Effect of four hydroxy fatty acids on lipid accumulation in the 3T3-L1 cells: A comparative study.

Notwithstanding the several investigations of the hydroxy fatty acids (hFAs)' physiological functions, studies focusing on their anti-obesity effects are limited. This study investigated the anti-obesity effects of four hFAs, 10-hydroxy stearic acid (10-hSA), 12-hydroxy stearic acid (12-hSA), 9,12-hydroxy stearic acid (9,12-dhSA), and 12-hydroxy oleic acid (12-hOA), on the 3T3-L1 cells. All hFAs suppressed lipid accumulation, with 10-hSA and 12-hOA exhibiting the strongest suppression, followed by 12-hSA and 9, 12-hSA. This trend was similar to that observed for the glycerol-3-phosphate dehydrogenase (GPDH) activity degree. Contrastingly, only 9,12-dhSA suppressed cell viability. The mRNA levels of HK1 and Aldoa were markedly suppressed by 10-hSA and 12-hSA compared to the control. Additionally, mRNA expression of Gyk was considerably suppressed by 12-hSA. Thus, all hFAs suppressed lipid accumulation by suppressing GPDH activity, although their molecular mechanisms were different. These findings will aid the application of hFAs in the food and medical industries.

Effect of IL-15 addition on asbestos-induced suppression of human cytotoxic T lymphocyte induction.

BACKGROUND: Asbestos fibers possess tumorigenicity and are thought to cause mesothelioma. We have previously reported that exposure to asbestos fibers causes a reduction in antitumor immunity. Asbestos exposure in the mixed lymphocyte reaction (MLR) showed suppressed induction of cytotoxic T lymphocytes (CTLs), accompanied by a decrease in proliferation of CD8+ T cells. Recently, we reported that asbestos-induced suppression of CTL induction is not due to insufficient levels of interleukin-2 (IL-2). In this study, we continue to investigate the mechanism responsible for the effect of asbestos fibers on the differentiation of CTLs and focus on interleukin-15 (IL-15) which is known to be a regulator of T lymphocyte proliferation. METHODS: For MLR, human peripheral blood mononuclear cells (PBMCs) were cultured with irradiated allogenic PBMCs upon exposure to chrysotile B asbestos at 5 µg/ml for 7 days. After 2 days of culture, IL-15 was added at 1 ng/ml. After 7 days of MLR, PBMCs were collected and analyzed for phenotypic and functional markers of CD8+ T cells with fluorescence-labeled anti-CD3, anti-CD8, anti-CD45RA, anti-CD45RO, anti-CD25, and anti-granzyme B antibodies using flow cytometry. To examine the effect of IL-15 on the expression level of intracellular granzyme B in proliferating and non-proliferating CD8+ lymphocytes, PBMCs were stained using carboxyfluorescein diacetate succinimidyl ester (CFSE) and then washed and used for the MLR. RESULTS: IL-15 addition partially reversed the decrease in CD3+CD8+ cell numbers and facilitated complete recovery of granzyme B+ cell percentages. IL-15 completely reversed the asbestos-induced decrease in percentage of granzyme B+ cells in both non-proliferating CFSE-positive and proliferating CFSE-negative CD8+ cells. The asbestos-induced decrease in the percentage of CD25+ and CD45RO+ cells in CD8+ lymphocytes was not reversed by IL-15. CONCLUSION: These findings indicate that CTLs induced upon exposure to asbestos possess dysfunctional machinery that can be partly compensated by IL-15 supplementation, and that IL-15 is more effective in the recovery of proliferation and granzyme B levels from asbestos-induced suppression of CTL induction compared with IL-2.

Effect of asbestos exposure on differentiation and function of cytotoxic T lymphocytes.

