• Product name
  • Description
    Rabbit polyclonal to IRF3
  • Host species
  • Specificity
    ab25950 recognises IRF3.
  • Tested applications
    Suitable for: IHC-P, ICC/IF, ELISA, WBmore details
  • Species reactivity
    Reacts with: Mouse, Human
  • Immunogen

    A synthetic peptide corresponding to 14 amino acids near the carboxyterminus of IRF3 (Human)

  • Positive control
    • Ramos whole cell lysate Mouse kidney This antibody gave a positive result when used in the following formaldehyde fixed cell lines: MCF-7.



Our Abpromise guarantee covers the use of ab25950 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
IHC-P Use a concentration of 2 µg/ml. Perform heat mediated antigen retrieval with citrate buffer pH 6 before commencing with IHC staining protocol.
ICC/IF Use a concentration of 1 µg/ml.
ELISA Use at an assay dependent concentration.
WB Use a concentration of 1 - 2 µg/ml. Detects a band of approximately 44 kDa (predicted molecular weight: 47 kDa).Can be blocked with Human IRF3 peptide (ab39792).


  • 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 : Anti-IRF3 antibody (ab25950) at 1 µg/ml
    Lane 2 : Anti-IRF3 antibody (ab25950) at 2 µg/ml
    Lane 3 : Anti-IRF3 antibody (ab25950) at 4 µg/ml

    All lanes : Ramos whole cell lysate.

    Predicted band size: 47 kDa
    Observed band size: ~44 kDa
    why is the actual band size different from the predicted?

  • ab25950 stained MCF-7 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 ab25950 at 1µg/ml overnight at +4°C. The secondary antibody (green) was DyLight® 488 goat anti- rabbit (ab96899) IgG (H+L) used at a 1/1000 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.

  • Anti-IRF3 antibody (ab25950) at 1/1000 dilution + HT-29 at 30 µg

    HRP conjugated Anti-rabbit IgG, Goat polyclonal at 1/1000 dilution

    Developed using the ECL technique.

    Predicted band size: 47 kDa

    Samples were incubated with primary antibody for 18 hours at 4ºC and blocked with 5% BSA for 1 hour at room temperature. 

    See Abreview

  • Immunofluorescence of IRF3 in Mouse Kidney cells using ab25950 at 20 ug/ml.

  • ab25950 at 2µg/ml staining IRF3 in mouse kidney by IHC.


This product has been referenced in:
  • Kim JH  et al. FAS-associated factor-1 positively regulates type I interferon response to RNA virus infection by targeting NLRX1. PLoS Pathog 13:e1006398 (2017). Read more (PubMed: 28542569) »
  • Kim JH  et al. Rubicon Modulates Antiviral Type I Interferon (IFN) Signaling by Targeting IFN Regulatory Factor 3 Dimerization. J Virol 91:N/A (2017). Read more (PubMed: 28468885) »
See all 16 Publications for this product

Customer reviews and Q&As

1-4 of 4 Abreviews or Q&A

Western blot
Human Cell lysate - other (HT-29)
Gel Running Conditions
Reduced Denaturing (10)
Loading amount
30 µg
Blocking step
BSA as blocking agent for 1 hour(s) and 0 minute(s) · Concentration: 5% · Temperature: RT°C

Abcam user community

Verified customer

Submitted Jan 18 2017

Western blot
Mouse Cell lysate - whole cell (mouse hepatocytes)
Gel Running Conditions
Reduced Denaturing
Loading amount
20 µg
20 ug/ml poly(I:C) for 24 hours
mouse hepatocytes
Blocking step
Milk as blocking agent for 1 hour(s) and 0 minute(s) · Concentration: 5% · Temperature: 23°C

Abcam user community

Verified customer

Submitted Sep 08 2015

Detection step
Real-time PCR
Mouse Cell lysate - nuclear (Fibroblast)
Negative control
Bead-only as negative control for antibody and primer set amplifying TBP promoter as qPCR negative control.
Cross-linking (X-ChIP)
Duration of cross-linking step: 10 minute(s) and 0 second(s)
Specification of the cross-linking agent: 1% Paraformaldehyde (EMS)
Positive control
Abcam ab7970 (p65 antibody) as positive control for antibody and primer set amplifying ISG15 promoter as the positive control for the qPCR.

Nima Mohaghegh

Verified customer

Submitted Feb 27 2014


We have only tested the antibody in a reduced, denatured Western blot. We are not sure whether it will bind to a dimer in a native Western blot. It is possible, but it's also possible that the epitope of the antibody (located in the C-terminus) will be obscured in the native or dimerized form, and in that case the antibody would not bind to the protein. We can not be sure of this until it is tested, however.

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