Dimethyl 2,2-dichlorovinyl phosphate (DDVP) markedly decreases the expression of perforin, granzyme A and granulysin in human NK-92CI cell line

Induction Therapies Determine the Distribution of Perforin and Granzyme B Transcripts in Kidney Transplant Recipients

Peripheral blood mononuclear cells contain secretory granules with Perforin and Granzyme B for defense against pathogens. The objective of the present study was to compare the effects of immunosuppressive induction therapies on Perforin and Granzyme B transcripts in kidney transplant recipients. Transcripts were determined in 408 incident kidney transplant recipients eight days posttransplant using quantitative real-time PCR. Compared to 90 healthy subjects, the median Perforin transcripts were lower in kidney transplant recipients with blood-group ABO-incompatible donors (N = 52), compatible living donors (N = 130), and deceased donors (N = 226) (25.7%; IQR, 6.5% to 46.0%; 31.5%; IQR, 10.9% to 57.7%; and 35.6%; IQR, 20.6% to 60.2%; respectively; p = 0.015 by the Kruskal-Wallis test). Kidney transplant recipients who were treated with thymoglobulin (N = 64) had significantly lower Perforin as well as Granzyme B compared to all other induction therapies (N = 344) (each p < 0.001). Receiver operator characteristics analysis showed that both Perforin (area under curve, 0.919) and Granzyme B (area under curve, 0.915) indicated thyroglobulin-containing induction therapies. Regression analysis showed that both reduction in plasma creatinine and human leukocyte antigen mismatches were positively associated with elevated Perforin/Granzyme B transcript ratio posttransplant. We conclude clinical parameters and therapies affect Perforin and Granzyme B transcripts posttransplant.

Dietary chlorpyrifos-methyl exposure impair transcription of immune-, detoxification- and redox signaling genes in leukocytes isolated from cod (Gadus morhua)

Inclusion of new environmental toxicants increase with the amount of plant ingredients substituting marine proteins and oils in feed for farmed Atlantic salmon (Salma salar). Agricultural pesticides like chlorpyrifos-methyl, present in commercial salmon feeds, may affect salmon immune and detoxification responses. Atlantic cod (Gadus morhua), surrounding the net pens, grazing on feces and uneaten pellets may be affected accordingly. The aim of this study was to analyze transcription responses in Atlantic cod head kidney tissue and isolated leukocytes following dietary chlorpyrifos-methyl inclusions and possible interactions with proinflammatory signals. Head kidney tissues and leukocytes were isolated from cod fed diets contaminated with chlorpyrifos-methyl (0.5 mg/kg, 2.4 mg/kg, 23.2 mg/kg) for 30 days. The isolated leukocytes were further challenged with bacteria (lipopolysaccharide (LPS), virus (polyinosinic acid:polycytidylic acid (PIC) mimic and l-arginine, an immuno-modulating amino acid, in vitro. The LPS-induced transcription of the interleukin genes il-1β, il-6, il-8 increased in leukocytes isolated from cod fed chlorpyrifos-methyl 23.2 mg/kg, compared to cod fed the control diet, indicating increased inflammation. Transcriptional levels of carnitine palmitoyl transferase (cpt1a), aryl hydrogen receptor (ahr) and catalase (cat) were all reduced by dietary inclusions of chlorpyrifos-methyl in the leukocytes. The findings suggests that dietary chlorpyrifos-methyl exposure impair inflammation, detoxification and redox signaling in cod leukocytes.

The Effects of Forest Therapy on Immune Function

We conducted a systematic review of the effects of a forest therapy program on adults’ immune function. We used PICO-SD (participants, interventions, comparisons, outcomes, study design) to identify key items. The participants were adults over the age of 18 and the intervention was forest therapy. Our comparisons included studies that comparatively analyzed urban groups or groups that did not participate in forest therapy intervention. Cases without control groups were also included. Immunological outcome measures were included in measuring intervention outcomes. All experimental studies, such as randomized controlled trials (RCTs), non-equivalent control group designs (non-RCTs), and one-group pretest-posttest design were included in the study design. A total of 13 studies were included for comparison. Forest therapy programs were divided into lodging-type and session-type programs. The representative measures for evaluating the effects of immune function were the number of NK cells, the cytotoxic activity of NK cells, and cytotoxic effector molecules. Most studies reported improvement in these measures when comparing values after intervention with values before the forest therapy intervention. Therefore, forest therapy has been found to be effective in improving immune function. More RCT studies on the effects of forest therapy on immune function are necessary.

