Since total numbers of migrated CD4+ T cells did not differ between HD and RR-MS samples, lower Treg percentages under non-inflammatory Pexidartinib concentration conditions can be excluded to be due to increased migration of non-Treg. In line with our data on murine Treg transmigration, human HD Treg displayed consistent basolateral accumulation in the absence of endothelial cells. Higher Treg motility compared to non-Treg has previously been suggested as a mechanism of suppression of T effector cell function

as Treg were shown to be superior to TH cells in establishing close contact to dendritic cells, subsequently inhibiting their full maturation 27. Our finding of an augmented Treg motility in HD therefore is very well in line with this previous data. Furthermore, our observation of a migratory dysfunction of MS patient derived Treg introduces the idea that the presumed “regulatory deficiency” of CD4+ Treg in MS could at least be partially due to impairment in Treg motility. Our study provides first evidence of augmented overall cell motility as a constitutive feature of both Pembrolizumab order murine and human naturally occurring regulatory T cells. Adhesion ligand and chemokine receptor patterns expressed by Treg and their non-regulatory counterparts presumably determine

site-specific homing and have recently been a matter of substantial interest. Their innate cell motility, however, forms the basis of transendothelial diapedesis to and locomotion within any tissue and has been completely neglected in the past. Our data demonstrate Depsipeptide mouse an innate migratory superiority of murine and human Treg over naïve non-Treg. This migratory advantage should contribute to the role of Treg in maintaining tissue immune homeostasis and CNS immune surveillance.

However, this can be disturbed under conditions of autoimmunity, as demonstrated for MS patient-derived Treg. Albeit speculative, our findings could have relevance for the understanding of early lesion development and remitting phases during MS course. Twelve patients (9 female, 3 male) suffering from clinically definite RR-MS according to the revised McDonald diagnostic criteria 28 were enrolled in this study. All patients were in a stable phase of the disease, with relatively low scores on Kurzke’s expanded disability status scale (EDSS<3.5) and neither currently nor previously receiving any immunomodulatory treatment (age: 41.7±12.6 years, disease duration: 4.9±6.6 years, EDSS: 1.4±0.8). Ten HD (7 female, 3 male) with no previous history of neurologic disease served as controls (age: 34.1±12.2 years). There was no significant difference in age and gender distribution between patients with MS and healthy individuals. The study was approved by the local ethics committee and informed written consent was obtained from all participants. Six-wk-old female C57BL/6 mice were obtained from Harlan Laboratories.