CD25+ CD4+ T cells compete with naive CD4+ T cells for IL-2 and exploit it for the induction of IL-10 production.
Int Immunol
; 17(3): 279-88, 2005 Mar.
Article
em En
| MEDLINE
| ID: mdl-15684039
ABSTRACT
Maintenance of homeostasis in the immune system involves competition for resources between T lymphocytes, which avoids the development of immune pathology seen in lymphopenic mice. CD25+ CD4+ T cells are important for homeostasis, but there is as yet no consensus on their mechanisms of action. Although CD25+ CD4+ T cells cause substantial down-regulation of IL-2 mRNA in responder T cells in an in vitro co-culture system, the presence of IL-protein can be demonstrated by intracellular staining. As a consequence of competition for IL-2, CD25+ CD4+ T cells further up-regulate the IL-2R alpha chain (CD25), a process that is strictly dependent on IL-2, whereas responder T cells fail to up-regulate CD25. Similarly, adoptive transfer into lymphopenic mice showed that CD25+ CD4+ T cells interfere with CD25 up-regulation on co-transferred naive T cells, while increasing their own CD25 levels. IL-2 sequestration by CD25+ CD4+ T cells is not a passive phenomenon but instead initiates--in conjunction with signals through the TCR--their differentiation to IL-10 production. Although IL-10 is not required for in vitro suppression, it is vital for the in vivo function of regulatory T cells. Our data provide a link explaining the apparent difference in regulatory mechanisms in vitro and in vivo.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Linfócitos T CD4-Positivos
/
Receptores de Interleucina-2
/
Subpopulações de Linfócitos T
/
Interleucina-2
/
Interleucina-10
Limite:
Animals
Idioma:
En
Revista:
Int Immunol
Assunto da revista:
ALERGIA E IMUNOLOGIA
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Reino Unido