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Antigen Recognition by T Lymphocytes

  1. Isabel Ferrero,
  2. Olivier Michelin,
  3. Immanuel Luescher

Published Online: 28 SEP 2007

DOI: 10.1002/9780470015902.a0001229.pub2

eLS

eLS

How to Cite

Ferrero, I., Michelin, O. and Luescher, I. 2007. Antigen Recognition by T Lymphocytes. eLS. .

Author Information

  1. Ludwig Institute for Cancer Research, Lausanne, Switzerland

Publication History

  1. Published Online: 28 SEP 2007

Abstract

T lymphocytes (or T cells) are thymus-derived and are key players in the adaptive cellular immunity. They recognize antigen by means of their T-cell receptor (TCR), which consist of two chains, and are surface expressed upon association with invariant CD3 units, which mediate TCR signalling. TCR, especially αβ TCR, exhibit a vast diversity, provided by the somatic rearrangement of TCR gene segments. γδ and αβ T cells exhibit important differences regarding tissue localization and antigen recognition. αβ T cells express as coreceptor CD4 or CD8. CD4+ T cells are MHC class II-restricted and comprise T helper (TH) and regulatory (Treg) T cells. CD8αβ+ T cells are MHC class I-restricted and are predominantly cytotoxic T cells (CTL). γδ T cells constitute as a link between innate and adaptive immunity. They are found frequently in epithelia (e.g. skin and intestine) and recognize nonclassical MHC class Ib molecules and diverse small nonpeptidic compounds in a coreceptor and MHC restriction independent manner.

Keywords:

  • TCR;
  • MHC;
  • CD8;
  • CD4;
  • T-cell activation;
  • antigen recognition