Recombinant-activating gene 2 (RAG-2-/-) T cell receptor-transgenic mice repeatedly injected with the superantigen staphylococcal enterotoxin A entered a tolerant state in which splenic CD4+ T cells produced little interleukin (IL)-2, interferon gamma, or IL-4. This state resulted from a combination of both clonal anergy and cytokine-mediated immunosuppression. The anergy persisted for at least...

Sarcoidosis is characterized by extensive local inflammation (granuloma, cytokine secretion) associated with anergy (poor response to antigens in vitro and in vivo). We postulated that this paradoxical situation would correspond to a disequilibrium between effector and regulatory T lymphocytes (T reg cells). We show that CD4+CD25(bright)FoxP3+ cells accumulate at the periphery of sarcoid granul...

T he ability to distinguish between self versus nonself is the most salient feature of the immune system. It is of vital importance for the immune system to mount vigorous humoral and cellular responses to foreign antigens. On the other hand, it is equally important for the immune system to be tolerant against self-antigens. Tolerance can be maintained either by physical elimination (clonal del...

Interaction of CD28/CTLA-4 on T cells with B7 on antigen-presenting cells constitutes an important costimulatory signal for T cells and is responsible for cyclosporin A-resistant interleukin 2 (IL-2) gene expression and potentially also for prevention of anergy induction after T cell receptor triggering. In this paper, we demonstrate that addition of a monoclonal antibody to B7, which blocks B7...

The importance of regulatory T cells in immune tolerance is illustrated by the human immune dysregulatory disorder IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked), caused by a lack of regulatory T cells due to decreased or absent expression of Foxp3. Although the majority of work on regulatory T cells has focused on their ability to suppress T cell responses, the developm...

T cell receptor (TCR) engagement in the absence of costimulation induces the calcium-dependent upregulation of a program of gene expression that leads to the establishment of T cell anergy. Casp3 is one of the genes activated during anergy induction. Here we show that caspase 3 is required for the induction of T cell unresponsiveness. Suboptimal T cell stimulation induced caspase 3 activation, ...

Split anergy represented by delayed-type hypersensitivity skin reaction to tuberculin, but not to leprosin, is known to occur in a distinct proportion of leprosy patients. The mechanism was originally attributed to Mycobacterium leprae-specific suppression of T cells toward common mycobacterial antigens. This study ascertained an alternative explanation, attributing the phenomenon to selective ...