Asbestos exposure is known to cause malignant mesothelioma, which is associated with poor prognosis. We focused on and examined the effect of asbestos exposure on the differentiation and function of cytotoxic T lymphocytes (CTLs). CTLs have the ability to specifically attack tumor cells after being differentiated from naïve CD8+ T cells following antigen stimulation. Exposure to chrysotile B asbestos suppressed the differentiation of CTLs during the mixed lymphocyte reaction (MLR) and was associated with a decrease in proliferation of CD8+ T cells. Additionally, in an effort to investigate the mechanism associated with suppressed CTL differentiation upon exposure to asbestos, we focused on IL-2, a cytokine involved in T cell proliferation. Our findings indicated that insufficient levels of IL-2 are not the main cause for the suppressed induction of CTLs by asbestos exposure, although they suggest potential improvement in the suppressed CTL function. Furthermore, the functional properties of peripheral blood CD8+ lymphocytes from asbestos-exposed individuals with pleural plaque (PP) and patients with malignant mesothelioma (MM) were examined. MM patients showed lower perforin levels in CD8+ lymphocytes following stimulation compared with PP-positive individuals. The production capacity of IFN-γ in the MM group tended to be lower compared with healthy volunteers or PP-positive individuals. In an effort to determine whether chronic and direct asbestos exposure affected the function of CD8+ T cells, cultured human CD8+ T cells were employed as an in vitro model and subjected to long-term exposure to chrysotile (CH) asbestos. This resulted in decreased levels of intracellular perforin and secreted IFN-γ. Those findings underlie the possibility that impaired CD8+ lymphocyte function is caused by asbestos exposure, which fail to suppress the development of MM. Our studies therefore reveal novel effects of asbestos exposure on CTLs, which might contribute towards the development and implementation of an effective strategy for the prevention and cure of malignant mesothelioma.

Enhanced expression of nicotinamide nucleotide transhydrogenase (NNT) and its role in a human T cell line continuously exposed to asbestos.

The effects of asbestos fibers on human immune cells have not been well documented. We have developed a continuously exposed cell line model using the human T-lymphotropic virus 1 (HTLV-1)-immortalized human T cell line MT-2. Sublines continuously exposed to chrysotile (CH) or crocidolite (CR) showed acquired resistance to asbestos-induced apoptosis following transient and high-dose re-exposure with fibers. These sublines in addition to other immune cells such as natural killer cells or cytotoxic T lymphocytes exposed to asbestos showed a reduction in anti-tumor immunity. In this study, the expression of genes and molecules related to antioxidative stress was examined. Furthermore, complexes related to oxidative phosphorylation were investigated since the production of reactive oxygen species (ROS) is important when considering the effects of asbestos in carcinogenesis and the mechanisms involved in resistance to asbestos-induced apoptosis. In sublines continuously exposed to CH or CR, the expression of thioredoxin decreased. Interestingly, nicotinamide nucleotide transhydrogenase (NNT) expression was markedly enhanced. Thus, knockdown of NNT was then performed. Although the knockdown clones did not show any changes in proliferation or occurrence of apoptosis, these clones showed recovery of ROS production with returning NADPH/NADP+ ratio that increased with decreased production of ROS in continuously exposed sublines. These results indicated that NNT is a key factor in preventing ROS-induced cytotoxicity in T cells continuously exposed to asbestos. Considering that these sublines showed a reduction in anti-tumor immunity, modification of NNT may contribute to recovery of the anti-tumor effects in asbestos-exposed T cells.

Decrease in Intracellular Perforin Levels and IFN-γ Production in Human CD8+ T Cell Line following Long-Term Exposure to Asbestos Fibers.

Although the tumorigenicity of asbestos, which is thought to cause mesothelioma, has been clarified, its effect on antitumor immunity requires further investigation. We previously reported a decrease in the percentage of perforin+ cells of stimulated CD8+ lymphocytes derived from patients with malignant mesothelioma. Therefore, we examined the effects of long-term exposure to asbestos on CD8+ T cell functions by comparing long-term cultures of the human CD8+ T cell line EBT-8 with and without exposure to chrysotile (CH) asbestos as an in vitro model. Exposure to CH asbestos at 5 µg/ml or 30 µg/ml did not result in a decrease in intracellular granzyme B in EBT-8 cells. In contrast, the percentage of perforin+ cells decreased at both doses of CH exposure. CH exposure at 30 µg/ml did not suppress degranulation following stimulation with antibodies to CD3. Secreted production of IFN-γ stimulated via CD3 decreased by CH exposure at 30 µg/ml, although the percentage of IFN-γ + cells induced by PMA/ionomycin did not decrease. These results indicate that long-term exposure to asbestos can potentially suppress perforin levels and the production of IFN-γ in human CD8+ T cells.