Evaluation of triazophos induced immunotoxicity of spleen and head kidney in fresh water teleost, Channa punctata

The utilization of pesticides has increased for destroying pests and protecting crops in the agriculture field. Triazophos is a commonly used organophosphorous insecticide that causes alterations in haematological and histological parameters in fish. The present study was designed to evaluate the effect of triazophos induced innate and cell mediated immunotoxicity in freshwater teleost, Channa punctata. Fishes were exposed to triazophos at concentrations 5 and 10% of LC₅₀ value for 10 and 20 days. Splenic and head kidney macrophage phagocytosis, nitric oxide production and superoxide production were assayed to evaluate the innate immunity. Cell-mediated immunity was measured through splenic and head kidney lymphocyte proliferation in presence of T and B cell mitogens. Results of the present study revealed that macrophage phagocytosis was significantly reduced after in vivo triazophos treatment. Differential suppressive effect of triazophos was also observed where mitogen induced splenic and head kidney lymphocyte proliferations were reduced after 10 and 20 days treatment. Concentration dependent effect of triazophos was observed in in vivo studies where the production of reactive oxygen and nitrogen intermediates were suppressed. This study describes the first investigation of the effect of triazophos on immune functions and will help to determine appropriate ecotoxicity and immunotoxicity in freshwater teleosts.

Analysis of suppressive effects of pesticide triazophos on leucocyte immune responses in a teleost, Channa Punctatus

Triazophos is a commonly used organophosphate insecticide, which inhibits the acetylcholinesterase enzyme and causes paralysis and death of insects. Impact of the pesticides on immunity has scarcely been investigated, especially in fishes. The present study was designed to analyze the immunotoxic role of in vitro triazophos exposure to the leucocytes in freshwater teleost, Channa punctatus. Triazophos, at in vitro concentrations of 0.1, 0.5, and 1 µg ml^-1, was used to study leucocyte phagocytosis, superoxide production, nitrite release, and lymphocyte proliferation. Dose-dependent suppression of various immune responses was observed. Nitrite release and superoxide production by leucocytes were reduced in cultures incubated with triazophos. Mitogen-induced lymphocyte proliferation was significantly reduced at 0.5 and 1 µg ml^-1 but not at 0.1 µg ml^-1 concentration of pesticide. The biphasic suppressive effect was also discovered while evaluating phagocytic response. These investigations describe the effects of pesticide on immune responses in C. punctatus, which are helpful in understanding the immunotoxicity in fish. Substantially more researches are required to help design the measures to combat ecotoxicity in freshwater bodies.

The Potential Benefits of Therapeutic Treatment Using Gaseous Terpenes at Ambient Low Levels

Biological volatile organic compounds (BVOCs) are emitted abundantly from the flora. Among BVOCs, monoterpenes (MTs) have been used for aromatherapy (e.g., forest bathing) to treat human physiological and psychological conditions. However, relatively little is known about the therapeutic effects of MTs at low part per billion by volume (ppbv) levels. The effects of artificial MTs on human subjects were assessed by both olfactory and therapeutic parameters (brain alpha waves and stress index). Gaseous standards of three monoterpenes (i.e., α-pinene, β-pinene, and d-limonene) prepared at low ppbv levels were used individually and as mixtures. Fifty-nine healthy and non-asthmatics volunteer university students were selected for the test. All human subjects inhaled low ppbv levels of monoterpene in the testing room. Brain alpha waves and stress index were investigated during the inhalation time. Questionnaires were also used after testing. It was found that the detection threshold of MTs was close to 5 ppbv. When the MT levels increased from 0 to 20 ppbv, the mean values of brain alpha waves derived from all participants increased from 9.8 to 15.1. In contrast, the stress index values declined from 46.2 to 34.7. The overall results suggest that MTs have great potential to positively affect the relaxation state of subjects in a manner similar to forest bathing in terms of short-term effect. They can thus be applied as potential therapeutic media for mental health care.

Natural Killer (NK) Cell Assays in Immunotoxicity Testing

It is well known that natural killer (NK) cells are involved in defense against viruses and some tumors. NK cells kill target cells by the directed release of cytolytic granules that contain perforin, granzymes, and granulysin. It is increasingly important to evaluate NK cell function in immunotoxicity testing. NK cell function can be evaluated by determining cytolytic activity against target tumor cells by the ⁵¹Cr-release assay and also by determining the number of NK cells in peripheral blood in humans and in the spleen in animals using flow cytometry. Recently, the intracellular levels of perforin, granzymes, and granulysin determined by flow cytometry have also been used in the evaluation of NK cell function. In addition, chemical-induced apoptosis in NK cells also has been applied to evaluate the immunotoxicity of chemicals. This chapter will describe the methods for NK cell assays in immunotoxicity testing.

