Unique phenotype of human tonsillar and in vitro-induced FOXP3+CD8+ T cells.
J Immunol
; 182(4): 2124-30, 2009 Feb 15.
Article
em En
| MEDLINE
| ID: mdl-19201865
ABSTRACT
Forkhead box p3 (FOXP3) is known to program the acquisition of suppressive capacities in CD4(+) regulatory T cells (Treg), whereas its role in CD8(+) T cells is unknown. The current study investigates whether FOXP3 also acts as a Treg master switch in peripheral blood and tonsillar CD8(+) T cells. Single-cell analyses reveal the existence of a FOXP3(+)CD8(+) population in human tonsils, whereas FOXP3(+)CD8(+) T cells are rarely detected in peripheral blood. Tonsillar FOXP3(+)CD8(+) T cells exhibit a Treg phenotype with high CTLA-4 and CD45RO and low CD127 and CD69 expression. Interestingly, the tonsillar FOXP3(+)CD8(+) T cells are mostly CD25(negative) and some cells also express the proinflammatory cytokines TNF-alpha, IFN-gamma, or IL-17A. Particularly, IL-17A-expressing cells are present among FOXP3(+)CD8(+) T cells. Even though FOXP3 expression is at the detection limit in peripheral blood CD8(+) T cells ex vivo, it can be induced in vitro in naive CD8(+) T cells by polyclonal stimulation. The induced FOXP3(+)CD8(+) T cells are predominantly CD25(high) and CD28(high) and similar to tonsillar cells, they produce high levels of TNF-alpha, IFN-gamma, and granzyme B. However, IL-4 expression is mutually exclusive and IL-17A expression is not detectable. These FOXP3(+)CD8(+) T cells suppress the proliferation of CD4(+) T cells in cocultures, while showing no direct cytotoxic activity. In conclusion, the current study characterizes FOXP3-expressing CD8(+) T cells from human tonsils and shows that in vitro activation leads to FOXP3 expression in CD8(+) T cells and gain of suppressive activity.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Tonsila Palatina
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Ativação Linfocitária
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Subpopulações de Linfócitos T
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Linfócitos T CD8-Positivos
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Fatores de Transcrição Forkhead
Limite:
Humans
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article