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T cell receptor genetics

Francisco A Bonilla, MD, PhD
Section Editor
Luigi D Notarangelo, MD
Deputy Editor
Elizabeth TePas, MD, MS


The genetics of the T cell receptor (TCR) and the process of assembly of mature TCR genes from gene segments during T cell development in the thymus are discussed here. T cell development and the cellular immune response are reviewed separately (see "Normal B and T lymphocyte development" and "The adaptive cellular immune response"). The International Immunogenetics Information System website is a website devoted to immunogenetics [1].


There are two types of TCRs (see "Normal B and T lymphocyte development"):

The majority (85 percent or more) of peripheral blood T cells bear a heterodimeric receptor made of two chains called alpha and beta (figure 1). This form of the TCR is also called TCR2.

The minority of circulating T cells bear a different type of TCR made up of two chains, called gamma and delta (TCR1). However, T cells expressing TCR1 may predominate in some tissues (eg, intestinal mucosa).

As with immunoglobulins, each TCR chain is encoded by multiple rearranging gene segments. The rearrangement process leads to diversification of the assembled genes through differences in the manner in which gene segments are joined in each cell undergoing its own unique rearrangement events. (See "Structure of immunoglobulins".)

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Literature review current through: Nov 2017. | This topic last updated: Dec 20, 2016.
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