Effect of carbamate pesticides on perforin, granzymes A-B-3/K, and granulysin in human natural killer cells

We previously found that ziram, a carbamate pesticide, significantly reduced perforin, granzyme A (GrA), granzyme B (GrB), granzyme 3/K (Gr3/K), and granulysin (GRN) levels in NK-92MI cells, a human natural killer (NK) cell line. To investigate whether other carbamate pesticides also show similar toxicity on human NK cells, we conducted further experiments with NK-92CI cells, a human NK cell line, using a more sensitive assay. We previously confirmed that NK-92CI cells express CD56, perforin, GrA, GrB, Gr3/K, and GRN and are highly cytotoxic to K562 cells in a chromium release assay, which are more sensitive to organophosphorus pesticides and ziram than the NK-92MI cell line. NK-92CI cells were treated with ziram, thiram, maneb, or carbaryl at various concentrations for 4–24 h at 37°C in vitro. Thereafter, intracellular levels of perforin, GrA, GrB, Gr3/K, and GRN were determined by flow cytometry. It was found that all carbamate pesticides significantly reduced the intracellular levels of perforin, GrA, GrB, Gr3/K, and GRN in NK-92CI cells in a dose-dependent manner. However, the strength of the effect differed among the pesticides, and the order was thiram > ziram > maneb > carbaryl. In addition, it was also found that the degree of the reductions differed among the five proteins, with perforin more sensitive to pesticides than GRN, GrA, GrB, and Gr3/K, and the order was perforin > GRN > Gr3/K ≒ GrA ≒ GrB.

Modulation of immune response by organophosphorus pesticides: fishes as a potential model in immunotoxicology

Immune response is modulated by different substances that are present in the environment. Nevertheless, some of these may cause an immunotoxic effect. In this paper, the effect of organophosphorus pesticides (frequent substances spilled in aquatic ecosystems) on the immune system of fishes and in immunotoxicology is reviewed. Furthermore, some cellular and molecular mechanisms that might be involved in immunoregulation mechanisms of organophosphorus pesticides are discussed.

Rhaphidophora korthalsii modulates peripheral blood natural killer cell proliferation, cytokine secretion and cytotoxicity

Background

Rhaphidophora korthalsii (Araceae) is a root-climber plant which has been widely used in Chinese traditional medicine for cancer and skin disease treatment. Previous reports have recorded its immunomodulatory effects on mice splenocyte and human peripheral blood. This study investigated the potential immunostimulatory effect of Rhaphidophora korthalsii on human PBMC enriched NK cell.

Methods

PBMC was exposed to various concentrations of R. korthalsii extract and the T and NK cell population in the control and extract treated PBMC were identified by immunophenotyping. Intracellular perforin and granzyme B expressions were detected by flow cytometry and extra-cellular Granzyme B, IFN-γ and TNF-α production in the isolated NK cells were determined by ELISA. The cytotoxicity of effector NK cell towards target K562 cell was assessed by CytoTox 96 assay.

Results

Rhaphidophora korthalsii methanol extract significantly increased PBMC NK cell population and intracellular perforin and granzyme B expressions. Moreover, the extract also enhanced the secretion of IFN-γ and TNF-α which subsequently enhanced the cytotoxicity of NK cell against the NK sensitive target K562 cell line. NK cell enriched with extract treated PBMC showed better activation than NK cell directly treated with the extract.

Conclusion

Our findings indicated a potential IL-2 free immunotherapy through direct and indirect R. korthalsii stimulation on NK cell activation.

Mechanism of ziram-induced apoptosis in human natural killer cells

We previously found that ziram, a dithiocarbamate fungicide, significantly inhibited natural killer (NK) activity in a dose-dependent manner. To explore the mechanism of this inhibition, we investigated ziram-induced apoptosis in human NK cells. Human NK-92MI cells were treated with ziram at 0.0625-4 &#181;M for 2-64 h. Apoptosis was determined by FITC-Annexin-V/PI staining. To explore the mechanism of apoptosis, intracellular levels of active caspases 3, 3/7, 8, and 9 and pan-caspase and mitochondrial cytochrome-c release were determined by flow cytometry. Disruption to mitochondrial transmembrane potential was determined with a MitoLight? Apoptosis Detection Kit. It was found that ziram induced apoptosis in a dose- and time-dependent manner in human NK cells. Ziram increased the intracellular levels of active caspases 3, 3/7, 8, and 9 and pan-caspase in a dose-dependent manner, and a caspase-3 inhibitor, Z-DEVD-FMK, and a general caspase inhibitor, Z-VAD-FMK, partially but significantly inhibited the apoptosis. Ziram also disrupted mitochondrial transmembrane potential and caused mitochondrial cytochrome-c release in a dose-dependent manner. These findings indicate that ziram can induce apoptosis in human NK cells, and the apoptosis is at least mediated by both the caspase-cascade and the mitochondria/cytochrome-c pathways.

