• Product name
  • Description
    Mouse monoclonal to IRF1
  • Tested applications
    Suitable for: WB, Flow Cytmore details
  • Species reactivity
    Reacts with: Human
  • Immunogen

    Recombinant fragment, corresponding to amino acids 216-326 of Human IRF1

  • General notes

    Abcam is committed to meeting high standards of ethical manufacturing and as such, we will be discontinuing this product, which has been generated by the ascites method, within the next year. We are sorry for any inconvenience this may cause. If you would like help finding an alternative product, please do not hesitate to contact our scientific support team.



Our Abpromise guarantee covers the use of ab55330 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 Use a concentration of 1 - 5 µg/ml. Predicted molecular weight: 37 kDa.
Flow Cyt Use 0.5µg for 106 cells.

ab170191 - Mouse monoclonal IgG2a, is suitable for use as an isotype control with this antibody.


  • Function
    Specifically binds to the upstream regulatory region of type I IFN and IFN-inducible MHC class I genes (the interferon consensus sequence (ICS)) and activates those genes. Acts as a tumor suppressor.
  • Involvement in disease
    Defects in IRF1 are a cause of gastric cancer (GASC) [MIM:613659]; also called gastric cancer intestinal or stomach cancer. Gastric cancer is a malignant disease which starts in the stomach, can spread to the esophagus or the small intestine, and can extend through the stomach wall to nearby lymph nodes and organs. It also can metastasize to other parts of the body. The term gastric cancer or gastric carcinoma refers to adenocarcinoma of the stomach that accounts for most of all gastric malignant tumors. Two main histologic types are recognized, diffuse type and intestinal type carcinomas. Diffuse tumors are poorly differentiated infiltrating lesions, resulting in thickening of the stomach. In contrast, intestinal tumors are usually exophytic, often ulcerating, and associated with intestinal metaplasia of the stomach, most often observed in sporadic disease.
  • Sequence similarities
    Belongs to the IRF family.
    Contains 1 IRF tryptophan pentad repeat DNA-binding domain.
  • Post-translational
    Sumoylation represses the transcriptional activity and displays enhanced resistance to protein degradation. Inactivates the tumor suppressor activity. Elevated levels in tumor cells. Major site is Lys-275. Sumoylation is enhanced by PIAS3 (By similarity). Desumoylated by SENP1 in tumor cells and appears to compete with ubiquitination on C-terminal sites.
    Ubiquitinated. Appears to compete with sumoylation on C-terminal sites.
  • Cellular localization
  • Information by UniProt
  • Database links
  • Alternative names
    • Interferon regulatory factor 1 antibody
    • Interferon regulatory factor 1 isoform +I9 antibody
    • Interferon regulatory factor 1 isoform d78 antibody
    • Interferon regulatory factor 1 isoform delta4 antibody
    • Interferon regulatory factor 1 isoform delta7 antibody
    • IRF 1 antibody
    • IRF-1 antibody
    • IRF1 antibody
    • IRF1_HUMAN antibody
    • MAR antibody
    • MAR1 antibody
    see all


  • Predicted band size : 37 kDa
    IRF1 antibody (ab55330) at 1ug/lane + COLO cell lysate at 25ug/lane.
  • Overlay histogram showing Jurkat cells stained with ab55330 (red line). The cells were fixed with 80% methanol (5 min) and then permeabilized with 0.1% PBS-Tween for 20 min. The cells were then incubated in 1x PBS / 10% normal goat serum / 0.3M glycine to block non-specific protein-protein interactions. The cells were then incubated with the antibody (ab55330, 0.5µg/1x106 cells) for 30 min at 22ºC. The secondary antibody used was DyLight® 488 goat anti-mouse IgG (H+L) (ab96879) at 1/500 dilution for 30 min at 22ºC. Isotype control antibody (black line) was mouse IgG2a [ICIGG2A] (ab91361, 1µg/1x106 cells ) used under the same conditions. Acquisition of >5,000 events was performed.


This product has been referenced in:
  • El Jamal SM  et al. Interferon gamma-induced apoptosis of head and neck squamous cell carcinoma is connected to indoleamine-2,3-dioxygenase via mitochondrial and ER stress-associated pathways. Cell Div 11:11 (2016). WB ; Human . Read more (PubMed: 27486476) »
  • Osborn SL  et al. Induction of human embryonic and induced pluripotent stem cells into urothelium. Stem Cells Transl Med 3:610-9 (2014). Human . Read more (PubMed: 24657961) »

See all 3 Publications for this product

Customer reviews and Q&As

Thank you for the additional details of your sample preparation.

The western blot we show on our datasheet places the size of the protein at about 37 kDa. This corresponds to the predicted molecular weight of the sequence for human IRF1 give...

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Thank you for bringing this to our attention. We have not had other reports of a band between 55 and 70 kDa. Your protocol looks correct, and my only concerns are how the sample was prepared before loading in to the gel, and how the antibody was stored...

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