Royal Jelly Supplementation Improves Menopausal Symptoms Such as Backache, Low Back Pain, and Anxiety in Postmenopausal Japanese Women.

OBJECTIVES: This study aimed to evaluate the effect of Royal Jelly (RJ) at a dose of 800 mg/day on menopausal symptoms in healthy Japanese postmenopausal women with placebo-controlled design. MATERIAL AND METHODS: A total of 42 healthy Japanese postmenopausal women have been recruited for this study. The subjects were randomized to oral treatment with either 800 mg of protease-digested lyophilized powder of RJ (enzyme-treated RJ) or placebo (800 mg of dextrin) daily for 12 weeks. The level of menopausal symptoms has been evaluated every 4 weeks, using menopausal symptoms questionnaire of Japanese women. Independent t-test was used to evaluate statistical significance of the treatment effects between the two groups. RESULTS AND CONCLUSION: All of the 42 women have completed the trial. There were significant differences related to the anxiety score (P = 0.046) and backache and low back pain score (P = 0.040) between 800 mg/day enzyme-treated RJ and placebo-treated groups after 12 weeks of administration, and no significant differences were found between the two groups in 4 weeks after intervention. No side effects were observed in either group. This study demonstrates that enzyme-treated RJ supplementation with doses of 800 mg/day is effective in relieving menopausal symptoms such as anxiety, backache, and low back pain in Japanese postmenopausal women.

Aberrant expression of FoxP3 in a human T cell line possessing regulatory T cell­like function and exposed continuously to asbestos fibers.

Prompted by the known carcinogenic activity of asbestos, our investigations revealed that asbestos causes a reduction in antitumor immunity. One mechanism involves the enhancement of regulatory T (Treg) cell function and volume assayed using MT­2 original cells (Org), an HTLV­1 immortalized human T cell line which possesses Treg­like function. Continuous and relatively low­dose exposure of MT­2 to asbestos fibers yielded sublines resistant to asbestos­induced apoptosis and enhanced Treg function via cell­cell contact mechanisms and increased the production of soluble factors such as interleukin (IL)­10 and transforming growth factor (TGF)­ß. Additionally, cell cycle progression was accelerated in these sublines. Subsequently, the status of the Treg­specific transcription factor FoxP3 was examined. Unexpectedly, FoxP3 mRNA levels decreased in the sublines, although significant changes in protein expression were absent. Methylation analysis of CpG sites located in the promoter region of FoxP3 in original MT­2 cells and sublines showed almost complete methylation in Org and slight hypomethylation in the sublines. Although treatment with the demethylating agent 5­aza­deoxycytidine tended to upregulate FoxP3 expression, the methylation status did not match the mRNA expression and enhanced function. Additionally, the expression of other transcription factors related to Treg did not differ between Org and subline CB1. Collectively, aberrant expression and methylation patterns of FoxP3 were detected in human T cells continuously exposed to asbestos, although cell function was enhanced by asbestos exposure. Future analyses to identify factors responsible for Treg functional enhancements induced by asbestos, such as the investigation of surface molecules, are needed for the development of strategies to prevent the occurrence of asbestos­induced cancers.

Decrease in Serum Amyloid a Protein Levels Following Three-month Stays in Negatively Charged Particle-dominant Indoor Air Conditions.

OBJECTIVE: The changes in serum adipokines and cytokines related to oxidative stress were examined during 3 months 'Off to On' and 'On to Off' periods using negatively charged particle-dominant indoor air conditions (NCPDIAC). METHODS: Seven volunteers participated in the study, which included 'OFF to 3 months ON' periods (ON trials) for a total of 16 times, and 'ON to 3 months OFF' (OFF trials) periods for a total of 13 times. RESULTS: With the exception of one case, serum amyloid A (SAA) levels decreased significantly during the ON trials. CONCLUSION: Considering that SAA is an acute phase reactive protein such as C reactive protein (CRP), this observed decrease might indicate the prevention of cardiovascular and atherosclerotic changes, since an increase in high-sensitive CRP is associated with the subsequent detection of these events.