Effect of forest bathing trips on human immune function

In Japan, a forest bathing trip, called "Shinrinyoku" in Japanese, is a short, leisurely visit to a forest; it is regarded as being similar to natural aromatherapy. This review focuses on the effects of forest bathing trips on human immune function. Beginning in 2005, adult Japanese individuals, both male and female, participated in a series of studies aimed at investigating the effect of forest bathing trips on human immune function. The subjects experienced a 3-day/2-night trip to forest areas, and blood and urine were sampled on days 2 (the first sampling during each trip) and 3 (the second sampling during each trip), and on days 7 and 30 after the trips. Natural killer (NK) activity, the numbers of NK, granulysin-, perforin-, and granzymes A/B-expressing lymphocytes in the blood, and the concentration of urinary adrenaline were measured. The same measurements were made before the trips on a normal working day as a control. The mean values of NK activity and the numbers of NK, granulysin-, perforin-, and granzymes A/B-expressing cells on forest bathing days were significantly higher than those on the control days, whereas the mean values of the concentration of urinary adrenaline on forest bathing days were significantly lower than that on the control days in both male and female subjects. The increased NK activity lasted for more than 30 days after the trip, suggesting that a forest bathing trip once a month would enable individuals to maintain a higher level of NK activity. In contrast, a visit to the city as a tourist did not increase NK activity, the numbers of NK cells, or the level of intracellular granulysin, perforin, and granzymes A/B. These findings indicate that forest bathing trips resulted in an increase in NK activity, which was mediated by increases in the number of NK cells and the levels of intracellular granulysin, perforin, and granzymes A/B.

Alpha-linolenic acid is a potent neuroprotective agent against soman-induced neuropathology

Nerve agents are deadly threats to military and civilian populations around the world. Nerve agents cause toxicity to peripheral and central sites through the irreversible inhibition of acetylcholinesterase, the enzyme that metabolizes acetylcholine. Excessive acetylcholine accumulation in synapses results in status epilepticus in the central nervous system. Prolonged status epilepticus leads to brain damage, neurological dysfunction and poor outcome. Anticonvulsants are effective but must be given rapidly following exposure. Because these agents cause mass casualties, effective neuroprotective agents are needed to reduce brain damage and improve cognitive outcome. α-Linolenic acid is an omega-3 fatty acid that is found in vegetable products and has no known side effects. α-Linolenic acid is neuroprotective against kainic acid-induced brain damage in vivo, but its neuroprotective efficacy against nerve agents is unknown. α-Linolenic acid also exerts anti-depressant and anti-inflammatory activities and enhances synaptic plasticity in vivo. These properties make this polyunsaturated fatty acid (PUFA) a potential candidate against nerve agent-induced neuropathology. Here we show that α-linolenic acid is neuroprotective against soman-induced neuropathology in either a pretreatment or post-treatment paradigm. We also show that subcutaneous injection of α-linolenic acid shows greater neuroprotective efficacy compared with intravenous injection in a brain region-specific manner.

A review of endosulfan, dichlorvos, diazinon, and diuron--pesticides used in Jamaica

The global agricultural sector is the primary user of pesticides, consuming more than three billion kilograms of pesticides annually. Although pesticides are beneficial in controlling the proliferation of pests, they have been associated with adverse human and ecological impacts. Approximately 87% of the annually imported pesticides in Jamaica are applied within agricultural or household settings. However, in Jamaica, the potential impact on humans, their property, and the environment is unknown, as the fate of many of the locally applied pesticides has not been established. This review discusses four pesticides extensively applied in agricultural practices in Jamaica - endosulfan, diazinon, diuron, and dichlorvos. The information presented is essential for the development of fate and transport models of these chemicals. Consequently, health and ecological impact assessments may be conducted from the generated models.

Effect of phytoncide from trees on human natural killer cell function

We previously reported that the forest environment enhanced human natural killer (NK) cell activity, the number of NK cells, and intracellular anti-cancer proteins in lymphocytes, and that the increased NK activity lasted for more than 7 days after trips to forests both in male and female subjects. To explore the factors in the forest environment that activated human NK cells, in the present study we investigate the effect of essential oils from trees on human immune function in twelve healthy male subjects, age 37-60 years, who stayed at an urban hotel for 3 nights from 7.00 p.m. to 8.00 a.m. Aromatic volatile substances (phytoncides) were produced by vaporizing Chamaecyparis obtusa (hinoki cypress) stem oil with a humidifier in the hotel room during the night stay. Blood samples were taken on the last day and urine samples were analysed every day during the stay. NK activity, the percentages of NK and T cells, and granulysin, perforin, granzyme A/B-expressing lymphocytes in blood, and the concentrations of adrenaline and noradrenaline in urine were measured. Similar control measurements were made before the stay on a normal working day. The concentrations of phytoncides in the hotel room air were measured. Phytoncide exposure significantly increased NK activity and the percentages of NK, perforin, granulysin, and granzyme A/B-expressing cells, and significantly decreased the percentage of T cells, and the concentrations of adrenaline and noradrenaline in urine. Phytoncides, such as alpha-pinene and beta-pinene, were detected in the hotel room air. These findings indicate that phytoncide exposure and decreased stress hormone levels may partially contribute to increased NK activity.

