Highly efficient selection of CD4 and CD8 lineage thymocytes supports an instructive model of lineage commitment.
We undertook a kinetic analysis of the generation of mature T cells in TCR and coreceptor transgenic mice using BrdU labeling. We observed that the selection efficiency of mature CD4-CD8+ and CD4+CD8- thymocytes could be as high as 40% and 90% of CD4+CD8+ precursors, respectively. The surprisingly high efficiency of selection favors an instructional model of lineage commitment and is incompatible with a stochastic model in which the efficiency of selection would be no greater than 100% in both lineages combined.
Itano
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A
Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA.
Robey
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E
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology*; D016827:CD8 Antigens / Q000235:genetics; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology*; D002453:Cell Cycle; D002454:Cell Differentiation; D019070:Cell Lineage; D017637:Clonal Deletion / Q000502:physiology*; D004261:DNA Replication; D018655:Lymphocyte Count; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018448:Models, Immunological; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology
D016827:CD8 Antigens; D011948:Receptors, Antigen, T-Cell