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Exp Gerontol. 2002 Jan-Mar;37(2-3):455-63.

Age-associated thymic atrophy is linked to a decline in IL-7 production.

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1
Department of Immunology, ICSM at Chelsea & Westminster Hospital, 369 Fulham Road, London SW10 9NH, UK. d.andrew@ic.ac.uk

Abstract

Age-associated thymic atrophy results in a decline in T lymphocyte output and has been identified as one of the key events that precede inefficient functioning of the immune system in later life. Thymic atrophy is thought to result from a failure of the thymic microenvironment to support thymopoiesis in old age and recent evidence suggests that a decline in interleukin-7 (IL-7) expression may limit thymocyte development by restricting combinations of survival, proliferation and rearrangement of the TCRbeta chain. Using RT-PCR and the RNase protection assay, we show that the expression of IL-7 declines with age. Analysis of Connexin 43 expression, a component molecule of gap junctions, whose function is to connect epithelial cells, does not markedly decline with age. These observations suggest that a decline in IL-7 expression is not matched by a similar loss of epithelial cells. These results in conjunction with other studies lead us to speculate that IL-7 producing MHC class II positive TECs are being replaced by cells that do not have this capacity.

PMID:
11772533
[Indexed for MEDLINE]
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