• Product name
    Anti-E. coli O + E. coli K antibody (HRP)
    See all E. coli O + E. coli K primary antibodies
  • Description
    Goat polyclonal to E. coli O + E. coli K (HRP)
  • Host species
  • Conjugation
  • Tested applications
    Suitable for: ELISA, ICC/IFmore details
  • Species reactivity
    Reacts with: Escherichia coli
  • Immunogen

    Mixture of E. coli serotypes.

  • General notes

    The antibody is covalently coupled to a highly purified preparation of horseradish peroxidase (RZ>3). Care is taken to ensure adequate conjugation while preserving maximum enzyme activity. Free enzyme is absent.



Our Abpromise guarantee covers the use of ab21110 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
ELISA Use at an assay dependent dilution.
ICC/IF Use at an assay dependent dilution.


  • Relevance
    Escherichia coli (E. coli) are Gram negative enteric bacteria that live in the human gut. Its presence in nature is an indication of human feacal pollution. E. coli also causes human disease such as urinary tract infections and neonatal meningitis. Infection with particular enterotoxigenic strains can lead to life threatening intestinal diseases. E. coli are distinguished immunologically by serotyping based on three types of antigen: the somatic or O antigen which corresponds to terminal sugars on the cell surface lipopolysaccharide, the capsular or K antigens and the flagellar or H antigens.
  • Alternative names
    • Capsular antigen antibody
    • Escherichia coli antibody
    • Escherichia coli K antibody
    • Escherichia coli O antibody
    • K antigen antibody
    • O antigen antibody
    see all


ab21110 has not yet been referenced specifically in any publications.

Customer reviews and Q&As

1-6 of 6 Abreviews or Q&A


Thank you for your email.

Could you let me know which antibody you would like to try? We have following abs available;




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Thank you for your email. I have taken over this case from XXXXX so I will be dealing with this case now on.

The protocol recommended by XXXXXXX is only valid for ab21110. The protocol for ab20771 is available online, please follow that to get the results.

From the results you have kindly sent I believe that perhaps the antibody have gone off during storage. The Abcam product guarantee applies to product when the complaints are raised within 6 month time which unfortunately was not the case for this product however we acknowledge the time you have spent in laboratory so we are happy making an exception this time and would like to offer you a replacement vial of ab21110.

Could you confirm if you are interested in receiving the same antibody or a different one?

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Thank you for your patience.

My colleague is out of office today but I wish to pass some useful information to you.

Whole bacteria do not absorb well when coated wet in ELISA wells. You may need to add different dilutions of the bacterial suspension and then let them dry down in the wells. This can be accomplished by letting the plate sit out overnight or by placing the plate in an incubator that has a fan function to circulate the air (also at room temp). When dry, the wells should then be washed well with a detergent buffer to remove any material that is not firmly fixed by drying.

We hope this will be useful for you.

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Dear Sir/ Madam,
Below, you may find the abcam questionaire for the antibodyab 21110.
1) Abcam product code ab ab21110
2) Abcam order reference number or product batch number: 988211

3) Description of the problem: No signal; The antibody does not detect adsorbed E.coli

4) Type of ELISA: direct

5) Sample details: E.coli in BHI medium

6) Target antigen (if found in heterogeneous sample)

7) Positive control: N/A
8) Negative control: BHI medium

9) Blocking agent (eg BSA…): BSA
Concentration: 3%
Blocking time: 2h
Blocking temperature: RT

10) Capture or Primary antibody information: N/A
Used to coat wells? Yes/no
Reacts against
Concentration or dilution
Diluent buffer
Incubation time
Incubation temperature

11)Detection antibody: ab21110
Species: Goat
Reacts against: many O and K antigenic serotypes of Escherichia coli.
Concentration or dilution: 1/1000 and 1/2000
Diluent buffer : PBST with 3% BSA
Incubation time: 1h
Incubation temperature: RT
Conjugation: HRP conjugated

12) Enzyme labelled secondary antibody: N/A
Reacts against
Concentration or dilution
Diluent buffer
Incubation time
Incubation temperature:

13) Washing after primary and secondary antibodies:
Buffer: PBST with BSA 3%
Number of washes: 2
Length of washes: 5 min

14) Substrate: TMB
Incubation time: 30 min

15) How many times have you run this ELISA? 4 times in triplicates
Do you obtain the same results every time? yes
What steps have you altered to try and optimize the use of this antibody? Increase the antibody concentration and compared with different concentrations of E.coli.

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Thank you for your email. I am sorry to hear that you have been experiencing problems with this antibody.

I have read the details you have kindly provided and have following further questions for better understanding of the problem;

- how exactly the antibody was used? Did you coat E.Coli sample to wells and then added antibody?
- Have you done any troubleshooting of protocol?
- Could you share ELISA results with us?
- The ab was purchased in Dec 2011; how it was stored until first use?
- How the E.Coli samples were prepared?
- Could you provide step by step followed protocol?

Abpromise guarantee applies to products if the problem is reported within 6 month from purchase. Could you explain why there was a delay in reporting for this complaint?

Thank you very much for your cooperation. I will look forward to hearing from you soon.

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I'm glad you found the information of help.

If you do test any of these antibodies we would be very interested to hear of the results, regardless of if they are positive or not. We like to encourage all of our customers to submit an Abreview via the online product datasheet with any data they collect with our antibodies. As a reward for doing this, each Abreview earns Abpoints that can be used for discounts on future purchases or rewards such as Amazon.com gift certificates.

To find out more about our Abreview system, please see the following link:


If you let me know which antibody in particular you are interested in using I may be able to provide you with a testing discount code. More information on this scheme can be found form the following link:


I hope this information has been of help. If you have any further questions, please do not hesitate to ask.

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Thank you for contacting us and your interest in our products.

I can now share some more information relating to the antibodies we have directed towards E. coli (O and K). We have two different antibodies directed against this bacterium, with different conjugation available:

ab31499, unlabelled(ab33604, FITC; ab33837, HRP; ab33839, Biotin conjugated of same antibody preparation as ab31499)

The immunogen for these antibodies is a mixture of the following E. coli strains: O157:H7, O20, O125, O55, O111 & K12. The mixture of these strains was of intact plus lysed bacteria which had not been denatured in any way. All E. coli have many surface and internal antigens in common and this antibody recognizes this large mixture and therefore reacts with most, if not all, E. coli. Theseantibodies have been tested against the strains listed above but have not been cross-absorbed and may react with related Enterobacteriaceae. These potential cross-reacting strains have not been identified.

ab20765, ab20856 and ab21110 are Biotin, FITC and HRP conjugates of the same antibody.

These antibodies have been raised against a mixture of E. coli serotypes.These antibodies have been tested for reactivity against the immunogen strains of E.coli but again they have not been absorbed and will most likely cross react withother related Enterobacteriaceae.

I am sorry that in this case I was not able to be of more help. If you have any further questions, please do not hesitate to contact us again.

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