Active GMP Recombinant Human IL18 Protein

• Cat.No.: IL18-153HG
• Product Overview: Recombinant HumanIL18 protein was produced in HEK293 cell in an animal component free process under cGMP guidelines.

Specification

• Source: HEK293
• Species: Human
• Form: Lyophilized from a 0.2 m filtered solution of 20mM PBS, pH7.4, 6% mannitol.
• Bio-activity: 1.0*10^6IU
  Measured by its ability to induce IFN-gamma secretion by KG‐1 human acute myelogenous leukemia cells in the presence of TNF-alpha.
• Molecular Mass: The apparent molecular mass of recombinant Human IL18 is approximately 22 kDa in SDS-PAGE under reducing conditions.
• Protein length: Tyr37-Asp193
• AA Sequence: YFGKLESKLS VIRNLNDQVL FIDQGNRPLF EDMTDSDCRD NAPRTIFIISMYKDSQPRGM AVTISVKCEK ISTLSCENKI ISFKEMNPPD NIKDTKSDIIFFQRSVPGHD NKMQFESSSY EGYFLACEKE RDLFKLILKK EDELGDRSIMFTVQNEDVD
• Endotoxin: < 100 EU per mg of the protein as determined by the LAL method.
• Purity: > 95 % as determined by SDS-PAGE.
• Storage: Store it under sterile conditions at -20°C to -80°C. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.
• Reconstitution: Always centrifuge tubes before opening. Do not mix by vortex or pipetting.
  It is not recommended to reconstitute to a concentration >100μg/ml.
  Dissolve the lyophilized protein in ddH2O.
  Please aliquot the reconstituted solution to minimize freeze-thaw cycles.

Gene Information

• Gene Name: IL18 interleukin 18 (interferon-gamma-inducing factor) [ Homo sapiens ]
• Official Symbol: IL18
• Synonyms: IL18; interleukin 18 (interferon-gamma-inducing factor); interleukin-18; IGIF; IL 1g; IL 18; IL1F4; IL-1 gamma; iboctadekin; interleukin-1 gamma; IFN-gamma-inducing factor; IL-18; IL-1g
• Gene ID: 3606
• mRNA Refseq: NM_001243211
• Protein Refseq: NP_001230140
• MIM: 600953
• UniProt ID: Q14116

Case Study

Case 1: Paudel D, et al. Gut Microbes. 2024

The impact of dietary fibers like guar gum on gut microbiota and inflammatory bowel disease (IBD) pathogenesis is not fully understood. This study found that a guar gum-enriched diet (GuD) heightened the risk of colonic inflammation, leading to worsened colitis in mice treated with dextran sulfate sodium (DSS). This was indicated by greater weight loss, diarrhea, rectal bleeding, and colon length reduction compared to mice fed cellulose.

The GuD-fed group showed increased pro-inflammatory markers in serum and colon, and severe colonic tissue damage. Treatment with antibiotics improved colitis in the GuD-fed group, implicating gut microbiota in the exacerbation of inflammation. Reduced colonic IL-18 and tight junction markers were also observed in the GuD-fed group, but pre-treatment with recombinant IL-18 mitigated colitis.

In summary, the GuD diet led to unfavorable changes in gut microbiota, causing an accumulation of lactate and succinate, a decrease in colonic IL-18, and a weakened gut barrier, all of which increased the susceptibility to colitis.

Fig1. Colonic IL-18 assessed by ELISA.

Fig2. Percent change in body wt after supplemented with rIL-18.

Case 2: Lee KT, et al. Aging (Albany NY). 2024

Osteoarthritis (OA) is recognized as an inflammatory joint disease with various mediators contributing to its development. Interleukin (IL)-18 is a cytokine significant in immune and inflammatory conditions, while IL-17, produced mainly by Th17 cells, is linked to OA though its specific role remains undefined.

In this study, researchers compared IL-18 expression in synovial tissues from healthy individuals and OA patients using immunohistochemistry (IHC). OA synovial fibroblasts (OASFs) were treated with recombinant IL-17, and IL-18 levels were measured by Western blot, qPCR, and ELISA. They utilized chemical inhibitors and siRNAs to explore the signaling pathways involved in IL-17-induced IL-18 expression and bioinformatic tools miRWalk and miRDB to identify microRNAs affecting IL-18 levels, confirmed by qPCR.