Search for biomarkers of asbestos exposure and asbestos-induced cancers in investigations of the immunological effects of asbestos.

The immunological effects of asbestos exposure on various lymphocytes such as the regulatory T cell (Treg), responder CD4+ T helper cell (Tresp), CD8+ cytotoxic T lymphocytes (CTL), and natural killer (NK) cells were investigated. Results show that asbestos exposure impairs antitumor immunity through enhancement of regulatory T cell function and volume, reduction of CXCR3 chemokine receptor in responder CD4+ T helper cells, and impairment of the killing activities of CD8+ cytotoxic T lymphocytes (CTL) and NK cells. These findings were used to explore biological markers associated with asbestos exposure and asbestos-induced cancers and suggested the usefulness of serum/plasma IL-10 and TGF-ß, surface CXCR3 expression in Tresp, the secreting potential of IFN-γ in Tresp, intracellular perforin level in CTL, and surface expression NKp46 in NK cells. Although other unexplored cytokines in serum/plasma and molecules in these immunological cells, including Th17, should be investigated by experimental procedures in addition to a comprehensive analysis of screening methods, biomarkers based on immunological alterations may be helpful in clinical situations to screen the high-risk population exposed to asbestos and susceptible to asbestos-related cancers such as mesothelioma.

Clinical evaluation of CENP-B and Scl-70 autoantibodies in silicosis patients.

Silicosis patients (SIL) suffer from respiratory disorders and dysregulation of autoimmunity. Frequent complications such as rheumatoid arthritis, systemic sclerosis (SSc) and vasculitis are known in SIL. Furthermore, we reported previously that some SIL exhibited better respiratory conditions in association with a worse immunological status. In this study, the clinical roles of anti-CENP-B and Scl-70 autoantibodies in SIL were analyzed. The titer index (Log10) of anti-CENP-B autoantibody in SIL was higher than that of healthy volunteers (HV), and that of SSc was higher than those of HV and SIL. This titer index was positively correlated with an assumed immune status of 1 for HV, 2 for SIL, and 3 for SSc. Moreover, although factor analysis revealed that the titer index of the anti-CENP-B autoantibody formed the same factor with the anti-Scl-70 autoantibody, IgG value and age in SIL cases, another extracted factor indicated that the IgA value and anti-Scl-70 antibody were positively related, but anti-CENP-B showed an opposite pattern in the results of the factor analysis. These findings indicated that the titer index of anti-CENP-B autoantibody may be a biomarker for dysregulation in SIL cases. Future clinical follow-up of SIL may therefore require both respiratory and immunological assessment.

Induction of IL-17 production from human peripheral blood CD4+ cells by asbestos exposure.

We have previously reported that chronic, recurrent and low-dose exposure to asbestos fibers causes a reduction in antitumor immunity. Investigation of natural killer (NK) cells using an in vitro cell line model and comprising in vitro activation using freshly isolated NK cells co-cultured with chrysotile fibers, as well as NK cells derived from asbestos-exposed patients with pleural plaque (PP) or malignant mesothelioma (MM), revealed decreased expression of NK cell activating receptors such as NKG2D, 2B4 and NKp46. An in vitro differentiation and clonal expansion model for CD8+ cytotoxic T lymphocytes (CTLs) showed reduced cytotoxicity with decreased levels of cytotoxic molecules such as granzyme B and perforin, as well as suppressed proliferation of CTLs. Additionally, analysis of T helper cells showed that surface CXCR3, chemokine receptor, and the productive potential of interferon (IFN)γ were reduced following asbestos exposure in an in vitro cell line model and in peripheral CD4+ cells of asbestos-exposed patients. Moreover, experiments revealed that asbestos exposure enhanced regulatory T cell (Treg) function. This study also focused on CXCR3 expression and the Th-17 cell fraction. Following activation with T-cell receptor and co-culture with various concentrations of chrysotile fibers using freshly isolated CD4+ surface CXCR3 positive and negative fractions, the intracellular expression of CXCR3, IFNγ and IL-17 remained unchanged when co-cultured with chrysotile. However, subsequent re-stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin resulted in enhanced IL-17 production and expression, particularly in CD4+ surface CXCR3 positive cells. These results indicated that the balance and polarization between Treg and Th-17 fractions play an important role with respect to the immunological effects of asbestos and the associated reduction in antitumor immunity.

