Detects rat IL‑18/IL-1F4 in direct ELISAs and Western blots. In Western blots, approximately 35% cross-reactivity with recombinant mouse IL‑18 is observed and approximately 10% cross-reactivity with recombinant human IL‑18 is observed.
Polyclonal Goat IgG
E. coli-derived recombinant rat IL‑18/IL-1F4 His37-Ser194 Accession # P97636
Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied as a 0.2 µm filtered solution in PBS.
<0.10 EU per 1 μg of the antibody by the LAL method.
Measured by its ability to neutralize IL‑18/IL‑1F4-induced IFN‑ gamma secretion in activated mouse T cells [Ahn, H.J. et al. (1997) J. Immunol. 159:2125]. The Neutralization Dose (ND50) is typically 1-3 µg/mL in the presence of 15 ng/mL Recombinant Rat IL‑18/IL‑1F4 and 0.1 ng/mL Recombinant Mouse IL‑12.
Please Note: Optimal dilutions should be determined by each laboratory for each application. General Protocols are available in the Technical Information section on our website.
IFN‑ gamma Secretion Induced by IL‑18/IL‑1F4 and Neutralization by Rat IL‑18/IL‑1F4 Antibody. In the presence of Recombinant Mouse IL‑12 (0.1 ng/mL, Catalog # 419‑ML), Recombinant Rat IL‑18/IL‑1F4 (Catalog # 521‑RL) stimulates IFN‑ gamma secretion in activated mouse T cells in a dose-dependent manner (orange line), as measured by the Mouse IFN‑ gamma Quantikine ELISA Kit (Catalog # MIF00). Under these conditions, IFN‑ gamma secretion elicited by Recombinant Rat IL‑18/IL‑1F4 (15 ng/mL) is neutralized (green line) by increasing concentrations of Rat IL‑18/IL‑1F4 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF521). The ND50 is typically 1-3 µg/mL.
Preparation and Storage
Reconstitute at 0.2 mg/mL in sterile PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C
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.
6 months, -20 to -70 °C under sterile conditions after reconstitution.
Interleukin-18 (IL-18), also known as IL-1F4 and IFN-gamma inducing factor (IGIF), is a member of the IL-1 family of cytokines and is a key molecule in the innate immune response (1). Rat IL-18 is synthesized as a 24 kDa proprotein that contains a 36 amino acid (aa) propeptide and a 158 aa mature region (2). Under inflammatory conditions, the propeptide is cleaved by Caspase-1 in the cytoplasm to liberate the mature nonglycosylated 18 kDa monomeric IL-18 (3, 4). Mature rat IL-18 shares 91% aa sequence identity with mouse IL-18 and 60-64% aa sequence identity with human, canine, feline, porcine, and rhesus macaque IL-18. IL-18 is secreted by a variety of cell types including macrophages, dendritic cells, and epithelial cells (1, 5). Circulating mature IL-18 is sequestered by soluble IL-18 binding proteins (IL-18 BP) that inhibit IL-18 bioactivity (6). IL-18 interacts with the widely expressed IL-18 R alpha which then recruits the signaling subunit IL-18 R beta (7, 8). The IL-1 family member IL-1F7 also binds to IL-18 R alpha but does not recruit IL-18 R beta or induce signaling (9). IL-1F7 binds IL-18 BP and enhances its neutralizing effect on IL-18 activity (9). IL-18 synergizes with other cytokines to activate NK, Th1, and Th17 cells and to increase the production of IFN-gamma (1, 5, 10-12). IL-18 can also promote Th2 cytokine release which reduces the effectiveness of antiviral responses (13, 14). Increased levels of active IL-18 contribute to the severity of autoimmunity and hypertension, while deficiency of IL-18 results in symptoms of metabolic syndrome (1, 5, 15, 16). In cancer, IL-18 stimulates Th1 and NK cells to target tumor cells, but it can also promote angiogenesis, metastasis, and tumor cell immune evasion (11).
Arend, W.P. et al. (2008) Immunol. Rev. 223:20.
Culhane, A.C. et al. (1998) Mol. Psychiatry 3:362.
Ghayur, T. et al. (1997) Nature 386:619.
Gu, Y. et al. (1997) Science 275:206.
Boraschi, D. and C.A. Dinarello (2006) Eur. Cytokine Netw. 17:224.
Novick, D. et al. (1999) Immunity 10:127.
Torigoe, K. et al. (1997) J. Biol. Chem. 272:25737.
Born, T.L. et al. (1998) J. Biol. Chem. 273:29445.
Bufler, P. et al. (2002) Proc. Natl. Acad. Sci. USA 99:13723.
R&D Systems personnel manually curate a database that contains references using R&D Systems products.
The data collected includes not only links to publications in PubMed,
but also provides information about sample types, species, and experimental conditions.
Role of IL-18 in acute lung inflammation. Authors: Jordan JA, Guo RF, Yun EC, Sarma V, Warner RL, Crouch LD, Senaldi G, Ulich TR, Ward PA J. Immunol., 2001;167(12):7060-8. Species: Rat Sample Type: BALF Application: ELISA Development
Fixed with 4%Polyoxymethylene and 15%saturation picric acid. Without antigen retrieval. Frozen section, 20m, floating slice method. First antibody 4 degrees over night and secondary antibody 2 hours at room-temperature. Antigen retrieval in 99 degrees citrate buffer(pH 4.6) for 5min would benefit the output (not tested). Green: Interleukin-18; red: Iba-1 (microglia marker). Specificity: Reasonably specific Sensitivity: Reasonably sensitive Buffer: PBS Dilution: 1/100
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