Efficient maturation of alpha beta lineage thymocytes to the CD4+CD8+ stage in the absence of TCR-beta rearrangement.
We have produced transgenic mice that express rearranged T cell Ag receptor gamma and delta transgenes in the alpha beta lineage of thymocytes. Thymi in these mice contain normal numbers of CD4+CD8+ cells that express low levels of the TCR-gamma delta. Analysis of the delta locus in these thymi indicates that these cells are in the alpha beta lineage even though they express the TCR-gamma delta. This shows that expression of the TCR-gamma delta in early thymocytes can lead to all of the consequences that are normally mediated by the beta-chain. These consequences include maturation to the CD4+CD8+ stage, entry into the cell cycle, and cessation of beta rearrangement. Therefore, the data support a model in which formation of a functional CD3 complex on immature CD4-CD8- thymocytes leads to further development in the absence of extracellular ligand recognition. The data also show that the gamma delta vs alpha beta lineage decision is made in a manner that is independent of gamma and beta gene expression.
Kersh
G J
GJ
Department of Biology, University of California, San Diego, La Jolla 92093, USA.
Hooshmand
F F
FF
Hedrick
S M
SM
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D003001:Cloning, Molecular; D005434:Flow Cytometry; D015329:Gene Rearrangement, T-Lymphocyte / Q000235:genetics*; D015698:Genomic Library; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics*; D013950:Thymus Gland / Q000166:cytology*
D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta