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For stringent regulations of exhaust gases from gasoline-powered vehicles, small amount of platinum-group metals (PGMs) in automotive catalysts is highly required. To satisfy this requirement, applications of base-metal catalysts such as Fe and Mn have been vigorously discussed and investigated. Previously, we reported that rare earth metals containing hexagonal Fe and Mn oxides work as effective support materials and active species in CO oxidation, C3H6 oxidation, and NO reduction. However, most of the base-metal oxides could be readily decomposed by gasoline engine aging at approximately 1000 °C. In this study, we show that hexagonal YbMnO3 (h-YbMnO3) can be obtained as single-phase using the simple coprecipitation method with H2O2. Moreover, h-YbMnO3 can function as a oxygen storage material, which maintains its hexagonal structure after hydrothermal aging at 1000 °C for 25 h owing to the small ionic radius of Yb. On the other hand, isostructural YMnO3 (h-YMnO3) can be easily decomposed under the same aging condition. The catalytic performances of Pd loaded materials (Pd/h-YbMnO3, Pd/Al2O3, and Pd/CeO2-ZrO2 (CZ)) on cordierite honeycomb substrates were evaluated. Among them, Pd/h-YbMnO3 exhibited the highest oxidation activities even though it had significantly lower specific surface area (SSA). In particular, Pd/h-YbMnO3 exhibits a strong effect on paraffin oxidation such as C3H8, which is less reactive than other olefinic and aromatic hydrocarbons for automotive catalysts. [ABSTRACT FROM AUTHOR]

Regulatory T cells (Tregs) play pivotal role in cancer-induced immunoediting. Increment of CD25high+FOXP3+ natural Tregs has been reported in patients with hepatocellular carcinoma (HCC); however, the involvement of other type of Tregs remain elusive. We aimed to clarify whether FOXP3− Tregs are increased and functionally suppressive or not in patients with HCC. We enrolled 184 hepatitis C-infected patients with chronic liver diseases or HCC, 57 healthy subjects and 27 HCC patients with other etiology. Distinct Treg subsets were phenotypically identified by the expression of CD4, CD25, CD127 and forkhead/winged helix transcription factor (FOXP3). Their gene profiles, frequency and suppressor functions against T cell proliferation were compared among the subjects. To examine the molecules involving in Treg differentiation, we cultured naive CD4+ T cells in the presence of HCC cells and dendritic cells. We determined two types of CD4+CD127− T cells with comparable regulatory ability; one is CD25high+ cells expressing FOXP3 (CD25high+FOXP3+ Tregs) and the other is CD25− cells without FOXP3− expression (CD25−FOXP3− cells). The peripheral or intrahepatic frequency of CD25−FOXP3− Tregs in HCC patients is higher than those in other groups, of which significance is more than CD25high+FOXP3+ cells. Of importance, CD25−FOXP3− Tregs, but not CD25high+FOXP3+ cells, dynamically change in patients accompanied by the ablation or the recurrence of HCC. CD25−FOXP3− T cells with CD127−IL-10+ phenotype are inducible in vitro from naive CD4+ T cells, in which programmed cell death 1 ligand 1, immunoglobulin-like transcript 4 and human leukocyte antigen G are involved.. In conclusion, CD25−FOXP3− Tregs with suppressive capacity are increased in patients with HCC, suggesting their distinct roles from CD25+FOXP3+ Tregs. [ABSTRACT FROM AUTHOR]

Abstract: Background: Dendritic cells (DCs) utilize Toll-like receptors (TLRs) to sense virus and initiate immune responses. We aimed at elucidating the roles of TLRs on DCs in hepatitis C virus (HCV) infection. Methods: Monocyte-derived DCs were obtained from 32 healthy volunteers (HV) and 30 chronically HCV-infected patients (CH). TLR2, TLR3 and TLR4 expressions on immature DCs were quantified by real-time quantitative RT-PCR. We stimulated DCs with specific TLR ligands and examined DC maturation, cytokine production and ability to stimulate allogeneic CD4+ T cells. Results: TLR2 expression on immature DCs was lower in the CH group, whereas those of TLR3 or TLR4 were not different between the groups. Each TLR ligand induced DC maturation and stimulated them to release comparable levels of IL-12p70, IL-6, IL-10, TNF-α and IFN-β between the groups. TLR2 and TLR4 ligands enhanced DC ability to stimulate T cell proliferation, with the degree due to the TLR2 ligand being lower in the CH group. Conclusions: In HCV infection, the TLR2 expression on DCs is reduced and TLR2-stimulated DCs show lesser ability to proliferate T cells than healthy counterparts, suggesting that the TLR2 system is involved in HCV-induced immunopathogenesis. [Copyright &y& Elsevier]

