• Product name

    Human IL-33 ELISA Kit
    See all IL-33 kits
  • Detection method

  • Precision

    Sample n Mean SD CV%
    Spiked Serum 3 2.7%
    Sample n Mean SD CV%
    Spiked Serum 5 3.2%
  • Sample type

    Cell culture supernatant, Serum, Plasma, Cell culture extracts
  • Assay type

    Sandwich (quantitative)
  • Sensitivity

    4.7 pg/ml
  • Range

    11.72 pg/ml - 750 pg/ml
  • Recovery

    Sample specific recovery
    Sample type Average % Range
    Serum 87 83% - 95%
    Cell culture extracts 95 92% - 100%
    Cell culture media 102 96% - 108%
    Heparin Plasma 102 97% - 110%
    EDTA Plasma 106 100% - 112%

  • Assay time

    1h 30m
  • Assay duration

    One step assay
  • Species reactivity

    Reacts with: Human
    Does not react with: Mouse
  • Product overview

    IL-33 in vitro SimpleStep ELISA® (Enzyme-Linked Immunosorbent Assay) kit is designed for the quantitative measurement of IL-33 protein in human serum, plasma, cell culture supernatants, and cell and tissue extracts.

    The SimpleStep ELISA® employs an affinity tag labeled capture antibody and a reporter conjugated detector antibody which immunocapture the sample analyte in solution. This entire complex (capture antibody/analyte/detector antibody) is in turn immobilized via immunoaffinity of an anti-tag antibody coating the well. To perform the assay, samples or standards are added to the wells, followed by the antibody mix. After incubation, the wells are washed to remove unbound material. TMB substrate is added and during incubation is catalyzed by HRP, generating blue coloration. This reaction is then stopped by addition of Stop Solution completing any color change from blue to yellow. Signal is generated proportionally to the amount of bound analyte and the intensity is measured at 450 nm. Optionally, instead of the endpoint reading, development of TMB can be recorded kinetically at 600 nm.

    IL-33 (Interleukin-33, also known as IL-1F11 or NF-HEV) is a proinflammatory cytokine member of the IL-1 family. It is widely expressed and functions by binding and signaling through the IL1RL1/ST2 receptor. IL-33 is expressed as a pro-protein; the antibodies in this kit were generated using the mature form of IL-33 (aa 109-270).


    Samples diluted in Sample Diluent 50BP - 4.7 pg/mL

    Samples diluted in Sample Diluent NS - 5.1 pg/mL

    Samples diluted in 1X Cell Extraction Buffer PTR - 4.9 pg/mL 

  • Tested applications

    Suitable for: Sandwich ELISAmore details
  • Platform

    Pre-coated microplate (12 x 8 well strips)


  • Storage instructions

    Store at +4°C. Please refer to protocols.
  • Components 1 x 96 tests
    10X Wash Buffer PT (ab206977) 1 x 20ml
    50X Cell Extraction Enhancer Solution (ab193971) 1 x 1ml
    5X Cell Extraction Buffer PTR (ab193970) 1 x 10ml
    Antibody Diluent 4BI 1 x 6ml
    10X Human IL-33 Capture Antibody 1 x 600µl
    10X Human IL-33 Detector Antibody 1 x 600µl
    Human IL-33 Lyophilized Recombinant Protein 2 vials
    Plate Seals 1 unit
    Sample Diluent 50BP 1 x 20ml
    Sample Diluent NS 1 x 50ml
    SimpleStep Pre-Coated 96-Well Microplate (ab206978) 1 unit
    Stop Solution 1 x 12ml
    TMB Development Solution 1 x 12ml
  • Research areas

  • Function

    Cytokine that binds to and signals through the IL1RL1/ST2 receptor which in turn activates NF-kappa-B and MAPK signaling pathways in target cells (PubMed:16286016). Involved in the maturation of Th2 cells inducing the secretion of T-helper type 2-associated cytokines. Also involved in activation of mast cells, basophils, eosinophils and natural killer cells. Acts as a chemoattractant for Th2 cells, and may function as an "alarmin", that amplifies immune responses during tissue injury (PubMed:17853410, PubMed:18836528).
    In quiescent endothelia the uncleaved form is constitutively and abundantly expressed, and acts as a chromatin-associated nuclear factor with transcriptional repressor properties, it may sequester nuclear NF-kappaB/RELA, lowering expression of its targets (PubMed:21734074). This form is rapidely lost upon angiogenic or proinflammatory activation (PubMed:18787100).
  • Tissue specificity

