Peripheral Treg cells

Peripheral Treg cells CD4+,CD25+r FoxP3 /FoxP3+... 

The generation of peripheral Treg cells may result in the establishment of homeostasis after its disruption. Examples include infection, autoimmune diseases, certain forms of cancers and immunodeficiency syndrome. The mechanisms by which peripheral Treg cells induce self-tolerance and homeostasis may involve cytokines or cell-cell interaction. The cytokines IL-10 and TGF-(3 and molecules such as CTLA-4 are involved in the effector mechanisms of Treg cells. The indirect effects of Treg cells may be mediated via APCs or NK cells. More specifically, the assembly of immunological synapse between APCs and effector cells is modulated by Treg cells, which may be mediated via direct or indirect mechanisms. 

Importantly, although Th2 cells are responsible for the development of allergic diseases, Thl cells may contribute to chronicity and effector phase in allergic diseases [30-33,38,39]. Distinct Thl and Th2 2 subpopulations of T cells counterregulate each other and play a role in distinct diseases [34,35]. In addition, recent studies have demonstrated that peripheral T-cell tolerance is crucial for a healthy immune response and successful treatment of allergic disorders [40-42]. A further subtype ofT cells, with immunosuppressive function and cytokine profiles distinct from either Thl and Th2 cells, termed regulatory/suppressor T cells (Treg), has been existence in humans has been demonstrated [41,... 

In addition to Thl cells, Treg cells are able to inhibit the development of allergic Th2 responses [47] and play a major role in allergen-SIT [41,42]. This review will examine allergen-specific peripheral tolerance mechanisms in humans and discuss novel ways of T-cell suppression. 

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