NK cell assays in immunotoxicity testing

It is well known that natural killer (NK) cells are involved in defense against viruses and some tumors. NK cells kill target cells by the directed release of cytolytic granules that contain perforin, granzymes, and granulysin. It is increasingly important to evaluate NK cell function in immunotoxicity testing. NK cell function can be evaluated by determining cytolytic activity against target tumor cells by the (51)Cr-release assay and also by determining the number of NK cells in peripheral blood in humans and in the spleen in animals using flow cytometry. Recently, the intracellular levels of perforin, granzymes, and granulysin determined by flow cytometry have also been used in the evaluation of NK cell function. This chapter will describe the methods for NK cell assays in immunotoxicity testing.

Toxic nuclear effects of the organophosphorus insecticide Dichlorvos (DDVP) in human peripheral blood lymphocytes

Organophosphorus insecticides are used worldwide in the control of agricultural, household and veterinary pests. Dichlorvos (2,2-dichlorovinyl dimethyl phosphate) is a commonly used organophosphorus insecticide. In this study, in order to elucidate the toxic nuclear effects of dichlorvos, freshly isolated human peripheral blood lymphocytes were incubated with 5, 10, 20, 40, 80 and 100 microg/mL of dichlorvos. According to the results, dichlorvos induced micronuclei, decreased the mitotic and replication indexes. It is a genotoxic product causing chromosomal damage (an increase in micronucleus) and cell death (decrease in mitotic and replication indexes).

Evaluation of granulysin and perforin as candidate biomarkers for protection following vaccination with Mycobacterium bovis BCG or M. bovisDeltaRD1

The development of improved vaccines against tuberculosis (TB) is directly linked to the investigation of new and better correlates of protection after vaccination against TB. Cloning and characterization of bovine homologues of the antimicrobial protein granulysin (Bo-lysin) and perforin by our group could be used as potential biomarkers for TB vaccination efficacy. In the present study, we examined the kinetics of granulysin, perforin, IFNgamma and Fas-L responses to Mycobacterium bovis purified protein derivative (PPD) stimulation by peripheral blood mononuclear cells from M. bovisDeltaRD1-, BCG- and non-vaccinated cattle. Gene expression profiles following PPD stimulation showed significant increases in transcripts for granulysin and IFNgamma in both CD4(+) and CD8(+) T cells in BCG-vaccinated as compared with non-vaccinated animals. Perforin and IFNgamma examined by flow cytometry, showed a difference of 1-2% more PPD-specific cells in BCG-vaccinated than non-vaccinated animals. In the vaccine trial, granulysin and perforin were significantly increased in both vaccine groups as compared with control after vaccination and challenge. IFNgamma expression was increased only after vaccination and secretion was higher in the control, non-protected group as compared with both vaccine groups demonstrating no correlation with protection upon vaccination. In summary, results shown here provide evidence that granulysin and perforin are prospective candidates as biomarkers of protection after vaccination against TB.

Visiting a forest, but not a city, increases human natural killer activity and expression of anti-cancer proteins

We previously reported that a forest bathing trip enhanced human NK activity, number of NK cells, and intracellular anti-cancer proteins in lymphocytes. In the present study, we investigated how long the increased NK activity lasts and compared the effect of a forest bathing trip on NK activity with a trip to places in a city without forests. Twelve healthy male subjects, age 35-56 years, were selected with informed consent. The subjects experienced a three-day/two-night trip to forest fields and to a city, in which activity levels during both trips were matched. On day 1, subjects walked for two hours in the afternoon in a forest field; and on day 2, they walked for two hours in the morning and afternoon, respectively, in two different forest fields; and on day 3, the subjects finished the trip and returned to Tokyo after drawing blood samples and completing the questionnaire. Blood and urine were sampled on the second and third days during the trips, and on days 7 and 30 after the trip, and NK activity, numbers of NK and T cells, and granulysin, perforin, and granzymes A/B-expressing lymphocytes in the blood samples, and the concentration of adrenaline in urine were measured. Similar measurements were made before the trips on a normal working day as the control. Phytoncide concentrations in forest and city air were measured. The forest bathing trip significantly increased NK activity and the numbers of NK, perforin, granulysin, and granzyme A/B-expressing cells and significantly decreased the concentration of adrenaline in urine. The increased NK activity lasted for more than 7 days after the trip. In contrast, a city tourist visit did not increase NK activity, numbers of NK cells, nor the expression of selected intracellular anti-cancer proteins, and did not decrease the concentration of adrenaline in urine. Phytoncides, such as alpha-pinene and beta-pinene were detected in forest air, but almost not in city air. These findings indicate that a forest bathing trip increased NK activity, number of NK cells, and levels of intracellular anti-cancer proteins, and that this effect lasted at least 7 days after the trip. Phytoncides released from trees and decreased stress hormone may partially contribute to the increased NK activity.

