Anti-Interferon regulatory factor 9 / IRF-9 antibody (ab51639)




Our Abpromise guarantee covers the use of ab51639 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
ICC/IF Use a concentration of 1 µg/ml.
WB Use a concentration of 1 - 5 µg/ml. Predicted molecular weight: 44 kDa. Good results were obtained when blocked with 5% non-fat dry milk in 0.05% PBS-T.
IHC-P Use a concentration of 4 - 8 µg/ml.


  • Function
    Transcription regulatory factor that mediates signaling by type I IFNs (IFN-alpha and IFN-beta). Following type I IFN binding to cell surface receptors, Jak kinases (TYK2 and JAK1) are activated, leading to tyrosine phosphorylation of STAT1 and STAT2. The phosphorylated STATs dimerize, associate with IRF9/ISGF3G to form a complex termed ISGF3 transcription factor, that enters the nucleus. ISGF3 binds to the IFN stimulated response element (ISRE) to activate the transcription of interferon stimulated genes, which drive the cell in an antiviral state.
  • Sequence similarities
    Belongs to the IRF family.
    Contains 1 IRF tryptophan pentad repeat DNA-binding domain.
  • Cellular localization
    Cytoplasm. Nucleus. Translocated into the nucleus upon activation by IFN-alpha/beta.
  • Information by UniProt
  • Database links
  • Alternative names
    • IFN alpha responsive transcription factor subunit antibody
    • IFN-alpha-responsive transcription factor subunit antibody
    • Interferon regulatory factor 9 antibody
    • interferon stimulated transcription factor 3 antibody
    • Interferon-stimulated gene factor 3 gamma antibody
    • interferon-stimulated transcription factor 3, gamma 48kDa antibody
    • IRF 9 antibody
    • IRF-9 antibody
    • Irf9 antibody
    • IRF9_HUMAN antibody
    • ISGF 3 gamma antibody
    • ISGF-3 gamma antibody
    • ISGF3 antibody
    • ISGF3 p48 subunit antibody
    • ISGF3G antibody
    • OTTHUMP00000164692 antibody
    • OTTHUMP00000164693 antibody
    • p48 antibody
    • Transcriptional regulator ISGF3 subunit gamma antibody
    see all


  • Anti-Interferon regulatory factor 9 / IRF-9 antibody (ab51639) at 1 µg/ml + HepG2
    cell lysate at 15 µg

    HRP conjugated anti-Rabbit IgG at 1/50000 dilution

    Predicted band size: 44 kDa
    Observed band size: 41 kDa (why is the actual band size different from the predicted?)

  • ICC/IF image of ab51639 stained HeLa cells. The cells were 4% formaldehyde fixed (10 min) and then incubated in 1%BSA / 10% normal goat serum / 0.3M glycine in 0.1% PBS-Tween for 1h to permeabilise the cells and block non-specific protein-protein interactions. The cells were then incubated with the antibody (ab51639, 1µg/ml) overnight at +4°C. The secondary antibody (green) was ab96899, DyLight® 488 goat anti-rabbit IgG (H+L) used at a 1/250 dilution for 1h. Alexa Fluor® 594 WGA was used to label plasma membranes (red) at a 1/200 dilution for 1h. DAPI was used to stain the cell nuclei (blue) at a concentration of 1.43µM.

  • Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections) analysis of human liver tissue labelling Interferon regulatory factor 9 / IRF-9 with ab51639 at 4-8µg/ml. Arrows indicate positively labelled hepatocytes. Magnification: 400X.


This product has been referenced in:
  • Bidwell BN  et al. Silencing of Irf7 pathways in breast cancer cells promotes bone metastasis through immune escape. Nat Med : (2012). Human . Read more (PubMed: 22820642) »

See 1 Publication for this product

Customer reviews and Q&As

Abcam has not validated the combination of species/application used in this Abreview.
Western blot
Mouse Cell lysate - whole cell (RAW264.7)
Gel Running Conditions
Reduced Denaturing (12% acrylamide gel)
Loading amount
40 µg
Blocking step
Milk as blocking agent for 1 hour(s) and 0 minute(s) · Concentration: 5% · Temperature: 4°C

Bharat Bhatt

Verified customer

Submitted Mar 02 2018

Abcam has not validated the combination of species/application used in this Abreview.
Western blot
Mouse Cell lysate - whole cell (MEFs)
Gel Running Conditions
Reduced Denaturing (8%)
Loading amount
20 µg
Blocking step
Milk as blocking agent for 1 hour(s) and 15 minute(s) · Concentration: 5% · Temperature: 25°C

Abcam user community

Verified customer

Submitted Dec 26 2012

Expiration date: February 20, 2013
Value: $337

This code will give you $337 off your next order before the expiration date. To redeem this offer, please submit an Abreview for ab51639 with mouse samples, and inclu...

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Thank you very much for your interest our AbTrial program.

To our knowledge, ab51639 has not been tested with mouse samples. However by participating in our AbTrial program you can now use our products in an untested application or species w...

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Thank you for contacting us.

I can confirm that the laboratory obtained good results using heat induced antigen retrieval with Citrate buffer pH 6.

I hope this information is helpful to you. Please do not hesitate to contact us if...

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