Mahnke Karsten, Johnson Theron S, Ring Sabine, Enk Alexander H
University Hospital Heidelberg, Department of Dermatology, Vossstrasse 3, D-69115 Heidelberg, Germany.
J Dermatol Sci. 2007 Jun;46(3):159-67. doi: 10.1016/j.jdermsci.2007.03.002. Epub 2007 Apr 10.
At first glance, dendritic cells (DCs) and regulatory T cells (Tregs) do not have much in common. DCs are characterized by their unsurpassed T cell stimulatory capacity, whereas Tregs are marked by the ability to suppress proliferation of effector T cells. However, only mature/activated DCs stimulate T cell proliferation, whereas immature DCs induce Tregs. This provides a means by which peripheral tolerance is maintained: in the absence of inflammation and disease, DCs encounter apoptotic cells and "self" detritus in peripheral tissues. Thus, DCs constantly sample the peripheral environment and, accordingly, the presentation of "self" by these steady state DCs results in induction of suppressive Tregs. Vice versa, Tregs are able to affect DC development, preventing maturation and inducing IL-10, as well as immunosuppressive molecules of the B7-H family, in DCs. Therefore, these novel findings establish a mutual interaction between DCs and Tregs for the upkeep of immunosuppression: immature DCs induce Tregs and inversely Tregs prepare DCs to become immunosuppressive, thereby extending the immunosuppressive function of Tregs. The possible means of cellular interactions as well as the consequences for tolerance and immunity are discussed in this review.
乍一看，树突状细胞（DCs）和调节性T细胞（Tregs）没有太多共同之处。DCs的特点是具有无与伦比的T细胞刺激能力，而Tregs的标志是能够抑制效应T细胞的增殖。然而，只有成熟/活化的DCs刺激T细胞增殖，而未成熟的DCs诱导Tregs。这提供了一种维持外周耐受的方式：在没有炎症和疾病的情况下，DCs在外周组织中遇到凋亡细胞和“自身”碎屑。因此，DCs不断对外周环境进行采样，相应地，这些稳态DCs对“自身”的呈递导致抑制性Tregs的诱导。反之亦然，Tregs能够影响DC的发育，阻止其成熟并诱导DCs产生IL-10以及B7-H家族的免疫抑制分子。因此，这些新发现建立了DCs和Tregs之间的相互作用以维持免疫抑制：未成熟的DCs诱导Tregs，反过来Tregs使DCs具有免疫抑制作用，从而扩展了Tregs的免疫抑制功能。本文综述了细胞相互作用的可能方式以及对耐受和免疫的影响。
