What is an Epitope?


Antigen-Binding-SiteSimply put, an epitope is the antibody binding site on an antigen. However, to gain a stronger grasp of how all the pieces fit together it is helpful to start by reviewing the structure and function of an antibody. This is particularly useful when it comes to gaining a better understanding of how custom antibodies are developed.

When a foreign molecule is detected for the first time by the immune system of an organism the molecule, which is normally a protein, is captured by an army of highly specialized cells. One example is dendritic cells, which are antigen presenting cells responsible for helping to break down the foreign molecule into smaller parts and presenting them to B cell lymphocytes in the form of antigens.

Following Antigen Presentation, a cellular mechanism called Somatic Hypermutation initiates the coding process by the B cell lymphocyte of a new antibody. The Antigen Binding Site of the variable region of the antibody will be unique in order to specifically bind to an epitope derived from the antigen.

What is an Epitope Structure

An epitope is typically a protein segment that is five to six amino acids long. Thus, a full-length protein will have a variety of epitopes to where specific antibodies will bind. Amino acid sequences that are linear in shape are called Continuous epitopes while Discontinuous epitopes refer to amino acid sequences which have a folded conformation. Distinguishing between the two is an important consideration for custom antibody production.

It is important to note that a unique antibody is produced by a B cell lymphocyte which recognizes and binds to a single unique epitope. Overtime, antibodies are released by the B cells and travel throughout the bloodstream to aid the immune system in eradicating the foreign molecule that they have been programmed to recognize.

Antibodies Functions

Antibodies function both in direct and indirect capacities. For example, viruses are typically disabled by direct binding while pathogens that are bacterial in nature work more indirectly by binding to a protein on the surface of a bacterium. This action promulgates a signal throughout the immune system to bring additional cells forward to help eradicate the pathogen. Future encounters with the same pathogen will be easier to fight as B cells remain in the bloodstream and are prepared to release antibodies against those specific antigens.

Antibody Production and Custom Antibody Services

Established in 1998, ProSci Incorporated is a leading provider of high performance antibodies and custom antibody services. We have produced more than 10,000 custom monoclonal and polyclonal antibodies for researchers worldwide in academia, biotechnology, diagnostics, and pharmaceutical industries. ProSci Incorporated has developed and manufactured SARS-CoV-2 (COVID-19, 2019-nCoV) antibodies, antigens, and other reagents related to cellular entry: ACE2 receptor, TMPRSSR2 protease, and furin enzyme.We are adding new SARS-CoV-2 reagents for spike, S1, S2, nucleocapsid, membrane, envelope including llama single domain antibodies and recombinant proteins.

Operating our own USDA licensed and NIH/OLAW assured animal facility in San Diego, California, USA and performing immunological services in-house allows us to offer competitive pricing and tailor antibody production for almost any antibody need. Our responsive, results-oriented company culture enables ProSci to produce antibodies specifically for your research requirements, on a budget and timeframe that exceed expectations.

Our dedicated and experienced staff looks forward to assisting you with any aspect of the project from selecting the ideal type of antibody and host species to helping design an immunization protocol or an antigenicity-guaranteed peptide for your custom antibody project. ProSci has the experience and expertise to help you develop the antibodies you desire.