Document Detail


TCR down-regulation controls T cell homeostasis.
MedLine Citation:
PMID:  19801521     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
TCR and cytokine receptor signaling play key roles in the complex homeostatic mechanisms that maintain a relative stable number of T cells throughout life. Despite the homeostatic mechanisms, a slow decline in naive T cells is typically observed with age. The CD3gamma di-leucine-based motif controls TCR down-regulation and plays a central role in fine-tuning TCR expression and signaling in T cells. In this study, we show that the age-associated decline of naive T cells is strongly accelerated in CD3gammaLLAA knock-in mice homozygous for a double leucine to alanine mutation in the CD3gamma di-leucine-based motif, whereas the number of memory T cells is unaffected by the mutation. This results in premature T cell population senescence with a severe dominance of memory T cells and very few naive T cells in middle-aged to old CD3gamma mutant mice. The reduced number of naive T cells in CD3gamma mutant mice was caused by the combination of reduced thymic output, decreased T cell apoptosis, and increased transition of naive T cells to memory T cells. Experiments with bone marrow chimeric mice confirmed that the CD3gammaLLAA mutation exerted a T cell intrinsic effect on T cell homeostasis that resulted in an increased transition of CD3gammaLLAA naive T cells to memory T cells and a survival advantage of CD3gammaLLAA T cells compared with wild-type T cells. The experimental observations were further supported by mathematical modeling of T cell homeostasis. Our study thus identifies an important role of CD3gamma-mediated TCR down-regulation in T cell homeostasis.
Authors:
Lasse Boding; Charlotte Menné Bonefeld; Bodil L Nielsen; Jens Peter H Lauritsen; Marina Rode von Essen; Ann Kathrine Hansen; Jeppe Madura Larsen; Morten Milek Nielsen; Niels Odum; Carsten Geisler
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of immunology (Baltimore, Md. : 1950)     Volume:  183     ISSN:  1550-6606     ISO Abbreviation:  J. Immunol.     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-10-05     Completed Date:  2009-11-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985117R     Medline TA:  J Immunol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4994-5005     Citation Subset:  AIM; IM    
Affiliation:
Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antigens, CD3 / genetics,  immunology*,  metabolism
Apoptosis / immunology
Down-Regulation / immunology
Homeostasis / immunology*
Mice
Mice, Inbred C57BL
Mice, Mutant Strains
Receptors, Antigen, T-Cell / immunology*,  metabolism
T-Lymphocytes / immunology*,  metabolism
Thymus Gland / immunology*,  metabolism
Chemical
Reg. No./Substance:
0/Antigens, CD3; 0/CD3 antigen, gamma chain; 0/Receptors, Antigen, T-Cell

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