The results showed higher IL-18 expression in OA patient tissues and OASFs from severely affected rats. IL-17 was found to enhance IL-18 production in a dose-dependent manner in OASFs. The MEK/ERK/miR-4492 pathway was identified as a key driver of IL-18 production in response to IL-17, providing new insights into the molecular mechanisms of OA progression.

Fig1. OASFs were transfected with IL-18 siRNA then incubated with IL-17 for 24 h and assessed for IL-18 expression.

Fig2. IL-18 production was examined by ELISA.

Application

IL-18 is a member of the IL-1 family, and its function is mainly achieved by binding to the IL-18 receptor (IL-18R). IL-18 plays a role in a variety of inflammatory diseases, including influenza virus infection, atherosclerosis, myocardial infarction, chronic obstructive pulmonary disease, or Crohn's disease.

IL-18 can enhance anti-tumor immune response and has potential applications in cancer immunotherapy by promoting IFN-γ production and cytotoxic activity of CD8+ T cells and NK cells. IL-18 and its mutants have potential applications in drug development, such as enhancing biological activity through site-specific mutations or reducing neutralization with IL-18-binding proteins. IL-18 binding protein (IL-18BP), as a secretory immune checkpoint, may become a barrier to IL-18 immunotherapy and has potential implications for cancer therapy.

Fig1. Schematic overview of cellular IL-18/IL-18R signaling in chronic pain. (Jie Ju, 2024)

Reviews

10/15/2022

Effective in inflammation models.

08/22/2021

High stability in serum.

05/09/2019

Suitable for ELISA.

Q&As

How do researchers experimentally investigate the crosstalk between IL18 and other immune signaling pathways, such as Toll-like receptor signaling?

Co-immunoprecipitation, co-localization studies, and pathway inhibition assays decipher IL18's interactions with signaling molecules and pathways.

What assays and methodologies are employed to evaluate the potential therapeutic interventions targeting IL18 in autoimmune diseases and chronic inflammation?

Therapeutic antibody trials, in vitro drug screens, and disease model assessments assess IL18-targeted interventions in autoimmune diseases.

How are animal models and in vivo imaging techniques used to understand the kinetics of IL18-mediated immune responses and its tissue-specific effects?

Xenograft models, intravital imaging, and tissue-specific knockout approaches unravel IL18's kinetics and effects within complex in vivo environments.

Can you elaborate on the techniques used to assess the impact of IL18 on immune cell activation, migration, and effector functions?

Flow cytometry, chemotaxis assays, and functional cell assays examine IL18's impact on immune cell activation, migration, and effector functions.

Can you explain the experimental strategies used to analyze the interactions between IL18 and its receptor complex, as well as the downstream signaling events triggered by receptor engagement?

Surface plasmon resonance, mutational studies, and phosphoproteomics illuminate IL18's receptor interactions and downstream signal transduction pathways.

How are cellular and molecular techniques employed to investigate IL18's role in regulating the balance between Th1 and Th2 immune responses?

Immunophenotyping, cytokine profiling, and gene expression analyses elucidate IL18's influence on Th cell polarization and immune balance.

What experimental approaches are utilized to study the genetic and epigenetic regulation of IL18 expression in response to different stimuli?

ChIP assays, promoter analyses, and epigenetic profiling uncover the regulatory mechanisms underlying IL18 gene expression dynamics.

What methods are used to dissect the mechanisms through which IL18 contributes to the pathogenesis of inflammatory diseases and its interactions with other proinflammatory molecules?

Disease models, knockout mice, and co-stimulation studies explore IL18's involvement in inflammatory conditions and its interplay with other proinflammatory mediators.

How do researchers investigate the role of IL18 in modulating the tumor microenvironment and its potential implications for cancer immunotherapy?

Tumor models, immune profiling, and immunotherapeutic studies investigate IL18's modulation of the tumor microenvironment and its implications for cancer therapy.

Could you explain the experimental strategies used to characterize the inflammasome activation triggered by IL18 and its downstream effects on cytokine production?

Caspase assays, cytokine ELISAs, and microscopy techniques unveil the activation of inflammasomes and IL18's contribution to pyroptosis and cytokine storms.