We recently identified CD8+CD122+ regulatory T cells that directly control CD8+ and CD4+ cells without intervention of APCs. In this study, we investigated the effector mechanism of CD8+CD122+ regulatory T cells by using an in vitro regulation system. The profile of cytokine expression revealed that IL-10 was predominantly produced by CD8+CD122+ cells, whereas other cytokines were similarly expressed in CD8+CD122+ cells and CD8+CD122− cells. Suppression of both proliferation and IFN-γ production by CD8+CD122− cells by CD8+CD122+ cells was blocked by adding anti-IL-10 Ab to the culture but not by adding anti-TGF-β Ab. When IL-10 was removed from the conditioned medium from CD8+CD122+ cells, the conditioned medium no longer showed regulatory activity. Finally, CD8+CD122+ cells from IL-10-deficient mice had no regulatory activity in vitro and reduced regulatory activity in vivo. Our results clearly indicate that IL-10 is produced by CD8+CD122+ cells and mediates the regulatory activity of these cells.

The importance of CD8 1 CD122 1 Treg in the maintenance of immune homeostasis has been previously demonstrated in mice. Because the expression pattern of CD8 and CD122 in humans is different from that in mice, human CD8 1 Treg that correspond to the murine CD8 1 CD122 1 Treg have not been identified. In this study, we performed DNA microarray analyses to compare the gene expression profiles of CD8 1 CD122 1 cells and CD8 1 CD122 À cells in mice and found that CXCR3 was preferentially expressed in CD8 1 CD122 1 cells. When we analyzed the expression of CD122 and CXCR3 in murine CD8 1 cells, we observed a definite population of CD122 1 CXCR3 1 cells. CD8 1 CXCR3 1 cells in mice showed similar regulatory activities to CD8 1 CD122 1 cells by in vivo and in vitro assays. While CD8 1 CD122 1 CXCR3 1 cells are present in mice, CD8 1 CXCR3 1 cells, but not CD8 1 CD122 1 cells, are present in humans. In the in vitro assay, human CD8 1 CXCR3 1 cells showed the regulatory activity of producing IL-10 and suppressing IFN-c production from CD8 1 CXCR3 À cells. These results suggest that human CD8 1 CXCR3 1 T cells are the counterparts of murine CD8 1 CD122 1 Treg.Key words: CD8 cells . Cytokine receptors . Human . Treg IntroductionMaintenance of immune homeostasis is of paramount importance. The immune system, which fights pathogenic microorganisms invading the body, also can damage the host organism, i.e. autoimmune diseases and allergies. Thus, the immune reaction must be strictly regulated by multiple mechanisms, including professional regulatory cells. Such professional regulatory cells are mostly included in T cells that are thought to be ''the control tower'' of the immune system. There may be no doubt that an extraordinary progression of the research of Treg in this decade has been led by the discovery of CD4 1 CD25 1 naturally arising Treg [1][2][3][4]. Because T cells respond to some specific antigen, it is no wonder that one may dream of antigen-specific Treg that strictly suppress some specific immune response but do not affect other immune responses, and such an idea has also pushed the research of Treg. Mature T cells are generally divided into two populations by their cell-surface markers, CD4 1 and CD8 1 , and normal immune response is achieved by a good balance of CD4 1 and CD8 1 cells. Although Treg are also thought to distribute in both CD4 1 and CD8 1 populations, the research of Treg is skewed towards those in CD4 1 population.We originally identified CD8 1 CD122 1 Treg and proved their importance in the maintenance of immune homeostasis in vivo [5]. CD8 1 CD122 1 Treg are categorized into Treg of naturally arising type. One benefit to handle Treg of naturally arising type is that they enable us to do prospective investigation and to expect application of these cells for the treatment of immunebased disorders. For instance, we may be able to collect naturally arising Treg that are promised to become functional regulatory cells from patients suffering from immune-based intractable disease, expand them in so...

