|
Regulatory T cells See also Autoimmunity See also Tr1 cells It is now widely accepted that several types of regulatory cells exist, some of which are induced in response to infectious challenge and some that are considered natural regulators. Regulatory T cells are pivotal in inhibiting inappropriate activation of cell and antibody mediated immune responses against self antigen as well as innate immune responses. These regulatory T cell populations were first discovered in experimental aniaml models and subsequently indentified in humans. Subsets of Regulatory T cells Tregs can broadly be divided into T cells that appear to require antigen-specific, MHC-restricted stimulation, with subsequent secretion of cytokines that down-regulate immune responses, Tr1 and Th3 cells, which secrete IL-10 and TGF-B, respectively, or more innate reulatory cells that do not appear to require an in vivo adaptive immunization to observe their function, the CD1-restrcited NKT cells with invariant TCRs, "nonclassical" NK T cells with variant TCRs, and the CDr_CD25+ regulatory T cells. from Journal of Clincial Investigation, Volume 114, number 100 2004 Inducible regulatory T cells (Treg cells) Dendritic Cells as inducers of Tregs Natural Treg cells CD4+CD25-, CD8+, CD+CD28-, NK-T cells: are of unknown. Regulation of CD4+CD25+ T cells Microbila induction of Toll like receptors reportedly blocks the suppressive effect of CD4+CD25+ TR cells, allowing activation of pathogen specific adaptive immune responses. This block of suppressor activity was dependent in part on IL-6, which was induced by TLRs upon recognition of microbial products. |