Forest bathing enhances human natural killer activity and expression of anti-cancer proteins

In order to explore the effect of forest bathing on human immune function, we investigated natural killer (NK) activity; the number of NK cells, and perforin, granzymes and granulysin-expression in peripheral blood lymphocytes (PBL) during a visit to forest fields. Twelve healthy male subjects, age 37-55 years, were selected with informed consent from three large companies in Tokyo, Japan. The subjects experienced a three-day/two-night trip in three different forest fields. On the first day, subjects walked for two hours in the afternoon in a forest field; and on the second day, they walked for two hours in the morning and afternoon, respectively, in two different forest fields. Blood was sampled on the second and third days, and NK activity; proportions of NK, T cells, granulysin, perforin, and granzymes A/B-expressing cells in PBL were measured. Similar measurements were made before the trip on a normal working day as the control. Almost all of the subjects (11/12) showed higher NK activity after the trip (about 50 percent increased) compared with before. There are significant differences both before and after the trip and between days 1 and 2 in NK activity. The forest bathing trip also significantly increased the numbers of NK, perforin, granulysin, and granzymes A/B-expressing cells. Taken together, these findings indicate that a forest bathing trip can increase NK activity, and that this effect at least partially mediated by increasing the number of NK cells and by the induction of intracellular anti-cancer proteins.

Effect of Rhaphidophora korthalsii methanol extract on human peripheral blood mononuclear cell (PBMC) proliferation and cytolytic activity toward HepG2

The study of bioactivity of natural product is one of the major researches for drug discovery. The aim of this finding was to study the proliferation effect of Rhaphidophora korthalsii methanol extract on human PBMC and subsequently the cytotoxic effect of activated PBMC toward HepG2 human hepatocellular carcinoma. In this present study, MTT assay, cell cycle study and Annexin 5 binding assay were used to study the immunomodulatory and cytotoxic effects. In vitro cytotoxic screening of Rhaphidophora korthalsii methanol extract showed that the extract was non-toxic against hepatocellular carcinoma (HepG2). In contrast, the extract was able to stimulate the proliferation of human PBMC at 48 h and 72 h in MTT assay and cell cycle progress study. The application of immunomodulator in tumor research was studied by using MTT microcytotoxicity assay and flow cytometric Annexin V. Results indicated that pre-treated PBMC with Rhaphidophora korthalsii methanol extract induced the highest cytotoxicity (44.87+/-6.06% for MTT microcytotoxicity assay and 51.51+/-3.85% for Annexin V) toward HepG2. This finding demonstrates that Rhaphidophora korthalsii methanol extract are potent to stimulate the cytotoxic effect of immune cells toward HepG2.

DDVP markedly decreases the expression of granzyme B and granzyme 3/K in human NK cells

Natural killer (NK), lymphokine-activated killer (LAK), and cytotoxic T lymphocyte (CTL) cells kill target cells by the directed release of cytolytic granules that contain perforin, granzymes, and granulysin. We have found previously that dimethyl 2,2-dichlorovinyl phosphate (DDVP, dichlorvos), an organophosphorus pesticide, significantly decreased the expression of perforin, granzyme A (GrA), and granulysin and inhibited NK, LAK, and CTL activities. To further explore the mechanism of organophosphorus pesticide-induced inhibition of cell-mediated cytolysis, we examined whether organophosphorus pesticides affect the expression of GrB and Gr3/K in NK cells. We used an interleukin-2 (IL-2) independent human NK cell line, NK-92CI. We confirmed that NK-92CI cells express intracellular GrB and Gr3/K by flow cytometry, that NK-92CI cells are highly cytotoxic to K562 cells with a chromium release assay, and that DDVP significantly inhibited cytolytic activity of NK-92CI cells in a dose- and time-dependent manner. We found that DDVP significantly decreased the expression of GrB and Gr3/K in NK-92CI cells in a dose- and time-dependent manner by flow cytometry. Immunocytochemical results showed that DDVP significantly decreases the level of GrB positive granules in NK-92CI cells, which may be due to degranulation. Taken together, DDVP significantly inhibits NK activity and reduces the intracellular GrB and Gr3/K levels in NK cells.

