Format

Send to

Choose Destination
J Immunol. 1998 Apr 15;160(8):3883-90.

Posttranslational regulation of TCR Valpha allelic exclusion during T cell differentiation.

Author information

1
Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA.

Abstract

We have previously shown that phenotypic allelic exclusion of TCR alpha-chain is functional only in mature thymocytes. A significant proportion of immature thymocytes (TCRlow) express more than one cell surface alpha-chain, but mature thymocytes (TCRhigh) show phenotypic allelic exclusion and express only a single alpha-chain. We have analyzed thymocytes for both surface and intracellular alpha-chain expression and find that the majority of mature thymocytes express a second alpha-chain intracellularly. This result is predicted by a model in which the developmentally regulated allelic exclusion of the TCR alpha-chain is caused by competition between alpha-chains for the beta-chain rather than by models in which one alpha-chain is down-regulated or in which selection favors cells with only a single alpha-chain species. Changes in the relative amounts of alpha- and beta-chains available for pairing may therefore allow competition between the two alpha-chains for the beta-chain. Peripheral T cells also frequently express second alpha-chains in the cytoplasm (18-27%), despite a rather low frequency of dual alpha-chain expression on the cell surface (2-4%). The frequency of nonsurface expressed alpha-chains is reduced somewhat compared with thymocytes, indicating that an additional level of control of allelic exclusion operates during the maturation of peripheral T cells.

PMID:
9558094
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center