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Summary: Humanized non‐obese diabetic/severe combined immunodeficiency/interleukin‐2 receptor‐γ‐null (NOD/SCID/IL2rγnull) [humanized (huNSG)] mice engrafted with human hematopoietic cells have been used for investigations of the human immune system. However, the epigenetic features of the human regulatory T (Treg) cells of huNSG mice have not been studied. The objective of this study was to clarify the characteristics of human Treg cells in huNSG mice, especially in terms of the epigenetic aspects. We compared the populations, inhibitory molecule expression and suppressive capacity of human Treg cells in spleens harvested from the huNSG mice 120 days after the engraftment of human umbilical cord blood CD34+ cells with human peripheral blood mononuclear cells (PBMCs). Histone modifications and enhancer of zeste homolog 2 (Ezh2), an H3K27 methyltransferase, of human Treg cells were quantified in huNSG mice and human PBMCs. The effect of Ezh2 inhibitor on human Treg cells exposed to interleukin (IL)‐6 was also compared between them. Human Treg cells in the spleens of huNSG mice showed an increased proportion among CD4+ T cells, higher expressions of forkhead box protein 3 (FoxP3), cytotoxic T lymphocyte antigen 4 (CTLA‐4) and glucocorticoid‐induced tumor necrosis factor‐related protein (GITR), a higher production of IL‐10 and enhanced suppressive capacity when compared with those in human PBMCs. H3K27me3 and Ezh2 were specifically up‐regulated in human Treg cells of huNSG mice in comparison with those of human PBMCs. The decrease in Treg cells induced by IL‐6 exposure was attenuated in huNSG mice when compared with human PBMCs, while the difference between them was cancelled by addition of Ezh2 inhibitor. In conclusion, huNSG mice exhibit functionally augmented human Treg cells owing to enzymatic up‐regulation of H3K27me3. [ABSTRACT FROM AUTHOR]

Contemporary mushroom factories are places where there is a substantial risk of the occurrence of respiratory allergy. The aims of this investigation were to estimate its causative agents and to evaluate the contribution of innate immune response in mushroom workers who cultivate Hypsizigus marmoreus (Bunashimeji). Cross-sectional and follow-up studies were performed in the factory. We investigated CD1b, CD3, CD4, CD8, CD14, CD45RO, CD62L and CD161 expression in peripheral blood mononuclear cells (PBMC) by flow cytometry, and serum levels of interleukin (IL-2), IL-4, granulocyte-macrophage colony stimulating factor (GM-CSF), IL-13 and interferon (IFN)- γ by enzyme-linked immunosorbent assay (ELISA). Co-culture experiments of PBMC with spore extracts were also performed. Percentages of CD1b+ monocytes, natural killer (NK), NK T and CD4+ T cells were increased in the workers compared with controls. Increases in Th2 type cells, Th2/Th1 ratio and serum IL-13 and decreased IFN- γ were detected, indicating a Th2-biased status of the workers. The follow-up study showed that monocytes and NK cells increased soon after employment while CD4+ T, Th2 and NK T cells increased gradually as employment time lengthened. Serum precipitating antibody to the mushroom antigen could be detected at a later stage. Co-cultivation of PBMC with the spore extracts induced much higher CD1b expression, and suppressed secretion of Th1 cytokine in culture supernatants. These results indicate that the mushroom antigen contains highly immunogenic substances which stimulate PBMC into a Th2-biased in vivo status, and innate immune cells might also play a critical role in developing respiratory allergy in mushroom workers. [ABSTRACT FROM AUTHOR]

SUMMARY In sarcoidosis, a T helper 1 (Th1) response is an essential event and the up-regulation of interleukin-12 (IL-12) has been detected in affected disease sites. In order to investigate the clinical usefulness of circulating IL-12, we measured the serum concentrations of IL-12 by ELISA and performed immunohistochemistry using specific MoAbs for IL-12 in the lungs and scalene lymph nodes of patients with sarcoidosis. The serum concentration of IL-12 p40 was detectable in all 45 patients with pulmonary sarcoidosis and 18 normal controls, whereas that of IL-12 p70 was undetectable. The serum concentrations of IL-12 p40 in pulmonary sarcoidosis were significantly higher than those of the normal controls, especially in cases with abnormal intrathoracic findings detected by chest roentogenogram. The serum concentrations of interferon-γ (IFN-γ ) also increased compared with those of normal controls and there was a significant positive correlation between the serum concentrations of IL-12 p40 and IFN-γ . Furthermore, serum angiotensin-converting enzyme (ACE) and lysozyme, which are known to be useful markers for disease activity in sarcoidosis, correlated well with the serum concentrations of IL-12 p40. The positive 67 Ga scan group (for lung field) had significantly elevated serum IL-12 p40 levels compared with those of the negative group. No bioactivity of IL-12 p70 was detected in three sarcoid cases sera by using the IL-12 responsive cell line. Finally, the immunohistochemical approach revealed that IL-12 p40 was expressed in the epithelioid cells and macrophages of sarcoid lungs and lymph nodes. We concluded that the production of IL-12 p40 was far greater in the sera and we have demonstrated this to be a useful clinical marker for disease activity and the Th1 response in pulmonary sarcoidosis. [ABSTRACT FROM AUTHOR]

