BACKGROUND Regulatory T cells (Tregs) were shown to be central in maintaining immunological homeostasis and preventing the development of autoimmune diseases. Several subsets of Tregs have been identified to date; however, the dynamics of the interactions between these subsets, and their implications on their regulatory functions are yet to be elucidated. METHODOLOGY/PRINCIPAL FINDINGS We emp...

Although regulatory T cells (Tregs) have been detected in clinically apparent and experimentally induced tumors, the significance of their presence is obscured because past studies examined late-stage tumors that had formed in immunocompetent hosts and thus had evolved mechanisms to escape immunologic recognition and/or elimination. Herein, we report the first comparative analysis of the antitu...

Recent studies have demonstrated that activated peripheral alphabeta TCR+ CD3+ CD4- CD8- NK1.1- (double-negative, DN) regulatory T cells (Tregs) from both mice and humans are able to down-regulate immune responses in vitro and in vivo. However, the origin and developmental requirements of functional DN Tregs remain unclear. In this study, we investigated the requirement for CD8 expression as we...

Background: Atherosclerosis is a multifactorial disorder with chronic inflammatory conditions in which immune cells play a significant role in its pathogenic process. Regulatory T cells (Treg), as a part of immune system, are involved in controlling autoimmune and inflammatory diseases. Quantitative and/or functional alteration of Tregs has been shown to play an atheroprotective role and may al...

Activated T cells can acquire membrane molecules from APCs through a process termed trogocytosis. The functional consequence of this event has been a subject of debate. Focusing on transfer of peptide-MHC class II (MHC-II) complexes from APCs to CD4(+) T cells after activation, in this study we investigated the molecule acquisition potential of naturally occurring regulatory T cells (Tregs) and...

CD4+CD25+ T regulatory cells (Tregs) prevent autoimmune disease, yet little is known about precisely where they exert their influence naturally in a spontaneous autoimmune disorder. Here, we report that Tregs and T effector cells (Teffs) coexist within the pancreatic lesion before type 1 diabetes onset. We find that BDC2.5 T cell receptor transgenic animals contain a small subset of FoxP3 posit...

CD4+ regulatory T cells (Tregs) mediate immune tolerance in laryngeal squamous cell carcinoma (LSCC). However, Tregs are functionally heterogeneous. Recently, we reported that three distinct Treg subsets (resting Tregs, activated Tregs and cytokine-secreting CD45RA-Foxp3lowCD4+ T cells) vary in the peripheral circulation of patients with head and neck squamous cell carcinoma (HNSCC); however, t...

BACKGROUND Donor-specific blood transfusion (DST) prior to solid organ transplantation has been shown to induce long-term allograft survival in the absence of immunosuppressive therapy. Although the mechanisms underlying DST-induced allograft tolerance are not well defined, there is evidence to suggest DST induces one or more populations of antigen-specific regulatory cells that suppress allogr...

Complex interactions between effector T cells and Foxp3(+) regulatory T cells (Treg) contribute to clinical outcomes in cancer, and autoimmune and infectious diseases. Previous work showed that IL-12 reversed Treg-mediated suppression of CD4(+)Foxp3(-) T cell (Tconv) proliferation. We and others have also shown that Tregs express T-bet and IFN-γ at sites of Th1 inflammation and that IL-12 induc...

NO is a free radical with pleiotropic functions. We have shown earlier that NO induces a population of CD4(+)CD25(+)Foxp3(-) regulatory T cells (NO-Tregs) that suppress the functions of CD4(+)CD25(-) effector T cells in vitro and in vivo. We report in this study an unexpected finding that NO-Tregs suppressed Th17 but not Th1 cell differentiation and function. In contrast, natural Tregs (nTregs)...