Antigen Recognition by T Lymphocytes
Published Online: 28 SEP 2007
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Ferrero, I., Michelin, O. and Luescher, I. 2007. Antigen Recognition by T Lymphocytes. eLS. .
- Published Online: 28 SEP 2007
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.
- T-cell activation;
- antigen recognition