• Product name
    Anti-Cytokeratin 18 antibody [E431-1]
    See all Cytokeratin 18 primary antibodies
  • Description
    Rabbit monoclonal [E431-1] to Cytokeratin 18
  • Host species
  • Specificity
    Human Cytokeratin 18 (K18) was used as immunogen after isolation from cells pre-treated with okadaic acid or pervanadate to promote Tyr hyperphosphorylation.
  • Tested applications
    Suitable for: WB, IHC-P, ICC/IF, Flow Cyt, IHC-Frmore details
    Unsuitable for: IP
  • Species reactivity
    Reacts with: Human
  • Immunogen

    Full length native protein (purified) corresponding to Human Cytokeratin 18.

  • Positive control
    • WB: A431 cell lysate. IHC: Human gastric adenocarcinoma, kidney, colon, breast carcinoma, brain and glioma tissue. ICC/ IF: HT-29 cell lysate. Flow Cyt: MCF7 cells.
  • General notes

    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 ab32118 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 1/10000. Detects a band of approximately 48 kDa (predicted molecular weight: 48 kDa).
IHC-P Use at an assay dependent concentration.
ICC/IF 1/100 - 1/500.


Flow Cyt 1/20.

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

IHC-Fr Use at an assay dependent dilution.
  • Application notes
    Is unsuitable for IP.
  • Target

    • Function
      Involved in the uptake of thrombin-antithrombin complexes by hepatic cells (By similarity). When phosphorylated, plays a role in filament reorganization. Involved in the delivery of mutated CFTR to the plasma membrane. Together with KRT8, is involved in interleukin-6 (IL-6)-mediated barrier protection.
    • Tissue specificity
      Expressed in colon, placenta, liver and very weakly in exocervix. Increased expression observed in lymph nodes of breast carcinoma.
    • Involvement in disease
      Defects in KRT18 are a cause of cirrhosis (CIRRH) [MIM:215600].
    • Sequence similarities
      Belongs to the intermediate filament family.
    • Post-translational
      Phosphorylation at Ser-34 increases during mitosis. Hyperphosphorylated at Ser-53 in diseased cirrhosis liver. Phosphorylation increases by IL-6.
      Proteolytically cleaved by caspases during epithelial cell apoptosis. Cleavage occurs at Asp-238 by either caspase-3, caspase-6 or caspase-7.
      O-glycosylated at multiple sites; glycans consist of single N-acetylglucosamine residues.
    • Cellular localization
      Cytoplasm > perinuclear region.
    • Information by UniProt
    • Database links
    • Alternative names
      • Cell proliferation inducing gene 46 protein antibody
      • Cell proliferation inducing protein 46 antibody
      • Cell proliferation-inducing gene 46 protein antibody
      • CK 18 antibody
      • CK-18 antibody
      • CK18 antibody
      • CYK 18 antibody
      • CYK18 antibody
      • Cytokeratin 18 antibody
      • Cytokeratin endo B antibody
      • Cytokeratin-18 antibody
      • K 18 antibody
      • K18 antibody
      • K1C18_HUMAN antibody
      • KA18 antibody
      • Keratin 18 antibody
      • Keratin 18, type I antibody
      • Keratin D antibody
      • keratin, type I cytoskeletal 18 antibody
      • Keratin-18 antibody
      • Krt18 antibody
      see all


    • Indirect immunofluorescence staining with antibodies against DNA, cytokeratin-7 and cytokeratin-18 (upper panel) or against DNA, vimentin and cytokeratin-18 (lower panel). Representatives are presented. Scale bar: 20 µm.

      Control or treated cells were fixed for 15 min with 4% PFA containing 0.1% Triton X-100 at room temperature. The following primary antibodies were used for staining: monoclonal mouse antibodies against vimentin and cytokeratin-7 (both 1:100, DAKO) and monoclonal rabbit antibody against cytokeratin-18 (1:50, Abcam). DNA was stained using DAPI (4’,6-diamidino-2-phenylindole-dihydrochlorid) (Roche). Slides were examined using an Axio Imager 7.1 microscope (Zeiss) and images were taken using an Axio Cam MRm camera (Zeiss). The immunofluorescence stained slides were also examined by a confocal laser scanning microscope (CLSM) (Leica CTR 6500, Heidelberg). Images were processed using Photoshop.