    Expressed at high level in high endothelial venules found in tonsils, Peyer patches and mesenteric lymph nodes. Almost undetectable in placenta.
  • Sequence similarities

    Belongs to the IL-1 family. Highly divergent.
  • Domain

    The homeodomain-like HTH domain mediates nuclear localization and heterochromatin association.
  • Post-translational

    The full length protein can be released from cells and is able to signal via the IL1RL1/ST2 receptor. However, proteolytic processing by CSTG/cathepsin G and ELANE/neutrophil elastase produces C-terminal peptides that are more active than the unprocessed full length protein. May also be proteolytically processed by calpains (PubMed:19596270). Proteolytic cleavage mediated by apoptotic caspases including CASP3 and CASP7 results in IL33 inactivation (PubMed:19559631). In vitro proteolytic cleavage by CASP1 was reported (PubMed:16286016) but could not be confirmed in vivo (PubMed:19465481) suggesting that IL33 is probably not a direct substrate for that caspase.
  • Cellular localization

    Nucleus. Chromosome. Cytoplasmic vesicle, secretory vesicle. Secreted. Associates with heterochromatin and mitotic chromosomes (PubMed:17185418).
  • Information by UniProt
  • Alternative names

    • C9orf26
    • DKFZp586H0523
    • DVS27
    • DVS27 related protein
    • IL 1F11
    • IL 33
    • IL-1F11
    • IL-33
    • IL1F11
    • IL33
    • IL33_HUMAN
    • Interleukin 1 family member 11
    • Interleukin 33
    • Interleukin 33 precursor
    • Interleukin-1 family member 11
    • Interleukin-33 (109-270)
    • Interleukin33
    • NF HEV
    • NF-HEV
    • NFEHEV
    • NFHEV
    • Nuclear factor for high endothelial venules
    • Nuclear factor from high endothelial venules
    • OTTHUMP00000021041
    • RP11 575C20.2
    see all
  • Database links

Associated products


Our Abpromise guarantee covers the use of ab223865 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

Application Abreviews Notes
Sandwich ELISA Use at an assay dependent concentration.


  • SimpleStep ELISA technology allows the formation of the antibody-antigen complex in one single step, reducing assay time to 90 minutes. Add samples or standards and antibody mix to wells all at once, incubate, wash, and add your final substrate. See protocol for a detailed step-by-step guide.


  • Background-subtracted data values (mean +/- SD) are graphed.

  • Background-subtracted data values (mean +/- SD) are graphed.

  • Background-subtracted data values (mean +/- SD) are graphed.

  • The concentrations of IL33 were measured in duplicates, interpolated from the IL33 standard curves and corrected for sample dilution. Undiluted samples are as follows: serum neat, plasma (heparin) neat, plasma (EDTA) neat and RPMI + 10% FBS neat. The interpolated dilution factor corrected values are plotted (mean +/- SD, n=2).

  • The concentrations of IL33 were measured in duplicate and interpolated from the IL33 standard curve and corrected for sample dilution. The interpolated dilution factor corrected values are plotted (mean +/- SD, n=2). The mean IL33 concentration was determined to be 351.5 pg/mL in PMA/LPS stimulated THP-1 cell extract and undetectable in unstimulated THP-1 cell extract (not shown).

  • THP-1 cells were cultured for 24 hours in the presence or absence of 50 ng/mL PMA and 10 µg/mL LPS. The concentrations of IL33 were measured in neat supernatant samples in quadruplicates and interpolated from the IL33 standard curve. The interpolated values are plotted (mean +/- SD, n=3). The mean IL33 concentration was determined to be 15.95 pg/mL in neat PMA/LPS stimulated THP-1 cell culture supernatant and undetectable in neat unstimulated THP-1 cell culture supernatant and RPMI media (not shown).



ab223865 has not yet been referenced specifically in any publications.

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