Conformational B Cell Epitope Mapping Services

Background Service Highlight Service Highlight Published Data FAQ Resources

Epitope mapping aims at identifying the binding sites of antibodies on their target antigens. It has become increasingly important in many immunological applications, including the discovery and development of new vaccines and antibody drugs. With skills and knowledge on epitope mapping, Creative Biolabs provides B cell epitope mapping services specializing in conformational and linear B-Cell epitopes.

Introduction of B Cell Epitope

B cells are considered to be a core component of the adaptive immune system because they provide long-term protection against infectious pathogens. They perform these functions by producing antibodies that recognize their molecular target (called antigen) by binding to a part of it (called epitope) in a highly selective manner. Thus, epitopes are binding areas on antigens. B cell epitopes are classified into two categories: linear (continuous or sequential) and conformational (nonlinear or discontinuous) epitopes. The linear B cell epitopes are made up of contiguous stretch of amino acids in antigen, whereas conformational B cell epitopes constitute the spatially folded amino acids, which lie far away in the protein sequence. 10% of the epitopes belong to the linear table, and 90% of the epitopes belong to the conformational epitope. Although the majority of B cell epitopes are conformational, most of them are composed of 1–5 linear stretches.

Fig.1 B cell epitope.

Conformational B-Cell Epitopes Mapping Methods

Conformational B-cell epitopes have been studied extensively due to their immunological applications, such as peptide-based vaccine development, antibody production, and disease diagnosis and therapy. Epitope mapping of an antibody will greatly facilitate antibody drug discovery and design. Experimental epitope mapping can be generally divided into structural and functional studies.

Structural approaches
The most commonly used method for structural epitope mapping is X-ray crystallography, which is used to map linear and conformational epitopes and provides information on the binding strength of antigen-antibody (Ag-Ab) complexes. However, X-ray crystallography is limited by the quality of cocrystals and electron density of the antibody. To this end, nuclear magnetic resonance (NMR) and electron microscopy (EM) has been developed to compensate for the deficiencies of conventional X-ray crystallography. NMR provides data on the structure, kinetics and binding energy of the Ag-Ab complex and is carried out in a solution that does not require crystals. For small proteins and peptides (<25 kDa), NMR can be used for mapping, and for very large assemblies (such as whole viral particles), EM can be used to identify approximate contact areas.
Functional approaches
Methods for functional epitope mapping can be divided into four groups: competition mapping, protein fragmentation, antigen modification, and synthetic peptides or peptide libraries method. Most functional methods are based on the ability to detect binding of the antibody to antigen fragments, synthetic peptides, or recombinant antigens (including mutant variants, antigens arrayed by in situ cell-free translation, and/or expressed using selectable systems such as phage display). In the binding assay, the peptide is immobilized on a solid support and the binding of the antibody is detected by Western blot, dot blot and/or ELISA. This method does not require expensive equipment and is capable of quantifying immune responses to specific epitopes. The peptides can be synthesized on pins, on a cellulose membrane support, or on peptide microarrays. These methods simplify the processing of a large number of peptides and do not require the identification of positive peptides by sequencing or mass spectrometry. Binding assays have been successfully used to identify epitopes in several viruses, bacteria, fungi, parasites, and human diseases.

Our Service for Conformational B-Cell Epitopes Mapping

X-ray crystallography
Competition mapping
Protein fragmentation
Antigen modification
Synthetic peptides or peptide libraries construction
Other customized services

Workflow & Deliverables

B cell epitope.

Features

Applicable to all types of epitopes, including linear, conformational epitopes and complex epitopes involving multimeric protein complexes
Applicable to all kinds of samples: Mabs, antibody-like scaffolds and polyclonal sera
Applicable to all kinds of target proteins soluble as well as membrane integrated proteins, viral capsids
Accurate, fast and cost-effective: multiple screenings on one array

Creative Biolabs' dedicated immunologists and excellent teams can add real value to your research projects. Contact us to discuss your project and we will design an assay tailored to achieve your objectives.

