• Product name
    Anti-IRF3 antibody [EP2419Y]
    See all IRF3 primary antibodies
  • Description
    Rabbit monoclonal [EP2419Y] to IRF3
  • Host species
  • Tested applications
    Suitable for: WB, IP, IHC-P, Flow Cytmore details
    Unsuitable for: ICC
  • Species reactivity
    Reacts with: Human
  • Immunogen

    Synthetic peptide within Human IRF3 (C terminal). The exact sequence is proprietary.

  • Positive control
    • U937, HeLa, MCF7 and Jurkat cell lysates; human tonsil tissue.
  • General notes


    Mouse, Rat: We have preliminary internal testing data to indicate this antibody may not react with these species. Please contact us for more information. 

    Our RabMAb® technology is a patented hybridoma-based technology for making rabbit monoclonal antibodies. For details on our patents, please refer to RabMab® patents

    This product is a recombinant rabbit monoclonal antibody.



Our Abpromise guarantee covers the use of ab76409 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
WB 1/1000 - 1/2000. Predicted molecular weight: 47 kDa.
IP 1/20.
IHC-P 1/100 - 1/250. Perform heat mediated antigen retrieval via the pressure cooker method before commencing with IHC staining protocol.
Flow Cyt 1/10.

ab172730 - Rabbit monoclonal IgG, is suitable for use as an isotype control with this antibody.

  • Application notes
    Is unsuitable for ICC.
  • Target

    • Function
      Mediates interferon-stimulated response element (ISRE) promoter activation. Functions as a molecular switch for antiviral activity. DsRNA generated during the course of an viral infection leads to IRF3 phosphorylation on the C-terminal serine/threonine cluster. This induces a conformational change, leading to its dimerization, nuclear localization and association with CREB binding protein (CREBBP) to form dsRNA-activated factor 1 (DRAF1), a complex which activates the transcription of genes under the control of ISRE. The complex binds to the IE and PRDIII regions on the IFN-alpha and IFN-beta promoters respectively. IRF-3 does not have any transcription activation domains.
    • Tissue specificity
      Expressed constitutively in a variety of tissues.
    • Sequence similarities
      Belongs to the IRF family.
      Contains 1 IRF tryptophan pentad repeat DNA-binding domain.
    • Post-translational
      Constitutively phosphorylated on many serines residues. C-terminal serine/threonine cluster is phosphorylated in response of induction by IKBKE and TBK1. Ser-385 and Ser-386 may be specifically phosphorylated in response to induction. An alternate model propose that the five serine/threonine residues between 396 and 405 are phosphorylated in response to a viral infection. Phosphorylation, and subsequent activation of IRF3 is inhibited by vaccinia virus protein E3.
      Ubiquitinated; ubiquitination involves RBCK1 leading to proteasomal degradation. Polyubiquitinated; ubiquitination involves TRIM21 leading to proteasomal degradation.
      ISGylated by HERC5 resulting in sustained IRF3 activation and in the inhibition of IRF3 ubiquitination by disrupting PIN1 binding. The phosphorylation state of IRF3 does not alter ISGylation.
    • Cellular localization
      Cytoplasm. Nucleus. Shuttles between cytoplasmic and nuclear compartments, with export being the prevailing effect. When activated, IRF3 interaction with CREBBP prevents its export to the cytoplasm.
    • Information by UniProt
    • Database links
    • Alternative names
      • IIAE7 antibody
      • Interferon regulatory factor 3 antibody
      • IRF 3 antibody
      • IRF-3 antibody
      • IRF3 antibody
      • IRF3_HUMAN antibody
      • MGC94729 antibody
      see all


    • Lane 1: Wild-type HAP1 cell lysate (20 µg)
      Lane 2: IRF3 knockout HAP1 cell lysate (20 µg)
      Lane 3: HeLa cell lysate (20 µg)
      Lane 4: Jurkat cell lysate (20 µg)

      Lanes 1 - 4: Merged signal (red and green). Green - ab76409 observed at 50 kDa. Red - loading control, ab8245, observed at 37kDa.

      ab76409 was shown to react with IRF3 in wild-type HAP1 cells alond with additional cross-reactive bands. No band was observed when IRF3 knockout samples were used. Wild-type and IRF3 knockout samples were subjected to SDS-PAGE. ab76409 and ab8245 (loading control to GAPDH) were both diluted 1/1000 and 1/10,000 respectively and incubated overnight at 4°C. Blots were developed with Goat anti-Rabbit IgG H&L (IRDye® 800CW) preadsorbed (ab216773) and Goat anti-Mouse IgG H&L (IRDye® 680RD) preadsorbed (ab216776) secondary antibodies at 1/10,000 dilution for 1 hour at room temperature before imaging.

    • All lanes : Anti-IRF3 antibody [EP2419Y] (ab76409) at 1/2000 dilution

      Lane 1 : U937 cell lysate
      Lane 2 : Hela cell lysate
      Lane 3 : MCF7 cell lysate
      Lane 4 : Jurkat cell lysate

      Lysates/proteins at 10 µg per lane.

      All lanes : HRP labelled goat anti-rabbit at 1/2000 dilution

      Predicted band size: 47 kDa
      Observed band size: 47 kDa

    • Immunohistochemical analysis of IRF3 in paraffin embedded human tonsils using ab76409 at a 1/100 dilution.
    • Flow cytometric analysis of permeabilized U937 cells using anti- IRF-3 RabMAb (red) (ab76409) or a rabbit IgG (negative) (green)


    This product has been referenced in:
    • Qi N  et al. Multiple truncated isoforms of MAVS prevent its spontaneous aggregation in antiviral innate immune signalling. Nat Commun 8:15676 (2017). Read more (PubMed: 28607490) »
    • Huang LY  et al. Poly(I:C) Induces Human Lung Endothelial Barrier Dysfunction by Disrupting Tight Junction Expression of Claudin-5. PLoS One 11:e0160875 (2016). Human . Read more (PubMed: 27504984) »

    See all 8 Publications for this product

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