Abstract:
:Using GFP to mark recent thymic emigrants (RTEs) in mice carrying a GFP transgene driven by the recombination-activating gene 2 promoter, we demonstrate that RTEs are readily detectable even in 2-year-old mice, despite the fact that the proportion of the peripheral T cell pool comprised of RTEs declines with age. Although the number of RTEs decreases after reaching a peak at 6 weeks of age, thymic output as a function of thymic size is surprisingly age-independent. The CD4:CD8 ratio of RTEs declines with age, partly because of a striking decrease in steady-state proliferation of CD4+ RTEs in older mice. RTEs in aged mice undergo phenotypic maturation in the lymphoid periphery with delayed kinetics compared with young mice. RTEs from aged mice secrete less IL-2, proliferate less well, and achieve only weak expression of early-activation markers compared with more mature naïve peripheral T cells from the same mice. The proportion of GFP- cells in the CD4+ and CD8+ thymic compartments increases with age, partly as a result of leakiness in the aged thymus, allowing reentry of naïve peripheral T cells.
journal_name
Proc Natl Acad Sci U S Aauthors
Hale JS,Boursalian TE,Turk GL,Fink PJdoi
10.1073/pnas.0601040103subject
Has Abstractpub_date
2006-05-30 00:00:00pages
8447-52issue
22eissn
0027-8424issn
1091-6490pii
0601040103journal_volume
103pub_type
杂志文章abstract::Deletion derivatives of the maize transposable element Activator (Ac) were constructed in vitro and inserted into a kanamycin resistance gene. These constructions were then introduced into tobacco protoplasts derived from plants previously transformed with Ac. The ability of each deletion derivative to excise was meas...
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