Idiotype

The idiotype is based upon the variable region (labeled VL and VH in the diagram.)

In immunology, an idiotype is a shared characteristic between a group of immunoglobulin or T cell receptor (TCR) molecules based upon the antigen binding specificity and therefore structure of their variable region. The variable region of antigen receptors of T cells (TCRs) and B cells (immunoglobulins) contains a complementarity determining region (CDR) with a unique amino acid structure that determines the antigen specificity of the receptor. The structure formed by the CDR is known as the idiotope. Immunoglobulins or TCRs with a shared idiotope are the same idiotype. Antibody idiotype is determined by

• Gene rearrangement
• Junctional diversity
• P-nucleotides (palindromic nucleotides at sites of single-strand breaks)
• N-nucleotides
• Somatic hypermutations

The term idiotype is sometimes used to describe the collection of multiple idiotopes, and therefore overall antigen binding capacity, possessed by an antibody.

See also

• immunoglobulin allotype
• Isotype (immunology)

External links

• MeSH Immunoglobulin+idiotypes
• Idiotype at eMedicine Dictionary
• Overview at Medical University of South Carolina
• Overview at Southern Illinois University Carbondale

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