling, interaction with FcRn and plasma half-life. Communications Biology. 2022, 5(1):832. DOI: 10.1038/s42003-022-03787-x. PMID: 35982144; PMCID: PMC9388496.
- Chen, X., Schneewind, O., & Missiakas, D. Engineered human antibodies for the opsonization and killing of Staphylococcus aureus. Proceedings of the National Academy of Sciences. 2022, 119(4), e2114478119.
- Mandrup, O.A., Ong, S.C., Lykkemark, S. et al. Programmable half-life and anti-tumour effects of bispecific T-cell engager-albumin fusions with tuned FcRn affinity. Communications Biology, 2021, 310 (2021).
- Larsen M.T. et al. FcRn overexpression in human cancer drives albumin recycling and cell growth; a mechanistic basis for exploitation in targeted albumin-drug designs. Journal of Controlled Release 2020, 322:53-63.
- Van Faassen H. et al. Serum albumin‐binding VHHs with variable pH sensitivities enable tailored half‐life extension of biologics. The Faseb Journal 2020, 34(6):8155-8171.
- Hubbard J. J. et al. FcRn is a CD32a coreceptor that determines susceptibility to IgG immune complex–driven autoimmunity. J Exp Med 2020, 217(10):e20200359.
- 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
- Grevys A et al., A human endothelial cell based recycling assay for screening of FcRn. Nat Commun. 2018 Feb 12;9(1):621.
- 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.
Order reagents now
You can order reagents in our webshop here:
We also have the capacity to produce active FcRn in bulk quantities upon request (10-30 mg).
For this or any other questions, please contact us using the phone numbers listed below, or write an email to email@example.com ▸
Tel. +45 28682159