Hepatitis C virus (HCV) induces chronic liver disease in hosts which can eventually progresses to liver cirrhosis and hepatocellular carcinoma. However, progression of liver disease is slower in patients with persistently normal levels of alanine aminotransferase (ALT) than in those with active hepatitis. Although distinct immune responses against HCV have been proposed in asymptomatic infection, the role of circulating dendritic cells (DC) in the pathogenesis of these patients remains obscure. To address this issue, we compared the number and function of myeloid DC (MDC) and plasmacytoid DC (PDC) between uninfected individuals and HCV-infected patients with or without elevated ALT levels. Numbers of DC and DC progenitors were significantly lower in patients with chronic active hepatitis than in control subjects. However, no differences were found in the number of DC between normal controls and HCV-infected patients with persistently normal ALT levels. MDC from patients with active hepatitis were less able to polarize naive CD4 T cells into the Th1 phenotype, while their MDC and PDC primed more CD4 T cells producing IL-10 than those from normal controls. Such dysfunction of DC was also observed in patients with persistently normal ALT levels. In conclusion, circulating DC decrease in number predominantly in HCV-infected patients with active hepatitis, and the function of DC is impaired even in those with normal ALT levels. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Laboratory strains of Chlamydomonas reinhardtii, which are descendants of a 1945 isolate by G.M. Smith (Harris 1989), were divided into two groups depending upon whether the vegetative cells require light to differentiate into gametes under ammonium ion-starved conditions. Light-dependent (LD) strains were unable to become gametes in the dark, while light-independent (LI) strains could do so. All the wild-type strains isolated recently from the field showed light-dependency, suggesting that the LD-phenotype is the wild-type. The LD-cells failed to acquire flagellar agglutinability, to accumulate cell body agglutinins, or to form mating structures in the dark, but did so rapidly after transfer to light. Moreover, the light-induced LD-gametes, but not the Li-gametes, lost their mating ability, cell body agglutinins, and mating structures after transfer to darkness, indicating that the LD-cells require light not only for gametic differentiation but also for maintenance of gametic activity. [ABSTRACT FROM AUTHOR]

Regulatory T cells (Tregs) play pivotal role in cancer-induced immunoediting. Increment of CD25(high+) FOXP3+ natural Tregs has been reported in patients with hepatocellular carcinoma (HCC); however, the involvement of other type of Tregs remain elusive. We aimed to clarify whether FOXP3- Tregs are increased and functionally suppressive or not in patients with HCC. We enrolled 184 hepatitis C-infected patients with chronic liver diseases or HCC, 57 healthy subjects and 27 HCC patients with other etiology. Distinct Treg subsets were phenotypically identified by the expression of CD4, CD25, CD127 and forkhead/winged helix transcription factor (FOXP3). Their gene profiles, frequency and suppressor functions against T cell proliferation were compared among the subjects. To examine the molecules involving in Treg differentiation, we cultured naive CD4+ T cells in the presence of HCC cells and dendritic cells. We determined two types of CD4+ CD127- T cells with comparable regulatory ability; one is CD25(high+) cells expressing FOXP3 (CD25(high+) FOXP3+ Tregs) and the other is CD25- cells without FOXP3- expression (CD25- FOXP3- cells). The peripheral or intrahepatic frequency of CD25- FOXP3- Tregs in HCC patients is higher than those in other groups, of which significance is more than CD25(high+) FOXP3+ cells. Of importance, CD25- FOXP3- Tregs, but not CD25(high+) FOXP3+ cells, dynamically change in patients accompanied by the ablation or the recurrence of HCC. CD25- FOXP3- T cells with CD127- IL-10+ phenoype are inducible in vitro from naive CD4(+) T cells, in which programmed cell death 1 ligand 1, immunoglobulin-like transcript 4 and human leukocyte antigen G are involved.. In conclusion, CD25- FOXP3- Tregs with suppressive capacity are increased in patients with HCC, suggesting their distinct roles from CD25+ FOXP3+ Tregs., (Copyright © 2012 UICC.)

Dendritic cells (DCs) are one of the promising tools for enhancing antigen-specific immune responses in clinical settings. Many studies have been performed thus far to verify the efficacy of the DC vaccine in cancer patients; however, the responses have not always been satisfactory, partly because of DC incompetence. To obtain DCs potentially applicable for vaccination of cancer patients, our group sought to establish the strategy of DC generation mainly by modulating culture periods and maturation stimuli. Novel mature DCs that can be generated from monocytes within 3 days by using a combination of OK432 (Streptococcus pyogenes preparation), low-dose prostaglandin E2 (PGE2), and interferon-alpha (OPA-DCs) were developed. They strongly express CD83, CD86, and CCR7 and have potent ability to migrate to CCL21. In addition, they were able to activate natural killer and T helper 1 (TH1) cells and to induce peptide-antigen-specific cytotoxic T lymphocytes more significantly than monocyte-derived DCs stimulated with a conventional cytokine cocktail of tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, and PGE2 (monocyte-conditioned medium [MCM]-mimic DCs). The profound ability of OPA-DCs to stimulate these effectors is attributable to their higher expression of IL-12p70, IL-23, and IL-27 than MCM-mimic DCs, which was supported by the findings that the neutralization of IL-12p70 and IL-23 reduced the TH1 priming ability of OPA-DCs. Even when from advanced gastric or colonic cancer patients, OPA-DCs displayed abilities of migration and TH1 induction comparable to those from healthy subjects. Therefore, OPA-DCs may serve as a feasible vaccine with the potential to enhance TH1-dominant and cytolytic immune responses against cancers.