Regulatory T cells (Tregs) are key players of immune regulation/dysregulation both in physiological and pathophysiological settings. Despite significant advances in understanding Treg function, there is still a pressing need to define reliable and specific markers that can distinguish different Treg subpopulations. Herein we show for the first time that markers of activated Tregs [latency assoc...

The forkhead box protein 3 (FOXP3) transcription factor is highly expressed in tumor cells as well as in regulatory T cells (Tregs). It plays a tumor-enhancing role in Tregs and suppresses carcinogenesis as a potent repressor of several oncogenes. The clinical prognostic value of FOXP3 expression has not yet been elucidated. In this study, immunohistochemistry was used to investigate the progno...

This study showed that the absence of CCR7 or mesenteric lymph nodes/gut-associated lymphoid tissue did not appreciably impact total intestinal Foxp3+ regulatory T cell representation in the steady-state. However, mesenteric lymph nodes/GALT are required for normal peripherally induced Foxp3+ regulatory T cell differentiation in the small intestine, but not in the large intestine. BACKGROUND ...

Numerous studies have highlighted the importance of high-affinity interactions between T cell receptors (TCRs) and their ligands in the selection of Foxp3(+) regulatory T cells (T reg cells). To determine the role of the TCR in directing T cells into the Foxp3(+) lineage, we generated transgenic (Tg) mice expressing TCRs from Foxp3(+) cells. Initial analyses of the TCR Tg mice crossed with RAG-...

The molecular mechanism of the extrathymic generation of adaptive, or inducible, CD4(+)Foxp3(+) regulatory T cells (iTregs) remains incompletely defined. We show that exposure of splenic CD4(+)CD25(+)Foxp3(-) cells to IL-2, but not other common γ-chain cytokines, resulted in Stat5 phosphorylation and induced Foxp3 expression in ∼10% of the cells. Thus, IL-2/Stat5 signaling may be critical for F...

Dendritic cells (DCs) are specialized antigen-presenting cells that regulate both immunity and tolerance. DCs in the periphery play a key role in expanding naturally occurring Foxp3(+) CD25(+) CD4(+) regulatory T cells (Natural T-regs) and inducing Foxp3 expression (Induced T-regs) in Foxp3(-) CD4(+) T cells. DCs are phenotypically and functionally heterogeneous, and further classified into sev...

CD4(+)CD25(+) regulatory T (Treg) cell lineage commitment and expression of the transcription factor Foxp3 can be induced at the CD4(+)CD8(+) double-positive (DP) and CD4(+)CD8(?) single-positive stages of thymic development, as well as in postthymic CD4(+) T cells in peripheral lymphoid tissues. The availability of transgenic mice with Foxp3-dependent fluorochrome reporter gene expression has ...

Low Ag dose promotes induction and persistence of regulatory T cells (Tregs) in mice, yet few studies have addressed the role of Ag dose in the induction of adaptive CD4(+)FOXP3(+) Tregs in humans. To this end, we examined the level of FOXP3 expression in human CD4(+)CD25(-) T cells upon activation with autologous APCs and varying doses of peptide. Ag-specific T cells expressing FOXP3 were iden...

OBJECTIVES CD4+CD25+FOXP3+ regulatory T cells (Treg) inhibit the anti-tumour immune response and reduce the effect of cancer immunotherapy. Although studies have demonstrated that the number and suppressive activity of Treg increase with age, it is not clear whether these changes correlate with a higher incidence of tumours in the elderly. This study was designed to explore the relationship bet...

Among the signals necessary to generate CD4(+)CD25(+)FOXP3(+) T cells from CD4(+)CD25(-)FOXP3(-) T cells, a pivotal role is played by CD28. However, in humans, it is not known whether CD28 signaling independently of TCR promotes forkhead box protein 3 (FOXP3) expression and regulates CD4(+)CD25(+)FOXP3(+) T cell functions. To address this issue, starting from our previous experience, we analyze...