Continued maturation of thymic emigrants in the periphery.
Developing thymocytes are selected for recognition of molecules encoded by the major histocompatibility complex, purged of self-reactive cells and committed to either the CD4 or CD8 lineage. The 1% of thymocytes that complete these tasks emigrate and join the population of peripheral lymphocytes. Whether T cell maturation is complete at the time of thymic exit has been a subject of debate. Using mice transgenic for green fluorescent protein driven by the recombination activating gene 2 promoter to identify recent thymic emigrants, we now show that T cell differentiation continues post-thymically, with progressive maturation of both surface phenotype and immune function. In addition, the relative contribution of CD4 and CD8 recent thymic emigrants was modulated as they entered the peripheral T cell pool. Thus, T cell maturation and subset contribution are both finalized in the lymphoid periphery.
Department of Immunology, University of Washington, Seattle, Washington 98195-7650, USA.
Tamar E
TE
Boursalian
Jonathan
J
Golob
David M
DM
Soper
Cristine J
CJ
Cooper
Pamela J
PJ
Fink
D000818:Animals; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D017930:Genes, Reporter; D051379:Mice; D008822:Mice, Transgenic; D013950:Thymus Gland / Q000166:cytology / Q000502:physiology*; D013997:Time Factors
D004268:DNA-Binding Proteins; C499308:Rag2 protein, mouse; C064655:V(D)J recombination activating protein 2