Suppressor activity of anergic T cells induced by @entity688 -treated @entity1 dendritic cells: association with XXXX - and @entity4386 -dependent G1 arrest of the cell cycle regulated by @entity13525 .

@entity1 @entity404 @entity379 @entity13525 @entity1199 @entity688 @entity4386 @entity995
We have previously shown that @entity1 @entity688 -treated dendritic cells (DC) induce an antigen-specific anergy in @entity404 + T lymphocytes. These anergic T cells are characterized by an inhibited proliferation, a reduced production of @entity1199 , and additionally display antigen-specific suppressor activity. In this study we investigated the mechanisms underlying the anergic state and regulatory function of these T cells. We did not observe enhanced rates of programmed cell death of anergic @entity404 + suppressor T cells compared to T cells stimulated with mature DC. Cell cycle analysis by DNA staining and Western blot experiments revealed an arrest of anergic @entity404 + T suppressor cells in the G1 phase. High levels of the @entity1199 -dependent cyclin-dependent kinase (cdk) inhibitor @entity13525 were found in anergic @entity404 + suppressor T cells resulting in an inhibited activation of @entity995 protein and an arrest of cell cycle progression in the G1 phase. Addition of @entity1199 , but not blocking of the @entity4386 pathway restored the proliferation of the suppressor T cells. In contrast, both treatments induced a down-regulation of @entity13525 and acomplete inhibition of the antigen-specific regulatory function as demonstrated by high proliferation and enhanced @entity379 production of co-cultured T cells. Further experiments demonstrated that p27Kip-expressing regulatory @entity404 +CD25+ T cells did not contribute to induction of T cell anergy in this model. Our data show that regulatory function of anergic @entity404 + suppressor T cells is associated with an arrest in the G1 phase of the cell cycle mediated by increased levels of the @entity1199 and @entity4386 -dependent cdk inhibitor @entity13525 .
