Table of Contents
What is an Epitope? Epitope Mapping
An epitope is the specific site on an antigen to which an antibody binds. Epitope mapping is the determination of the specific location of an epitope on an antigen. An epitope is a part of an antigen that is recognized by an antibody. However the epitope is usually a specific region of the antigen that is bound by the antibody.
What is an Antigenic Determinant?
An antigenic determinant is a fragment of a protein or carbohydrate molecule that recognized as a foreign invader by the immune system. These determinants are also called epitopes. The body’s immune system produces antibodies that specifically recognize and attach to these epitopes.
Types of Epitope
Epitopes are specific regions of an antigen that are recognized by an antibody. The term epitope derived from the Greek word “epithetes” meaning “to describe.” The antigenicity of an epitope is determined by the chemical structure of the antigen and the antibody.
There are three types of epitopes:
1. Structural epitopes are located on the surface of the antigen and are responsible for the antigen’s physical properties.
2. Functional epitopes are responsible for the antigen’s biological function.
3. T-cell epitopes recognized by T cells and are important in the immune response.
Antibodies Functions
They are proteins that produced by the immune system in response to the presence of an antigen. Antibodies bind to the antigen, which helps to neutralize it and also prevent it from causing harm. Antibodies can also signal the immune system to destroy the antigen.
Epitope Structure
Epitopes are specific regions on the surface of an antigen that interact with the corresponding region on an antibody. The epitope structure determined by the chemical and spatial arrangement of the amino acids in the antigen that interact with the antibody. The epitope structure is important for both the antibody and the antigen because it determines the specificity of the interaction.
1. T Cell Epitopes
T cell epitopes are parts of proteins or other molecules that recognized by T cells. They are important for the immune system because they allow T cells to identify and destroy pathogens or cancer cells. T cell epitopes are typically short sequences of amino acids that bound by the T cell receptor.
2. B Cell Epitopes
A B cell epitope is a specific region on an antigen that recognized by a B cell. The epitope is usually a short peptide sequence, and it is also important for the antigen to displayed on the surface of a cell in order for the B cell to recognize it. The B cell will then produce antibodies that are specific for that epitope.
Substances that Act as Antigens
Bacteria, viruses, and other microorganisms are the most common antigens. These organisms constantly exposed to the body’s immune system, and also the immune system is constantly creating antibodies to fight them. Other antigens include toxins, blood products, and also the cancer cells.
Epitope-based Vaccines
- Epitope-based vaccines are a type of vaccine that uses specific peptides (pieces of proteins) from a virus, bacteria, or other pathogen to help the body build immunity to that pathogen. However these vaccines designed to target certain parts of a pathogen that are specific to that pathogen and not found in other organisms. This makes them an effective way to specifically target a pathogen and also helps to improve the effectiveness of a vaccine.
- One example of an epitope-based vaccine is the HPV vaccine. Therefore the HPV vaccine designed to target a specific peptide found on the surface of the HPV virus. This peptide not found on the surface of any other virus and is important for the HPV virus to infect cells. By targeting this peptide with a vaccine, the body can build immunity to the HPV virus.