    • Immunocytochemistry/Immunofluorescence analysis of HT-29 cells labelling Cytokeratin 18 with purified ab32118 at 1/500. Cells were fixed with 100% Methanol. An Alexa Fluor® 488-conjugated goat anti-rabbit IgG (ab150077) at 1/1000 dilution was used as the secondary antibody. The cells were co-stained with ab7291, a mouse anti-tubulin antibody (1/1000) using ab150120, an Alexa Fluor® 594-conjugated goat anti-mouse IgG (1/1000) as the secondary antibody. Nuclei were counterstained with DAPI (blue).

      For negative control 1, rabbit primary antibody was used followed by anti-mouse secondary antibody (ab150120).
      For negative control 2, mouse primary antibody (ab7291) and anti-rabbit secondary antibody (ab150077) were used.

    • ab32118 showing positive staining in Normal colon tissue.

    • Anti-Cytokeratin 18 antibody [E431-1] (ab32118) at 1/10000 dilution + A431 cell lysate

      Predicted band size: 48 kDa
      Observed band size: 48 kDa

    • Overlay histogram showing MCF7 cells stained with ab32118 (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 followed by the antibody (ab32118, 1/100 dilution) for 30 min at 22ºC. The secondary antibody used was DyLight® 488 goat anti-rabbit IgG (H+L) (ab96899) at 1/500 dilution for 30 min at 22ºC. Isotype control antibody (black line) was rabbit IgG (monoclonal) (1µg/1x106 cells) used under the same conditions. Acquisition of >5,000 events was performed. This antibody gave a positive signal in MCF7 cells fixed with 4% paraformaldehyde (10 min)/permeabilized with 0.1% PBS-Tween for 20 min used under the same conditions.

    • ab32118 showing positive staining in Gastric adenocarcinoma tissue.

    • Fluorescent immunohistochemical analysis of paraffin-embedded human normal kidney tissue using ab32118. Green-CK18 red-PI

    • ab32118 showing positive staining in Normal kidney tissue.

    • ab32118 showing positive staining in Breast carcinoma tissue.

    • ab32118 showing negative staining in Glioma tissue.

    • ab32118 showing negative staining in Normal brain tissue.


    This product has been referenced in:
    • Duchemin-Pelletier E  et al. Stem Cell-Like Properties of CK2ß-down Regulated Mammary Cells. Cancers (Basel) 9:N/A (2017). Read more (PubMed: 28858215) »
    • Huang W  et al. The matricellular protein CCN6 (WISP3) decreases Notch1 and suppresses breast cancer initiating cells. Oncotarget 7:25180-93 (2016). Read more (PubMed: 26933820) »
    See all 23 Publications for this product

    Customer reviews and Q&As

    1-10 of 13 Abreviews or Q&A

    Immunocytochemistry/ Immunofluorescence
    Human Cell (HeLa)
    Yes - 0.5% TritonX100 in PBS

    Dr. Kirk Mcmanus

    Verified customer

    Submitted Jun 03 2015


    86% homology - could detect the target signal at 1:1000 in mouse kidney and spleen using 5-fold more sensitive ECL substrate than the one we usually use.