Epidemiological and experimental studies suggest that diesel exhaust particles (DEP) may play an active role in the increased respiratory mortality and morbidity. We have shown that DEP augmented the production of inflammatory cytokines by human airway epithelial cells in vitro. ICAM-1 has been shown to play an important role in the local accumulation of inflammatory cells. We studied the effect of DEP on ICAM-1 gene expression and surface expression in human bronchial epithelial cell line BEAS-2B. DEP (5–50 μg/ml) showed a stimulatory effect on ICAM-1 mRNA levels as evaluated by reverse transcription-polymerase chain reaction (RT-PCR). Flow cytometric analysis demonstrated an increased ICAM-1 expression on the epithelial cell surfaces. The soluble form of ICAM-1 molecules was also increased by the stimulation of DEP. In vitro neutrophil attachment onto DEP-stimulated epithelial cells was augmented, which was partially blocked by anti-ICAM-1 neutralizing antibody. Finally, these events were significantly inhibited by pretreatment with anti-oxidants pyrrolidine dithiocarbamate and N-acetyl cysteine, and p38 mitogen activated protein kinase (MAPK) inhibitor SB203580. These findings suggested that DEP induced up-regulation of ICAM-1 gene, and this process might be largely dependent on oxidant-mediated NF-κB activation and p38-MAPK pathways. [ABSTRACT FROM AUTHOR]

ICAM-l plays an important role in inflammatory diseases. We analysed ICAM-l expression on BAL fluid cells and measured soluble ICAM-l (sICAM-I) concentrations in sent and BAL fluids from patients with extrinsic allergic alveolitis (EAA). We found significantly increased cellular ICAM-1 expression on BAL fluid lymphocytes and alveolar marcrophages, and significantly increased values of circulating and BAL fluid sICAM-l in EAA patients compared with controls. Successive measurement shows prompt decrease of both sICAM-l values in EAA patients during periods when antigen exposure was prevented. In BAL fluids from EAA patients sICAM-l values significantly correlated to neutrophil and ICAM-1+ lymphocyte counts. In EAA patients, circulating and BAL fluid sICAM-1 values has significant negative correlations to values of carbon monoxide diffusing capacity and to time intervals between last episode and sample collection. However, these values had significant positive correlation to values of alveolar arterial oxygen pressure difference. In EAA, antigen exposure appears to induce cellular ICAM-l expression on BAL fluid cells, and also appears to up-regulate shedding of ICAM-l in the alveolar lining fluid and in the circulation. The sICAM values appear to reflect disease activity of EAA. [ABSTRACT FROM AUTHOR]

ICAM-I plays an important role in inflammatory diseases. To assess level of soluble ICAM-I in the circulation and inflamed lesions, we measured levels of soluble ICAM-1 in the circulation and bronchoalvcolar lavage fluid (BALF) of patients with idiopathic pulmonary fibrosis (IPF) and with pulmonary sarcoidosis (PS) and of healthy volunteers (HV), and we also analysed ICAM-I expression of BALF cells in some patients and HV. IPF patients had significantly higher levels of circulating ICAM-I than HV, while PS patients did not. By contrast, significantly increased levels of BALF soluble ICAM-I were found in PS patients compared with those of HV, but not in IPF patients. There were no significant differences in the proportions of ICAM-1+ BALF lymphocytes in IPF patients, PS patients and HV, whereas significantly increased proportions of ICAM-I + pulmonary alveolar macrophages were found in PS patients compared with those of HV, but not in IPF patients. There was a significant positive correlation of BALF soluble ICAM-I levels to BALF lymphocyte proportions in PS patients. Although the source of BALF soluble ICAM-l is unclear, BALF soluble ICAM-1 appears to reflect the grade of local activity of sarcoidosis. An interesting discrepancy between soluble ICAM-1 levels in the circulation and BALF was found in IPF patients, and this might be an important clue to an understanding of this disorder. [ABSTRACT FROM AUTHOR]