New mechanism of organophosphorus pesticide-induced immunotoxicity

Organophosphorus pesticides (OPs) are widely used throughout the world as insecticides in agriculture and as eradicating agents for termites around homes. The main toxicity of OPs is neurotoxicity, which is caused by the inhibition of acetylcholinesterase. OPs also affect the immune response, including effects on antibody production, interleukin-2 production, T cell proliferation, decrease of CD5 cells, and increases of CD26 cells and autoantibodies, Th1/Th2 cytokine profiles, and the inhibition of natural killer (NK) cell, lymphokine-activated killer (LAK) cell, and cytotoxic T lymphocyte (CTL) activities. However, there have been few studies of the mechanism of OP-induced immunotoxicity, especially the mechanism of OP-induced inhibition of cytolytic activity of killer cells. This study reviews new mechanisms of OP-induced inhibition of the activities of NK cells, LAK cells, and CTLs. It has been reported that NK cells, LAK cells, and CTLs induce cell death in tumors or virus-infected target cells by two main mechanisms. The first mechanism is direct release of cytolytic granules that contain the pore-forming protein perforin, several serine proteases termed granzymes, and granulysin by exocytosis to kill target cells, which is called the granule exocytosis pathway. The second mechanism is mediated by the Fas ligand (Fas-L)/Fas pathway, in which FasL (CD95 L), a surface membrane ligand of the killer cell cross links with the target cell's surface death receptor Fas (CD95) to induce apoptosis of the target cells. To date, it has been reported that OPs inhibit NK cell, LAK cell, and CTL activities by at least the following three mechanisms: 1) OPs impair the granule exocytosis pathway of NK cells, LAK cells, and CTLs by inhibiting the activity of granzymes, and by decreasing the intracellular levels of perforin, granzyme A, and granulysin, which were mediated by inducing degranulation of NK cells and by inhibiting the transcription of the mRNAs of perforin, granzyme A, and granulysin. 2) OPs impair the FasL/Fas pathway of NK cells, LAK cells, and CTLs, as investigated by using perforin-knockout mice, in which the granule exocytosis pathway of NK cells does not function and only the FasL/Fas pathway remains functional. 3) OPs induce apoptosis of immune cells.

Organophosphorus pesticides induce apoptosis in human NK cells

We found previously that organophosphorus pesticides (OPs) significantly inhibited natural killer (NK) activity. To explore the mechanism of OP-induced inhibition of NK activity, we investigated whether OPs can induce apoptosis in NK cells in the present study. We used NK-92CI and NK-92MI cells, which are interleukin-2 independent human NK cell lines. NK-92CI and/or NK-92MI were treated with dichlorvos (DDVP) or chlorpyrifos (CP) at 0-100 ppm for 1-72 h at 37 degrees C in vitro. Apoptosis induced by DDVP and CP was determined by FITC-Annexin V staining and the intracellular level of active caspase-3 was analysed by flow cytometry. We found that DDVP and CP significantly induced apoptosis in NK-92CI and NK-92MI cells in a dose- and time-dependent manner. DDVP also induced an increase of intracellular active caspase-3 in NK-92CI in a dose- and time-dependent manner, and a caspase-3 inhibitor, Z-DEVD-FMK, significantly inhibited DDVP-induced apoptosis, suggesting that this apoptosis is partially mediated by activation of intracellular caspase-3. The pattern of apoptosis induced by CP differed from that induced by DDVP. CP showed a faster response than DDVP at higher doses; whereas, DDVP showed a slower, but stronger apoptosis-inducing ability than CP at lower doses. Moreover, the response to OPs differed between NK-92CI and NK-92MI cells, and NK-92CI was more sensitive to OPs than NK-92MI. This is similar to the inhibition of NK activity induced by DDVP, in which NK-92CI was more easily inhibited by DDVP than NK-92MI. Taken together, these findings suggest that OP-induced inhibition of NK activity may be at least partially mediated by OP-induced apoptosis in NK.

Healthy lifestyles are associated with higher levels of perforin, granulysin and granzymes A/B-expressing cells in peripheral blood lymphocytes

OBJECTIVE

It is well documented that natural killer (NK) cells provide host defense against tumors and viruses. We previously showed that lifestyle affects human NK and LAK activities. In order to explore the underlying mechanism, we investigated the effect of lifestyle on intracellular perforin, granulysin, and granzymes A/B in peripheral blood lymphocytes (PBL).

METHODS

114 healthy male subjects, aged 20-59 years, from a large company in Osaka, Japan were selected with informed consent. The subjects were divided into groups reporting good, moderate, and poor lifestyles according to their responses on a questionnaire regarding eight health practices (cigarette smoking, alcohol consumption, sleeping hours, working hours, physical exercise, eating breakfast, balanced nutrition, and mental stress). Peripheral blood was taken, and numbers of NK, T, perforin, granulysin, and granzymes A/B-expressing cells in PBL were measured by flow cytometry.