    89% homology - blank WB in mouse brain, heart, lung, muscle, spleen

    Read More


    Although mouse samples were not recommended based on the western blot results below with these antibodies, there is still the possibility that the negative results in mouse might be due to the limited sample types, especially for the antibodies with high homology (more than 80%) with mouse proteins.
    CK 18
    ab32118: waiting homology and mouse testing
    CK 8
    ab32357: waiting homology, blank WB in mouse brain, heart, lung, muscle, spleen
    CK 7
    ab52870: no homology, no mouse testing performed due to no homology
    CK 19
    ab76539: 80% homology, blank WB in mouse brain, heart, kidney, spleen
    CK 18
    ab133272: 93% homology, blank WB in mouse brain, heart, kidney, spleen, NIH/3T3, Raw264.7
    CK 18
    ab133302: 86% homology, blank WB in mouse brain, heart, kidney, spleen, NIH/3T3, Raw 264.7
    ab133260: 100% homology, blank WB in mouse brain, heart, kidney, spleen. Non-specific bands in NIH/3T3.
    I could not find any antibodies in our catalog that have low homology with mouse. Your best option is to look for an antibody with an immunogen between human Epcam aa 36-53, the least homologous region of the protein with mouse Epcam. We do provide custom antibody creation in which we can create a rabbit monoclonal antibody with a synthetic peptide in a region of your choosing, please let me know if this is something you are interested in, and I'd be happy to put you in contact with our custom antibody services group.

    Read More
    Abcam guarantees this product to work in the species/application used in this Abreview.
    Immunohistochemistry (Frozen sections)
    Blocking step
    Serum as blocking agent for 1 hour(s) and 0 minute(s) · Concentration: 5% · Temperature: RT°C
    Human Tissue sections (A549)
    Yes - 0.5 Triton X-100

    Mrs. Aleksandra Kotlyarova

    Verified customer

    Submitted Sep 26 2013

    Abcam has not validated the combination of species/application used in this Abreview.
    Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections)
    Mouse Tissue sections (Pancreas)
    Antigen retrieval step
    Heat mediated - Buffer/Enzyme Used: Citrae pH 6
    Blocking step
    BSA / FBS as blocking agent for 30 minute(s) · Concentration: 1% · Temperature: RT°C

    Mr. Raul Peña

    Verified customer

    Submitted Dec 03 2012


    Thank you very much for your answer.
    I have contacted the laboratory to gather some more information in regards to the species testing of these antibodies. I am sorry it has taken so long time. Have you already proceeded meanwhile?
    In regards to the cytokeratin 18 antibody - as far as I know, the cytokeratins are all cytoplasmic. The ab32118 has been tested in flow cytometry on permeabilized cells (with methanol).
    In regards to the CD95 antibody ab133619, we do not think it crossreacts with mouse and rat as the immunogen shares only 45% identity with mouse and rat CD95. However there was a signal in mouse heart for which we could not determine whether it was specific or not. I am very sorry for not being able to provide you with a better answer still. What I however would like to offer is a testing discount: you would buy this antibody and test it. You would then provide the feedback via an Abreview. Once we have the feedback, you would receive an antibody of your choice from our catalog for free.
    If such a testing would interest you, please do let me know and I will describe you the offer in more details.
    If however you prefer looking at other antibodies, please let me know as well. I would be pleased to investigate also other antibodies of the list for you (and I would expect it being faster this time .. ).
    Please let me know if you have any question. I look forward to hear back from you.

    Read More


    Thank you for contacting us.
    I am sorry to hear this customer has been experiencing problems with 2 of our antibodies. Would it be possible to obtain more protocol information too so that we can investigate this in more detail?
    I look forward to your reply.

    Read More


    Thank you for your reply regarding ab32118.

    I am sorry that this product did not perform as stated on the datasheet and for the inconvenience this has caused. As requested, I have issued a free of charge replacement of ab668.

    To check the status of the order please contact our Customer Service team and reference this number.

    Please note that this free of charge replacement vial is also covered by our Abpromise guarantee. Should you still be experiencing difficulties, or if you have any further questions, please do not hesitate to let us know.

    I wish you the best of luck with your research.

    Read More


    Thank you for calling Abcam yesterday. I am sorry about the problems with ab32118. I have processed your request to receive ab668 as a free of charge replacement. Your new order number is ******. Please let me know if there is anything else I can help you with.

    Read More


    Thank you for contacting Abcam. The concentration of ab32118 is approximately 0.130mg/ml and the concentration for ab32118 is 0.185 mg/ml. If there is anything else I can do, please do hesitate to ask.

    Read More

    1-10 of 13 Abreviews or Q&A


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