In immunology, an idiotype is a shared characteristic between a group of immunoglobulin or T-cell receptor molecules based upon the antigen binding specificity and therefore structure of their variable region.

What is an idiotypic network?

The idiotype network is a complex cascade of antibodies. Normally, after antibodies are produced in response to antigen, antiidiotypic antibodies arise. These anti-idiotypes can bind to all antibodies bearing the specific idiotypic determinant, independent of their antigenic specificity.

What antigen means?

An antigen is any substance that causes your immune system to produce antibodies against it. This means your immune system does not recognize the substance, and is trying to fight it off. An antigen may be a substance from the environment, such as chemicals, bacteria, viruses, or pollen.