Background

IL-18 is a proinflammatory cytokine that plays an important role in NK cell activation and Th1 cell response. It is expressed as a 24 kDa precursor by endothelial and epithelial cells, keratinocytes, γδ T cells, and phagocytes. IL-18 is related to the IL-1 family in terms of both structure and function. In terms of structure, IL-18 and IL-1β share significant primary amino acid sequences and are similarly folded as all-beta pleated sheet molecules. Like IL-1β, IL-18 is synthesized as a biologically inactive precursor molecule lacking a signal peptide. In the presence of IL-1β or IL-23, IL-18 induces the antigen-independent production of IL-17 by gamma δ T cells and CD4+ T cells (11). IL-18 also promotes myeloid dendritic cell maturation and triggers neutrophil respiratory burst (12, 13). In cancer, IL-18 exhibits diverse activities including enhancing anti-tumor immunity, inhibiting or promoting angiogenesis, and promoting tumor cell metastasis.

Specifications

Protein sequence	A DNA sequence encoding the human IL-18 (NP_001553.1) was expressed with no tag
Expression Host	E. coli
QC Testing Purity	> 90 % as determined by SDS-PAGE
Activity	Measured by its ability to induce IFN-γ secretion by KG‑1 cells in the presence of TNF-α. The ED₅₀ for this effect is 5-30 ng/mL
Endotoxin Level	< 0.1 EU per 1 μg of the protein by the LAL method
Molecular Mass	Predicts a molecular mass of 18.2 kD
Formulation	Lyophilized from sterile PBS, pH 7.4. Normally 6 % mannitol are added as protectants before lyophilization
Stability & Storage	24 months at 2 ℃ to 8 ℃ in lyophilized state. 6 months at -20 ℃ under sterile conditions after reconstitution. 12 months at -80 ℃ under sterile conditions after reconstitution. Recommend to aliquot the protein into smaller quantities after reconstituting with water for injection, normal saline or PBS, and keep the diluted concentration above 100 μg/mL. Avoid repeated freeze-thaw cycles.

References

Çakır M, Tekin S, Taşlıdere A, Çakan P, Düzova H, Gül CC (2011) Protective effect of N-(p-amylcinnamoyl) anthranilic acid, phospholipase A2 enzyme inhibitor, and transient receptor potential melastatin-2 channel blocker against renal ischemia-reperfusion injury. Cell Biochem. 2018J Cell Biochem, 120(3):3822-3832.
Xu F, Sang W, Li L, He X, Wang F, Wen T, Zeng N. (2019) Protective effects of ethyl acetate extracts of Rimulus Cinnamon on systemic inflammation and lung injury in endotoxin-poisoned mice. Drug Chem Toxicol, 42(3):309-316.

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Recombinant Human IL-18 Protein

Recombinant Human IL-18 Protein_SDS

Recombinant Human IL-18 Protein-T&L