Plasmacytoid dendritic cells (PDCs) are key effectors in host innate immunity and orchestrate adaptive immune responses. CpG oligodeoxynucleotides (ODN) have potent immunostimulatory effects on PDCs through TLR9 recognition and signaling. Little is known about the effects of CpG ODN on human PDC-mediated T cell priming. Here we show that type B CpG ODN effectively promotes PDCs to prime allogen...

Naturally occurring Foxp3(+)CD4(+)CD25(+) T cells isolated from lungs of naive mice regulate lung allergic airway hyperresponsiveness, inflammation, levels of Th2 cytokines, and mucus production. OVA-specific (alphabetaTCR(+)) CD4(+)CD25(+) T cells suppressed ragweed-induced airway hyperresponsiveness and inflammation as did anti-TCR-treated OVA-specific CD4(+)CD25(+) T cells, suggesting that A...

Regulatory T (Tr) cells have been shown to arise in the periphery during induction of peripheral tolerance. However, the mechanism involved remains elusive. In the present study, we investigated the potential role of transforming growth factor (TGF)-beta in the peripheral induction of regulatory phenotypes in the conventional CD4(+)CD25(-) T cells. Upon priming in the presence of TGF-beta, ther...

Active suppression by T regulatory (Tr) cells plays an important role in the downregulation of T cell responses to foreign and self-antigens. Mouse CD4(+) Tr cells that express CD25 possess remarkable suppressive activity in vitro and in autoimmune disease models in vivo. Thus far, the existence of a similar subset of CD25(+)CD4(+) Tr cells in humans has not been reported. Here we show that hum...

CD4 CD25 immunoregulatory T cells play a pivotal role in preventing organ-specific autoimmune diseases and in tolerance induction to allogeneic organ transplants. We investigated whether these cells could also control graft-versus-host disease (GVHD), the main complication after allogeneic hematopoietic stem cell transplantation (HSCT). Here, we show that the few CD4 CD25 T cells naturally pres...

Previously we demonstrated that IL-15 and IL-2 control the number of memory CD8+ T cells in mice. IL-15 induces, and IL-2 suppresses the division of these cells. Here we show that CD25+CD4+ regulatory T cells play an important role in the IL-2-mediated control of memory phenotype CD8+ T cell number. In animals, the numbers of CD25+CD4+ T cells were inversely correlated with the numbers of memor...

INTRODUCTION CD25(+) FOXP3(+) CD4(+) regulatory T cells (Tregs) are induced by transforming growth factor β (TGFβ) and further expanded by retinoic acid (RA). We have previously shown that this process was defective in T cells from lupus-prone mice expressing the novel isoform of the Pbx1 gene, Pbx1-d. This study tested the hypothesis that CD4(+) T cells from systemic lupus erythematosus (SLE) ...

CD4+CD25+FOXP3+ T regulatory cells (Tregs) are pivotal for the induction and maintenance of peripheral tolerance in both mice and humans. Rapamycin has been shown to promote tolerance in experimental models and to favor CD4+CD25+ Treg-dependent suppression. We recently reported that rapamycin allows in vitro expansion of murine CD4+CD25+FoxP3+ Tregs, which preserve their suppressive function. I...

BACKGROUND In experimental models, Type 1 diabetes T1D can be prevented by adoptive transfer of CD4+CD25+ (FoxP3+) suppressor or regulatory T cells. Recent studies have found a suppression defect of CD4+CD25+(high) T cells in human disease. In this study we measure apoptosis of CD4+CD25+(high) T cells to see if it could contribute to reduced suppressive activity of these cells. METHODS AND FI...

CD4(+)CD25(+) immunoregulatory T cells play a pivotal role in preventing organ-specific autoimmune diseases and in tolerance induction to allogeneic organ transplants. We investigated whether these cells could also control graft-versus-host disease (GVHD), the main complication after allogeneic hematopoietic stem cell transplantation (HSCT). Here, we show that the few CD4(+)CD25(+) T cells natu...