RESULTS

Subjects with good or moderate lifestyle showed significantly higher numbers of NK, and perforin, granulysin, and granzymes A/B-expressing cells and a significantly lower number of T cells in PBL than subjects with poor lifestyle. Among the eight health practices, cigarette smoking, physical exercise, eating breakfast, and balanced nutrition significantly affect the numbers of NK, T cells, perforin, granulysin, and/or granzymes A/B-expressing cells, and alcohol consumption significantly affects the number of granzyme A-expressing cells. On the other hand, mental stress, sleeping, and working hours had no effect on those parameters.

CONCLUSIONS

Taken together, these findings indicate that poor lifestyle significantly decreases the numbers of NK, perforin, granulysin, and granzymes A/B-expressing cells in PBL.

Phytoncides (wood essential oils) induce human natural killer cell activity

To explore the effect of forest bathing on the human immune system, we investigated the effect of phytoncides (wood essential oils) on natural killer (NK) activity and the expression of perforin, granzyme A and granulysin in human NK cells. We used NK-92MI cell, an interleukin-2 independent human NK cell line derived from the NK-92 cell, in the present study. NK-92MI cells express the CD56 surface marker, perforin, granzyme A, and granulysin by flow cytometry and are highly cytotoxic to K562 cells in chromium release assay. Phytoncides significantly increase cytolytic activity of NK-92MI cells in a dose-dependent manner and significantly increase the expression of perforin, granzyme A, and granulysin in the NK-92MI cells. Phytoncides also partially, but significantly, restore the decreased human NK activity and the decreased perforin, granzyme A, and granulysin expression in NK-92MI cells induced by dimethyl 2,2-dichlorovinyl phosphate (DDVP), an organophosphorus pesticide. Pretreatment with phytoncides partially prevents DDVP-induced inhibition of NK activity. Taken together, these data indicate that phytoncides significantly enhance human NK activity and this effect is at least partially mediated by induction of intracellular perforin, granzyme A, and granulysin.

Chlorpyrifos induces apoptosis in human monocyte cell line U937

In order to investigate chlorpyrifos-induced cell death and its underlying mechanism in human immune cells, a human monocyte like cell line (U937) was treated with chlorpyrifos at 4.45-570microM for 0.5-24h at 37 degrees Celsius in a 5% CO(2) incubator. We first found that chlorpyrifos induced cell death of U937 in a dose- and time-dependent manner, as shown by LDH and MTT assays and PI uptake. Then, we investigated if chlorpyrifos-induced cell death consisted of apoptosis, as determined by analysis of Annexin-V staining and the intracellular level of active caspase-3 by flow cytometry, and DNA fragmentation analysis. We found that chlorpyrifos induced apoptosis in U937 in a time- and dose-dependent manner, as shown by Annexin-V staining. DNA fragmentation was detected when cells were treated with 71 to 284microM chlorpyrifos for 4 or 6h. Chlorpyrifos also induced an increase of intracellular active caspase-3 in U937 cells in a dose-dependent manner, and a caspase-3 inhibitor, Z-DEVD-FMK, significantly inhibited the chlorpyrifos-induced apoptosis. These findings indicate that chlorpyrifos can induce apoptosis in U937 cells, and this effect is partially mediated by activation of intracellular caspase-3.

Effect of electric foot shock and psychological stress on activities of murine splenic natural killer and lymphokine-activated killer cells, cytotoxic T lymphocytes, natural killer receptors and mRNA transcripts for granzymes and perforin

To explore the mechanism of stress-induced inhibition of natural killer (NK) activity, female C57BL/6 mice were stimulated by electric foot shock and psychological stress for 7 days consecutively. The shocked mice received scrambled, uncontrollable, inescapable 0.6 mA electric shocks in a communication box 120 times during 60 min. The mice in the psychological stress group were put into the communication box without electric foot shock. The plasma corticosterone level in both stressed groups was significantly higher than that in controls on days 1, 3, 5 and 7 and showed the highest level on day 3 in the foot shock stress. According to these results, therefore, we investigated the effect of stress on immunological function on day 3, and measured body weight, weight of the spleen, number of splenocytes, splenic NK, lymphokine-activated killer (LAK) and cytotoxic T lymphocyte (CTL) activities, NK receptors, and mRNA transcripts for granzymes A and B and perforin in splenocytes. The NK, LAK and CTL activities, and NK receptors in mice with both types of stress were significantly decreased compared to those of the control mice, but the decreases were greater in the foot-shocked mice than in the psychological-stress mice. The mRNA transcripts for granzyme A and perforin were significantly decreased only in the foot-shocked mice. On the other hand, the foot-shock stress increased granzyme B. The above findings suggest that stress induced inhibition of NK, LAK and CTL activities partially via affecting NK receptors, granzymes and perforin.