Recombinant Human IL-18 BPa His-tag Protein, CF

Recombinant Human IL‑18 BPa His-tag (Catalog # 11236-BP) has a molecular weight (MW) of 33.7 kDa as analyzed by SEC-MALS, suggesting that this protein is a monomer. MW may differ from predicted MW due to post-translational modifications (PTMs) present (e.g. Glycosylation).

Measured by its ability to inhibit the IL-18-induced response of KG-1 Human Acute Myelogenous Leukemia cells . The ED50 for this effect is 5.00-30.0 ng/mL in the presence of 20 ng/mL of Recombinant Human IL-18.

2 μg/lane of Recombinant Human IL-18 BPa His-tag Protein (Catalog # 11236-BP) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 44-51 kDa.

• Reactivity: Hu
• Applications: Bioactivity
• Format: Carrier-Free

Recombinant Human IL-18 BPa His-tag Protein, CF Summary

• Details of Functionality: Measured by its ability to inhibit the IL-18-induced response of KG-1 human acute myelogenous leukemia cells. The ED₅₀ for this effect is 5.00-30.0 ng/mL in the presence of 20 ng/mL of recombinant human IL-18.
• Source: Human embryonic kidney cell, HEK293-derived human IL-18 BPa protein
  Thr31-Gly194, with a C-terminal 6-His tag
• Accession #: O95998.2
• N-terminal Sequence: Thr31
• Protein/Peptide Type: Recombinant Proteins
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining
• Endotoxin Note: <0.10 EU per 1 μg of the protein by the LAL method.

Applications/Dilutions

• Dilutions:
  • Bioactivity
• Theoretical MW: 18 kDa.
  Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
• SDS-PAGE: 44-51 kDa, under reducing conditions.

Packaging, Storage & Formulations

• 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.
• Buffer: Lyophilized from a 0.2 μm filtered solution in PBS with trehalose.
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining
• Reconstitution Instructions: Reconstitute at 500 μg/mL in PBS.

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Recombinant Human IL-18 BPa His-tag Protein, CF

• IL18 BPa
• IL-18 BPa
• IL18BP
• IL-18BP
• IL18BPa
• interleukin 18 binding protein
• interleukin-18-binding protein
• MC51L-53L-54L homolog gene product
• tadekinig-alfa

Background

Interleukin 18 binding protein (IL-18 BP) is a secreted glycoprotein, which functions as an IL-18 antagonist by binding to IL-18 and blocking its biological activity. IL‑18 BP bears no amino acid sequence homology to the membrane-associated IL-18 and IL-1 receptor proteins. The gene for human IL-18 BP has been localized to chromosome 11q13. It encodes for at least four isoforms by alternative splicing. The IL-18 BP isoforms a and c each contain one immunoglobulin (Ig)-like C2-type domain while isoforms b and d lack a complete Ig domain. The complete Ig domain has been shown to be essential to the binding and neutralizing properties of the binding proteins. Two isoforms of mouse IL18 BP (c and d) containing the complete Ig domain have also been isolated and shown to neutralize IL-18 bioactivity. Human and mouse IL-18 BPs share approximately 61% amino acid sequence identity. Several poxviruses also encode proteins with sequence similarity to the human and mouse IL-18 BP. Viral IL-18 BPs have been shown to bind and inhibit IL-18 responses and may be involved in modulating host immune responses. The expression of IL-18 BP is markedly up-regulated by IFN-gamma , suggesting that IL-18 activity is modulated by a negative feedback mechanism mediated by IL-18 BP.

1. Mühl, H. et al. (2000) Biochem. Biophys. Res. Commun. 267:960.
2. Kim, S-H. et al. (2000) Proc. Nat. Acad. Sci. USA 97:1190.
3. Calderara, S. et al. (2001) Virology 279:22.

Bioinformatics

• Uniprot:
  • O95998.2()