We identified CD8+CD122+ regulatory T cells (Tregs) and demonstrated their importance in the maintenance of immune homeostasis and in the recovery from experimental autoimmune encephalomyelitis. In this paper, we show that CD8+CD122+ Tregs effectively prevent and cure colitis in a mouse model. In our experiments, colitis was induced in lymphocyte-deficient RAG-2−/− mice by transferring CD4+CD45RBhigh cells that were excluded with CD4+ Tregs. Cotransfer of CD8+CD122+ cells clearly suppressed the development of colitis, and this suppressive effect was similar to that of CD4+CD45RBlow cells that were mostly CD4+ Tregs. CD8+CD122+ cells obtained from IL-10−/− mice were unable to suppress colitis, indicating that IL-10 is an important effect-transmitting factor in the suppression of colitis. CD8+CD122+ cells showed a suppressive effect when they were transferred 4 wk after CD4+CD45RBhigh cells, indicating the therapeutic potential of CD8+CD122+ cells. A mixture of CD8+CD122+ cells and CD4+CD45RBlow cells was far more effective than single Tregs, indicating the synergistic effect of these Tregs. These overall findings demonstrate the potential role of CD8+ Tregs, and possibly together with CD4+ Tregs, in the medical care of inflammatory bowel disease patients.

IntroductionThe balance between T helper 17 (Th17) and regulatory T cells (Treg) is a new paradigm in the pathogenesis of systemic lupus erythematosus (SLE). Currently, there are no drugs that able to modulate Th17/Treg balance specifically in SLE. Curcumin is a bioactive agent that has a specific action against hyperproliferative cells. However, its role in modulating Th17/Treg balance in SLE is still unknown. This research aimed to investigate the role of curcumin in modulating Th17/Treg balance on CD4+ T cell cultures of SLE patients.Material and methodsCD4+ T cells from SLE 6 untreated patients and 6 healthy subjects were collected, stimulated with Th17 differentiating factors, and curcumin 0.1 and 1 µg/ml was added on cultures. After 72 hours incubation, cells were harvested and measured for Th17 and Treg percentages using flow cytometry and interleukin-17A (IL-17A) and transforming growth factor-β1 (TGF-β1) levels using ELISA.ResultsAdministration of low doses of curcumin (0.1 and 1 µg/ml) could decrease Th17 percentages (p = 0.000 and p = 0.000 compared to control), reduce IL-17A productions (p = 0.000 and p = 0.000 compared to control), increase Treg percentages (p = 0.001 and p = 0.000 compared to control), and increase TGF-β1 productions (p = 0.001 and p = 0.000 compared to control) on CD4+ T cells of SLE patients. Interestingly, these effects were not reproduced on CD4+ T cells cultures of healthy subjects.ConclusionsThese data suggest that curcumin can modulate Th17/Treg balance specifically on CD4+ T cells of SLE patients without affecting healthy subjects.

Naive T cells do not proliferate but remain alive in vivo. In contrast, naive T cells rapidly die in an in vitro culture, suggesting that some factors that are present at the sites of naive T cell circulation in vivo but missing in the bovine serum-containing culture medium, are necessary for their survival. The present study was designed to search for such factors. By functional screening of the cDNA library from murine lymph nodederived stromal cells (LNS) that effectively support the survival of naive T cells, we found that nascent polypeptide-associated complex (a-NAC) promoted T cell survival. A conditioned medium derived from culture supernatant of Cos7 cells transfected with a-NAC gene supported T cell survival, indicating that a-NAC induced production of soluble factor(s) that were secreted into the medium. By examining the products that were cloned from a functional screening of the cDNA library from a-NAC-transfected NIH3T3 cells but were not detected in that from control vector-transfected cells, galectin-1 was found as a soluble factor in the conditioned medium of the LNS. Our study demonstrates the novel role of galectin-1 as a soluble factor that functions to maintain naive T cell survival without inducing cell proliferation.