Accelerated cell cycle progression of human regulatory T cell-like cell line caused by continuous exposure to asbestos fibers.

Asbestos exposure causes malignant tumors such as lung cancer and malignant mesothelioma. Based on our hypothesis in which continuous exposure to asbestos of immune cells cause reduction of antitumor immunity, the decrease of natural killer cell killing activity with reduction of NKp46 activating receptor expression, inhibition of cytotoxic T cell clonal expansion, reduced CXCR3 chemokine receptor expression and production of interferon-γ production in CD4+ T cells were reported using cell line models, freshly isolated peripheral blood immune cells from health donors as well as asbestos exposed patients such as pleural plaque and mesothelioma. In addition to these findings, regulatory T cells (Treg) showed enhanced function through cell-cell contact and increased secretion of typical soluble factors, interleukin (IL)-10 and transforming growth factor (TGF)-ß, in a cell line model using the MT-2 human polyclonal T cells and its sublines exposed continuously to asbestos fibers. Since these sublines showed a remarkable reduction of FoxO1 transcription factor, which regulates various cell cycle regulators in asbestos-exposed sublines, the cell cycle progression in these sublines was examined and compared with that of the original MT-2 cells. Results showed that cyclin D1 expression was markedly enhanced, and various cyclin-dependent kinase-inhibitors were reduced with increased S phases in the sublines. Furthermore, the increase of cyclin D1 expression was regulated by FoxO1. The overall findings indicate that antitumor immunity in asbestos-exposed individuals may be reduced in Treg through changes in the function and volume of Treg.

The Suppressed Induction of Human Mature Cytotoxic T Lymphocytes Caused by Asbestos Is Not due to Interleukin-2 Insufficiency.

We previously reported that exposure to chrysotile B (CB) asbestos suppressed the induction of mature cytotoxic T lymphocytes (CTLs) during mixed lymphocyte reaction assays (MLRs) with a decrease in the proliferation of immature CTLs. However, the mechanism responsible for the effect of asbestos fibers on the differentiation of CTLs remains unclear. Since interleukin-2 (IL-2) is a regulator of T lymphocyte proliferation, we examined the effect of IL-2 addition on suppressed CTL differentiation in CB-exposed cultures using flow cytometry (FCM). When IL-2 was added at 1 ng/mL on the second day of MLRs, the asbestos-caused decreases in the proliferation and percentages of CD25+ and CD45RO+ cells in CD8+ lymphocytes were not recovered by IL-2 addition, although the decrease in percentage of granzyme B+ cells was partially recovered. CD8+ lymphocytes from the IL-2-treated culture with asbestos showed the same degree of cytotoxicity as those in cultures without IL-2 or asbestos. These findings indicate that IL-2 insufficiency is not the main cause for the suppressed induction of CTLs by asbestos exposure, although they suggest a potential for the improvement of such suppressed CTL functions. Secretory factors other than IL-2 in addition to membrane-bound stimulatory molecules may play a role in asbestos-caused suppressed CTL differentiation.

Biological Effects of Cloth Containing Specific Ore Powder in Patients with Pollen Allergy.

OBJECTIVE: The custom-homebuilding company, Cosmic Garden Co. Ltd., located in Okayama City, Japan was established in 1997 and uses specific natural ore powder (SNOP) in wall materials and surveys customers in order to improve allergic symptoms. METHODS: To investigate the biological effects of SNOP, patients with a pollen allergy were recruited to stay in a room surrounded by cloth containing SNOP (CCSNOP), and their symptoms and various biological parameters were compared with those of individuals staying in a room surrounded by control non-woven cloth (NWC). Each stay lasted 60 min. Before and immediately after the stay, a questionnaire regarding allergic symptoms, as well as POMS (Profile of Mood Status) and blood sampling, was performed. Post-stay minus pre-stay values were calculated and compared between CCSNOP and NWC groups. RESULTS: Results indicated that some symptoms, such as nasal obstruction and lacrimation, improved, and POMS evaluation showed that patients were calmer following a stay in CCSNOP. Relative eosinophils, non-specific Ig E, epidermal growth factor, monocyte chemotactic protein-1, and tumor necrosis factor-α increased following a stay in CCSNOP. CONCLUSION: This ore powder improved allergic symptoms, and long-term monitoring involving 1 to 2 months may be necessary to fully explore the biological and physical effects of SNOP on allergic patients.

