Send to

Choose Destination
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

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


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.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center