BackgroundIndonesian mistletoe grows on various trees. Mango Mistletoes (Dendrophthoe pentandra) is one type of mistletoe that grown on mango tree (.benalu mangga in bahasa Indonesia). Our study used mistletoe as a parasitic plant that has been used for traditional medicine. It has been known that Dendrophtoe pentandra extract (DPE) anti-inflammatory and anticancer. Furthermore, it is necessary to follow-up study in vivo to evaluate the response to treatment of new cancer therapeutic agents. This research aimed to determine the levels of IL-22, myeloperoxide (MPO), proliferation and wild-type p53 expression after the administration of DPE to murine models of CAC.MethodsMouse colitis associated colon cancer (CAC) was induced firstly by azoxymethane (AOM) and followed by administration of drinking water containing 5 % dextran sodium sulfate (DSS) in a cycle protocol, each cycle consisted of seven days of 5 % DSS in the drinking water and followed by seven days of regular water. This study consists of five treatment groups: I was treated water only (control), II was administrated by (DSS only, without DPE), (III-V) were administrated by DPE (125 mg/kg BW, 250 mg/kg BW and 500 mg/kg BW) respectively. The administrated of DPE were started from the 8th weeks, were continued until 21 weeks. At the end of 21 weeks of the experiment, mice were sacrificed, colon tissue was removed, and then subjected to ELISA, flow cytometry, real-time PCR and histology examination.ResultsAdministration of DPE 250 mg/kgBW significantly reduce the levels of IL-22 and MPO compared with DSS only group (p < 0.001; p < 0.001). Colonic epithelial cells proliferation of group IV (DPE 250 mg/kgBW) were significantly lower than III and V groups. There was no significant change in the S phase in mice were treated DPE 125 mg/kg BW and 500 mg/kg BW, while administration of DPE 250 mg/kg BW was able to increase the percentage of cells in S phase. The expression of mRNA p53 was up regulated in mice received DPE 125 mg/kg BW.ConclusionThese findings indicate that the DPE could inhibit colonic epithelial cells proliferation through p53 pathway independently. This study also showed that DPE could be potential sources of new therapy.

BackgroundMango mistletoes Dendrophthoe pentandra (MMDP) extract has attracted interest due to its pharmacological properties, including gastro protective effects. The aim of this study was to investigate whether MMDP extract could increase Foxp3 regulatory T cells and inhibits development of Th17 cells.MethodsColitis was induced in Balb/c mice by rectal administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS). The mice were randomly divided into five groups comprising group1 receiving vehicle (the negative control), group 2–5 receiving TNBS, group 3–5 orally receiving either MMDP extract 150, 300 and 600 mg/kgBW for 7 days after TNBS administration. On day 8 of the experiment, the colon tissues were removed for histological examination, cytokine and myeloperoxidase (MPO) measurement. T-cells sub-population in mesenteric lymph nodes were analyzed by flow cytometer.ResultsMMDP extract potently suppressed colon shortening and MPO in mice with TNBS-induced colitis. Administration of the extract significantly decreased the severity of TNBS-induced colitis in a dose-dependent manner. The extract significantly attenuated the loss of body weight (p < 0.05). These effects were associated with a remarkable amelioration of the disruption of the colonic architecture, significant reduction of the colonic MPO (p < 0.05). The extract lowered the levels of Th17-associated cytokines but increased the production of Treg-associated cytokines in mesenteric lymph node cells.ConclusionOur results suggest that MMDP has the therapeutic potential to ameliorate TNBS-induced colitis symptoms revealed by histological change and inhibit IL-17 production.

The aim of this study was to determine the role of vitamin A in modulating T helper 17 (Th17) and regulatory T cell (Treg) balance in systemic lupus erythematosus (SLE) patients. Sixty-two female SLE patients and sixty-two female controls were measured for vitamin A levels from serum by enzyme-linked immunosorbent assay (ELISA) and percentages of Th17 and Treg from peripheral blood mononuclear cells (PBMC) by flow cytometry. We also performed an in vitro study to evaluate the effects of retinoic acid treatment (0, 0.1, 0.2, and 0.3 μg/ml) in modulating Th17/Treg balance in CD4(+) T cell culture from hypovitaminosis A SLE patients. Th17 and Treg percentages from cell cultures were measured by flow cytometry. Vitamin A levels in the SLE patients were lower compared to those in the healthy control (46.9 ± 43.4 vs. 75.6 ± 73.1 ng/ml, p = 0.015). Vitamin A levels also had a negative correlation to Th17 percentages in the SLE patients (p = 0.000, R = -0.642). Th17 percentages in the hypovitaminosis A SLE patients were higher compared to those SLE patients with normal vitamin A levels (10.9 ± 5.3 vs. 2.9 ± 2.2 %, p = 0.000). Treatment of 0.3 μg/ml of retinoic acid could increase Treg differentiation (33.9 ± 1.6 vs. 21.8 ± 1.1 %, p = 0.000) and decrease Th17 differentiation (27.2 ± 2.5 vs. 37.4 ± 1.3 %, p = 0.000). In conclusion, vitamin A has important roles in modulating Th17/Treg balance in the SLE patients shown by the significant decrease of vitamin A levels in the SLE patients which negatively correlate with Th17 population, and treatment of retinoic acid could decrease Th17 and increase Treg percentages in CD4(+) T cells cultures.