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Cell. 1991 Jan 11;64(1):99-107.

Thymic selection in CD8 transgenic mice supports an instructive model for commitment to a CD4 or CD8 lineage.

Author information

1
Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032.

Abstract

Immature thymocytes, which coexpress CD4 and CD8, give rise to mature CD4+CD8- and CD4-CD8+ T cells. Only those T cells that recognize self-MHC are selected to mature, a process known as positive selection. The specificity of the T cell antigen receptor (TCR) for class I or class II MHC influences the commitment to a CD4 or CD8 lineage. This may occur by a directed mechanism or by stochastic commitment followed by a selection step that allows only CD8+, class I-specific and CD4+, class II-specific cells to survive. We have generated a mouse line expressing a CD8 transgene under the control of the T cell-specific CD2 regulatory sequences. Although constitutive CD8 expression does not affect thymic selection of CD4+ cells, selection of a class I-specific TCR in the CD8 subset is substantially improved. This outcome is consistent with a model for positive selection in which selection occurs at a developmental stage in which both CD4 and CD8 are expressed, and positive selection by class I MHC generates an instructive signal that directs differentiation to a CD8 lineage.

PMID:
1898873
DOI:
10.1016/0092-8674(91)90212-h
[Indexed for MEDLINE]

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