FoxO1 regulates apoptosis induced by asbestos in the MT-2 human T-cell line.

Asbestos is known to cause malignant mesothelioma and lung cancer. Recent studies implicate tumor immunity in the development of various tumors, including malignant mesothelioma. In order to establish an in vitro T-cell model to clarify the effects of long-term exposure of asbestos on tumor immunity, in this study, human T-cell line MT-2 cells were cultured with asbestos for longer than 8 months and the resultant cells (MT-2Rst) were assessed for the expression of forkhead transcription factor FoxO1. Gene expression analysis revealed that the amount of FoxO1 mRNA decreased after long-term exposure of the MT-2 cells to asbestos. In accordance with this reduction in FoxO1, pro-apoptotic Foxo1 target genes Puma, Fas ligand and Bim were also seen to be down-regulated in MT-2Rst cells. Furthermore, shRNA-mediated knock-down of FoxO1 reduced the number of apoptotic parental MT-2 cells after treatment with asbestos. On the other hand, over-expression of FoxO1 did not affect asbestos-induced apoptosis in MT-2Rst cells. These results suggested that FoxO1 played an important role in regulating asbestos-induced apoptosis and confirmed the presence of multiple pathways regulating resistance to asbestos in MT-2Rst cells.

The proliferative effects of asbestos-exposed peripheral blood mononuclear cells on mesothelial cells.

Malignant mesothelioma (MM) is thought to arise from the direct effect of asbestos on mesothelial cells. However, MM takes a long time to develop following exposure to asbestos, which suggests that the effects of asbestos are complex. The present study examined the effects of asbestos exposure on the cell growth of MeT-5A human mesothelial cells via cytokines produced by immune cells. Peripheral blood mononuclear cells (PBMCs) were stimulated with antibodies against cluster of differentiation (CD)3 and CD28 upon exposure to the asbestos chrysotile A (CA) or crocidolite (CR); the growth of MeT-5A cells in media supplemented with PBMC culture supernatants was subsequently examined. MeT-5A cells exhibited an increase in proliferation when grown in supernatant from the 7-day PBMC culture exposed to CA or CR. Analysis of cytokine production demonstrated increased levels of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1α, IL-1ß, IL-3, IL-5, IL-13 and IL-17A in supernatants. Individual administration of these cytokines, excluding G-CSF and GM-CSF, led to an increase in cell growth of MeT-5A, whereas this effect was not observed following the combined administration of these cytokines. The results indicate that cytokines secreted by immune cells upon exposure to asbestos cause an increase in the growth activity of mesothelial cells, suggesting that alterations in the production of cytokines by immune cells may contribute to tumorigenesis in individuals exposed to asbestos.

Environmental factors and human health: fibrous and particulate substance-induced immunological disorders and construction of a health-promoting living environment.

Among the various scientific fields covered in the area of hygiene such as environmental medicine, epidemiology, public health and preventive medicine, we are investigating the immunological effects of fibrous and particulate substances in the environment and work surroundings, such as asbestos fibers and silica particles. In addition to these studies, we have attempted to construct health-promoting living conditions. Thus, in this review we will summarize our investigations regarding the (1) immunological effects of asbestos fibers, (2) immunological effects of silica particles, and (3) construction of a health-promoting living environment. This review article summarizes the 2014 Japanese Society for Hygiene (JSH) Award Lecture of the 85th Annual Meeting of the JSH entitled "Environmental health effects: immunological effects of fibrous and particulate matter and establishment of health-promoting environments" presented by the first author of this manuscript, Prof. Otsuki, Department of Hygiene, Kawasaki Medical School, Kurashiki, Japan, the recipient of the 2014 JSH award. The results of our experiments can be summarized as follows: (1) asbestos fibers reduce anti-tumor immunity, (2) silica particles chronically activate responder and regulatory T cells causing an unbalance of these two populations of T helper cells, which may contribute to the development of autoimmune disorders frequently complicating silicosis, and (3) living conditions to enhance natural killer cell activity were developed, which may promote the prevention of cancers and diminish symptoms of virus infections.

