Epitope Mapping Service

Epitope mapping is a method that is often employed to identify the antigen binding sites of an antibody. However, epitope mapping can also be used in other protein interactions with high affinity, including those with proteins, chemicals, and DNA. RayBiotech’s peptide array-based epitope mapping service uses high-quality peptides that are chemically synthesized, thereby negating many of the steps and time required with the traditional approach that involves recombinant cloning, expression, and purification of different regions of the target gene.

RayBiotech’s comprehensive epitope mapping service includes peptide design and synthesis, array printing, sample testing, and report generation. Just send us your samples, and we’ll send you the report!


Pre-Designed Epitope Mapping Arrays

Cytotoxic T-Lymphocyte Associated Protein 4 (CTLA4)
Lymphocyte Activating 3 (LAG3)
Programmed Cell Death 1 (PD-1)
Programmed Death Ligand 1 (PD-L1)
Interleukin 2 (IL-2)
Tumor necrosis factor alpha (TNF-alpha)

How It Works

RayBiotech’s peptide-based epitope mapping arrays are prepared by first printing overlapping, chemically-synthesized peptides (> 95% purity) spanning the length of the protein-of-interest onto a glass slide surface in an arrayed format, with each peptide spotted in triplicate. Multiple positive and negative controls are also printed onto the array to monitor each incubation step. Purified antibodies or bodily fluids containing antibodies are then diluted and incubated on the peptide arrays, during which the antibodies specifically bind to the peptides displaying their sequence-of-interest. After unbound antibodies are washed off the array, a biotin-conjugated secondary antibody (e.g., anti-human IgG, mouse IgG) and a fluorescence dye-conjugated streptavidin molecule are added to the array to enable the detection of bound antibodies bound. Fluorescent signal is then captured using a laser scanner. Since the peptide sequence of each spot is known, the antibody’s potential epitope(s) can be ascertained.


In addition to custom epitope mapping arrays, RayBiotech offers pre-designed peptide panels for popular drug targets. For more information, please contact our technical support team at [email protected].

Pre-Made Epitope Mapping Array


  • Identify high antigenicity epitopes for antibody production & vaccine development
  • Locate (auto)antigen epitopes of (auto)antibodies
  • Define the best antibody clone against the protein-of-interest
  • Perform epitope mutant analysis
  • Map B cell epitopes

Service Features

  • Small serum sample volume required (2 µl)
  • High density (simultaneously analyze hundreds of overlapping peptides)
  • High sensitivity
  • Large dynamic range
  • Suitable for high-throughput assays
  • High efficiency and accuracy
  • Affordable, quick and simple to use

Peptide array images showing antibody binding to its peptide epitope using a RayBiotech's peptide-based epitope mapping array. Biotin-BSA and mouse IgG were printed and used as positive controls. Arrays S1, S2, and S3 were incubated with the monoclonal antibody (mAb) at 200, 400, and 800-fold dilutions, respectively. CTL array was incubated without the mAb. The epitope sequence, represented by Peptide #8, is indicated with an arrow in array S1.

Fluorescence signal of the peptide array probed with the mAb. Background signal is represented by data from the CTRL array (see figure above). Of the 11 peptides, Peptide #8 had the strongest signal, which significantly increased with an increase in the mAb antibody concentration. The normalized data is shown on the left and the signal to noise (S:N) ratio is shown on the right.

Note: RayBiotech would like to thank Dr. Clemens Duerrschmid (Baylor College of Medicine, Houston, TX) for allowing us to present this data.


Frequently Asked Questions

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Antibodies (serum, plasma, ascites, recombinant antibodies, purified antibodies), chemicals, aptamer, or any other binders.

Human IgG and mouse IgG. Other isotypes (IgA, IgM, IgE, etc.) derived from most animals, upon request.

Fluorescence captured by laser scanner. View compatible laser scanners. RayBiotech also offers free scanning and data extraction services.

The results are semi-quantitative.

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