[Dendritic cell-regulatory T-cell interaction]

The one of the main modes of homeostasis protection is maintaining the balance between antimicrobial immunological reactions and mechanisms involved in immune response suppression. The interaction between dendritic and T cells plays a crucial role in inducing both an immune response and immunological tolerance. Dendritic cells are also able to affect the differentiation, migration, and activation of CD4+ T cells using cell-to-cell contact and/or cytokine production. The proper cytokine microenvironment can influence the induction of FoxP3 transcription factor in T cells, determining the regulatory properties of these cells. However, it is still unclear what is more substantial for Treg induction: the cytokines in the microenvironment, stimulation by a specific DC population, or the type of antigens presented by DC. Activated natural Treg as well as induced Treg cells use similar mechanisms to generate tolerance, for example by the production of such anti-inflammatory cytokines as TGF-beta or IL-10 and by direct contact with target cells. Recently, some reports have described the possibility that Treg cells lose FoxP3 expression followed by loss of suppressive function directed against proliferating T lymphocytes.