Detects feline IL-18/IL-1F4 in direct ELISAs and Western blots. In direct ELISAs, approximately 50% cross-reactivity with recombinant canine IL-18, approximately 30% cross-reactivity with recombinant porcine IL-18, approximately 20% cross-reactivity with recombinant human IL-18 and recombinant rat IL-18, and less than 10% cross-reactivity with recombinant mouse IL-18 and recombinant rhesus macaque IL-18 is observed.
Polyclonal Sheep IgG
E. coli-derived recombinant feline IL-18/IL-1F4 Tyr36-Asn192 Accession # Q95M33
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 the KG‑1 human acute myelogenous leukemia cell line. Novick, D. et al. (1999) Immunity 10(1):127. The Neutralization Dose (ND50) is typically 2‑12 µg/mL in the presence of 1 µg/mL Recombinant Rhesus Macaque IL‑18/IL‑1F4 and 20 ng/mL Recombinant Human TNF‑ alpha.
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 Feline IL‑18/IL‑1F Antibody.
In the presence of Recombinant Human TNF‑ alpha (Catalog # 210‑TA), Recombinant Feline IL‑18/IL‑1F4 (Catalog # 5989‑RM) stimulates IFN‑ gamma secretion in the KG‑1 human acute myelogenous leukemia cell line in a dose-dependent manner (orange line), as measured by the Human IFN‑ gamma Quantikine ELISA Kit (Catalog # DIF50). Under these conditions, IFN‑ gamma secretion elicited by Recombinant Feline IL‑18/IL‑1F4 (1 µg/mL) is neutralized (green line) by increasing concentrations of Sheep Anti-Feline IL‑18/IL‑1F4 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF5989). The ND50 is typically 2‑12 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). Feline IL-18 is synthesized as a 24 kDa proprotein that contains a 35 amino acid (aa) propeptide and a 157 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 feline IL-18 shares 87%-89% aa sequence identity with canine and porcine IL-18 and 62%-77% with human, mouse, rat, and rhesus 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, 11, 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).
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