Recombinant Human IL-1 RII Fc Chimera Protein, CF

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Recombinant Human IL-1 RII Fc Chimera Protein, CF Summary

Product Specifications

>95%, by SDS-PAGE under reducing conditions and visualized by silver stain.
Endotoxin Level
<0.01 EU per 1 μg of the protein by the LAL method.
Measured by its ability to inhibit IL-1 beta -dependent proliferation in D10.G4.1 mouse helper T cells. Symons, J.A. et al. (1987) in Lymphokines and Interferons, a Practical Approach. Clemens, M.J. et al. (eds): IRL Press. 272.

Approximately 0.3-1.8 μg/mL of Recombinant Human (rh) IL‑1 RII Fc Chimera will inhibit 50% of the biological response due to 50 pg/mL of rhIL-1 beta.

Chinese Hamster Ovary cell line, CHO-derived human IL-1 RII protein
Human IL-1 RII
(His21 - Glu343)
Accession # P27930
(Pro100 - Lys330)
N-terminus C-terminus
Accession #
N-terminal Sequence
Structure / Form
Disulfide-linked homodimer
Predicted Molecular Mass
63.7 kDa (monomer)
80-95 kDa, reducing conditions

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Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.


Formulation Lyophilized from a 0.2 μm filtered solution in PBS.
Reconstitution Reconstitute at 100 μg/mL in PBS.
Shipping The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -20 to -70 °C as supplied.
  • 1 month, 2 to 8 °C under sterile conditions after reconstitution.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.
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Background: IL-1 RII

IL-1 Receptor II (also IL‑1 R2) is a 60 ‑ 70 kDa member of the interleukin‑1 receptor family of proteins (1 ‑ 4). It serves as a non‑signaling ligand‑binding decoy receptor for IL‑1 beta and IL‑1 alpha  (4). IL‑1 binds to a cell surface complex composed of IL‑1 RI and IL‑1 RAcP. Upon activation, this complex recruits MyD88 for downstream signaling (4, 5). The proinflammatory action of IL-1 is antagonized by IL‑1ra which binds to IL‑1 RI but does not initiate signaling. A second natural antagonist is IL‑1 RII, a cell surface receptor that binds both IL‑1 alpha and beta, but not IL‑1ra. IL‑1 RII is found on astrocytes, neutrophils, anterior pituitary acidophils that secrete GH, corneal epithelium, testicular Leydig and Sertoli cells, B cells and monocytes/macrophages (6 ‑ 12). Mature human IL‑1 RII is a 385 amino acid (aa) type I transmembrane glycoprotein that contains a 330 aa extracellular region with three Ig‑like domains (aa 14 ‑ 343), a 26 aa transmembrane segment, and a 29 aa cytoplasmic domain with no signaling motifs (13). There is one soluble 55 ‑ 60 kDa alternative splice form that shows a premature truncation after Gln296 (14). ARTS‑1 mediated cleavage of IL-1 RII generates a 47 kDa isoform, while alpha ‑secretase cleavage after Arg338 creates a 50 ‑ 55 kDa isoform that undergoes further processing back to Pro314 (15, 16). Human IL‑1 RII shares 59% aa identity with mouse IL‑1 RII in the extracellular region. Different forms of human IL‑1 RII demonstrate differing binding affinities for IL‑1. IL‑1 RII has a preference for IL‑1 beta over IL‑1 alpha, and binding requires the presence of IL‑1 RAcP. This interaction prevents the association of IL‑1 with IL‑1 RI and also restricts IL‑1 R to a non‑signaling receptor complex (11, 17 ‑ 19). The membrane IL‑1 RII:IL‑1 RAcP complex does not form a functional bond with IL‑1ra, and cannot bind pro‑IL‑1 beta (11, 13, 19, 20). Soluble IL‑1 RII, by contrast, demonstrates a different binding profile. Notably, it will bind pro‑IL‑1 beta rendering it unavailable for activation by extracellular proteases (19, 20). Although it will sequester both IL‑1 beta and IL‑1 alpha, its interaction with soluble IL‑1 RAcP creates a circulating high affinity complex for both IL‑1 beta and IL‑1 alpha, thus potentiating its anti‑inflammatory activity.

  1. Dinarello, C.A. (2011) Blood 117:3720.
  2. Boraschi, D. and A. Tagliabue (2006) Vitam. Horm. 74:229.
  3. Dunne, A. and L.A.J. O’Neill (2003) Sci STKE. Feb 25;2003(171):re3.
  4. Dinarello, C.A. (2009) Annu. Rev. Immunol. 27:519.
  5. O’Neill, L.A.J. (2008) Immunol. Rev. 226:10.
  6. Pousset, F. et al. (2001) J. Neurochem. 79:726.
  7. Bourke, E. et al. (2003) J. Immunol. 170:5999.
  8. French, R.A. et al. (1996) Endocrinology 137:4027.
  9. Cubitt, C.L. et al. (2001) Invest. Ophthalmol. Vis. Sci. 42:701.
  10. Gomez, E. et al. (1997) Biol. Reprod. 56:1513.
  11. Lang, D. et al. (1998) J. Immunol. 161:6871.
  12. Mantovani, A. et al. (2001) Trends Immunol. 22:328.
  13. McMahan, C.J. et al. (1991) EMBO J. 10:2821.
  14. Liu, C. et al. (1996) J. Biol. Chem. 271:20965.
  15. Cui, X. et al. (2003) J. Immunol. 171:6814.
  16. Kuhn, P-H. et al. (2007) J. Biol. Chem. 282:11982.
  17. Smith, D.E. et al. (2003) Immunity 18:87.
  18. Makinowsky, D. et al. (1998) FEBS Lett. 429:299.
  19. Neumann, D. et al. (2000) J. Immunol. 165:3350.
  20. Symons, J. A. et al. (1995) Proc. Natl. Acad. Sci. USA 92:1714.
  21. Wang, D. et al. (2010) Nat. Immunol. 11:905.
Long Name
Interleukin 1 Receptor II
Entrez Gene IDs
7850 (Human); 16178 (Mouse)
Alternate Names
beta; CD121b antigen; CD121b; IL-1 R beta; IL-1 RII; IL1R2; IL1RBCD121 antigen-like family member B; IL-1R-beta; IL1RII; IL-1RII; IL-1RT2; IL-1RT-2; interleukin 1 receptor, type II; Interleukin-1 receptor beta; MGC47725


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