Regulatory T cells (Tregs) continuously suppress autoreactive immune responses within tissues to prevent autoimmunity, yet the recirculatory behavior of Tregs between and within tissues enabling the maintenance of peripheral tolerance remains incompletely defined. Here, we quantified homing efficiency to and the dwell time of Tregs within secondary lymphoid organs (SLOs) and used intravital two-photon microscopy to measure Treg surveillance behavior of dendritic cells. Tregs homed substantially less efficiently to SLOs compared with conventional CD4+ T cells (Tconvs), despite similar expression of homing receptors. Tregs remained on average 2-3 times longer within the LN than Tconvs before exiting, and retained Tregs differed from recirculating Tregs in phenotype, motility and interaction duration with dendritic cells. Taken together, these data revealed fundamental differences in Treg versus conventional T cell in vivo recirculation and migration behaviors, identified a Treg population with prolonged LN dwell time, and provided quantitative insight into their spatiotemporal behavior within LNs.

中文翻译：

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调节性T细胞与常规CD4 + T细胞的再循环行为和淋巴结转移时间不同。

调节性T细胞（Tregs）持续抑制组织内的自身反应性免疫反应，以防止自身免疫，然而，组织之间和内部的Tregs的再循环行为使得维持外周耐受性仍未完全定义。在这里，我们量化了次级淋巴器官（SLO）内Treg的归巢效率和停留时间，并使用活体双光子显微镜测量树突状细胞的Treg监视行为。尽管归巢受体的表达相似，但与传统的CD4 + T细胞（Tconvs）相比，Tregs对SLO的归巢效率要低得多。离开前，Tregs在LN中的平均停留时间比Tconvs长2-3倍，并且保留的Tregs在表型，运动性和与树突状细胞的相互作用持续时间方面与循环Tregs不同。在一起