Other optional CreMap™ B cell epitope mapping services:

Published Data

Identification of Conformational B Cell Epitopes Using Phage Display Technique

Fig. 2 Structural analysis of HlyE conformational epitope. (Chai Fung Chin, 2017)

The study focused on identifying conformational B-cell epitopes of the HlyE toxin from Salmonella enterica serovar Typhi (S. Typhi) using the phage display technique. This research elucidates potential immunogenic regions on HlyE that could be targeted for vaccine development against typhoid fever. The application of conformational B cell epitope mapping in this study involved using a 20-mer random peptide library to biopan enriched polyclonal antibodies from typhoid patient sera. The peptides that bound to the antibodies were sequenced, and bioinformatic tools helped predict and validate the conformational epitopes on HlyE. These epitopes were confirmed through binding assays, providing a foundation for developing targeted interventions against Salmonella Typhi.

Reference

Chin, Chai Fung, et al. "Delineation of B-cell Epitopes of Salmonella enterica serovar Typhi Hemolysin E: Potential antibody therapeutic target." Scientific Reports 7.1 (2017): 2176.

FAQ

What is conformational B cell epitope mapping?
Conformational B cell epitope mapping is a technique used to identify the specific three-dimensional regions of an antigen that are recognized by B cell antibodies. These epitopes are formed by amino acid residues that are brought together in the folded structure of the protein, rather than by a continuous linear sequence. This mapping is essential for understanding complex immune responses and designing effective vaccines and therapeutic antibodies.
How is conformational B cell epitope mapping performed?
Conformational B cell epitope mapping typically involves techniques such as X-ray crystallography, cryo-electron microscopy, or nuclear magnetic resonance (NMR) spectroscopy. These methods allow researchers to determine the three-dimensional structure of antigen-antibody complexes. Additionally, techniques like hydrogen-deuterium exchange mass spectrometry (HDX-MS) and mutagenesis can identify regions of the antigen that interact with antibodies, providing insights into conformational epitopes.
What are the advantages of conformational B cell epitope mapping?
Conformational B cell epitope mapping has the ability to identify epitopes that depend on the protein's three-dimensional structure. This method provides a more comprehensive understanding of antibody-antigen interactions, which is crucial for designing vaccines and therapeutics that target complex epitopes. It also helps in identifying epitopes that are not accessible in linear mapping, offering a more complete picture of immune recognition.
What applications can benefit from conformational B cell epitope mapping?
Conformational B cell epitope mapping is beneficial for vaccine development, therapeutic antibody design, and understanding autoimmune diseases. It aids in identifying immunogenic regions of pathogens that are crucial for eliciting an immune response. This technique is also valuable in studying antibody specificity and cross-reactivity, which is important for developing targeted therapies and diagnostics.
How does conformational B cell epitope mapping contribute to vaccine development?
Conformational B cell epitope mapping contributes to vaccine development by identifying the three-dimensional regions of antigens that are most effective in eliciting an immune response. By targeting these conformational epitopes, researchers can design vaccines that mimic the natural structure of the pathogen, leading to more robust and protective immune responses. This approach helps in creating vaccines with higher efficacy and safety profiles.
What are the limitations of conformational B cell epitope mapping compared to linear epitope mapping?
Conformational B cell epitope mapping can be more complex and time-consuming than linear epitope mapping, as it requires detailed structural information about the antigen-antibody complexes. Techniques such as X-ray crystallography and cryo-EM can be expensive and require specialized equipment and expertise. Additionally, conformational mapping may not always identify linear epitopes, necessitating a combination of both methods for comprehensive epitope identification.
How does conformational B cell epitope mapping improve the understanding of immune responses?
Conformational B cell epitope mapping can identify the three-dimensional regions within antigens that are targeted by antibodies. This detailed information helps elucidate the mechanisms of immune recognition, antibody specificity, and cross-reactivity. It provides insights into the structural basis of immune responses, aiding in the design of effective vaccines and immunotherapies that mimic natural antigenic structures.