Enhancement of regulatory T cell-like suppressive function in MT-2 by long-term and low-dose exposure to asbestos.

Asbestos exposure causes lung fibrosis and various malignant tumors such as lung cancer and malignant mesothelioma. The effects of asbestos on immune cells have not been thoroughly investigated, although our previous reports showed that asbestos exposure reduced anti-tumor immunity. The effects of continuous exposure of regulatory T cells (Treg) to asbestos were examined using the HTLV-1 immortalized human T cell line MT-2, which possesses a suppressive function and expresses the Treg marker protein, Foxp3. Sublines were generated by the continuous exposure to low doses of asbestos fibers for more than one year. The sublines exposed to asbestos showed enhanced suppressive Treg function via cell-cell contact, and increased production of soluble factors such as IL-10 and transforming growth factor (TGF)-ß1. These results also indicated that asbestos exposure induced the reduction of anti-tumor immunity, and efforts to develop substances to reverse this reduction may be helpful in preventing the occurrence of asbestos-induced tumors.

Enhancement of NK Cell Cytotoxicity Induced by Long-Term Living in Negatively Charged-Particle Dominant Indoor Air-Conditions.

Investigation of house conditions that promote health revealed that negatively charged-particle dominant indoor air-conditions (NCPDIAC) induced immune stimulation. Negatively charged air-conditions were established using a fine charcoal powder on walls and ceilings and utilizing forced negatively charged particles (approximate diameter: 20 nm) dominant in indoor air-conditions created by applying an electric voltage (72 V) between the backside of the walls and the ground. We reported previously that these conditions induced a slight and significant increase of interleukin-2 during a 2.5-h stay and an increase of NK cell cytotoxicity when examining human subjects after a two-week night stay under these conditions. In the present study, seven healthy volunteers had a device installed to create NCPDIAC in the living or sleeping rooms of their own homes. Every three months the volunteers then turned the NCPDIAC device on or off. A total of 16 ON and 13 OFF trials were conducted and their biological effects were analyzed. NK activity increased during ON trials and decreased during OFF trials, although no other adverse effects were found. In addition, there were slight increases of epidermal growth factor (EGF) during ON trials. Furthermore, a comparison of the cytokine status between ON and OFF trials showed that basic immune status was stimulated slightly during ON trials under NCPIADC. Our overall findings indicate that the NCPDIAC device caused activation of NK activity and stimulated immune status, particularly only on NK activity, and therefore could be set in the home or office buildings.

Exposure to negatively charged-particle dominant air-conditions on human lymphocytes in vitro activates immunological responses.

Indoor air-conditions may play an important role in human health. Investigation of house conditions that promote health revealed that negatively charged-particle dominant indoor air-conditions (NAC) induced immune stimulation. NAC was established using fine charcoal powder on walls and ceilings and utilizing forced negatively charged particles (approximate diameter: 20 nm) dominant in indoor air-conditions created by applying an electric voltage (72 V) between the backside of the walls and the ground. We reported previously that these conditions induced a slight and significant increase of interleukin-2 during 2.5 h stay, and an increase of natural killer (NK) cell cytotoxicity, when examining human subjects after a two-week night stay under these conditions. In the present study, we investigated whether exposure to NAC in vitro affects immune conditions. Although the concentrations of particles were different, an incubator for cell culture with NAC was set and cellular compositions and functions of various freshly isolated human lymphocytes derived from healthy donors were assayed in the NAC incubator and compared with those of cultures in a standard (STD) incubator. Results showed that NAC cultivation caused an increase of CD25 and PD-1 expressing cells in the CD4 positive fraction, enhancement of NK cell cytotoxicity, production of interferon-y (IFNγ), and slight enhancement of regulatory T cell function. In addition, the formula designated as the "immune-index" clearly differed between STD and NAC culture conditions. Thus, NAC conditions may promote human health through slight activation of the immune system against cancer cells and virus infection as shown by this in vitro study and our previously reported human studies.