Humoral and cell mediated immune response to cadmium in mice

MiR-182-5p/TLR4/NF-κB axis contributes to the protective effect of caffeic acid phenethyl ester against cadmium-induced spleen toxicity and associated damage in mice

Cadmium (Cd) is a toxic heavy metal pollutant that can be accumulated in organs including the spleen, thereby threatening human health. In this study, the effect of caffeic acid phenethyl ester (CAPE, a bioactive component of honeybee propolis) on CdCl2-induced spleen toxicity and underlying mechanisms were examined in mice. Histological examinations revealed that CAPE (10 μmol/kg/day b.w.) could mitigate spleen damage induced by CdCl2 (1.5 mg/kg/day b.w.) in mice. Compared to the mice treated only by CdCl2, CAPE administration increased the body weight while decreasing the spleen weight, spleen Cd content and spleen to body ratio of the CdCl2-treated mice. Western blot and ELISA tests revealed that CAPE suppressed CdCl2-induced inflammation (indicated by the decreases in the levels of inflammatory indictors). TUNEL and Western blot results showed that CAPE suppressed CdCl2-induced apoptosis through reducing the percentage of TUNEL-positive cells and regulating apoptosis factors. The antagonistic effect of CAPE against CdCl2-induced spleen toxicity was realized by increasing miR-182-5p expression to regulate the TLR4/NF-κB pathway. Therefore, CAPE could be a food-derived spleen protector to counteract Cd-induced spleen toxicity through alleviating apoptosis and inflammation via the miR-182-5p/TLR4/NF-κB axis.

Cadmium induces the thymus apoptosis of pigs through ROS-dependent PTEN/PI3K/AKT signaling pathway

Cadmium (Cd) is a transition metal that is toxic to living organisms in the environment and endangers living organisms. To explore whether Cd induces apoptosis in pig thymus and its possible mechanism, the role Cd induction of the PTEN/PI3K/Akt pathway in apoptosis of thymus cells was studied in pigs. We found that Cd exposure (the feed is treated with Cd) significantly increased Cd accumulation in the thymus of pigs. The TUNEL assay confirmed the typical apoptotic characteristics of thymus in Cd group. Moreover, in the Cd group, the activities of antioxidant indices decreased significantly, while the levels of oxidative stress indexes increased significantly, and the mRNA levels of GSH, CAT, Gpx1, GST, SOD1, and SOD2 decreased obviously. Moreover, the mRNA and protein levels of PTEN/PI3K/AKT and apoptosis-related genes were detected by qPCR and western blotting. The results show that the expressions of PI3K and AKT decreased, while the expression of PTEN increased, indicating that pathway activated. With the PTEN/PI3K/AKT pathway regulating, Bcl-2 expression decreased. Conversely, the mRNA and protein expression of apoptosis-related genes were up-regulated. In conclusion, accumulation of Cd in the pigs caused oxidative damage to immune tissues. In addition, Cd-induced oxidative stress activates the PTEN/PI3K/AKT pathway, inducing apoptosis in the thymus of pigs.

Effects of Cadmium Exposure on the Immune System and Immunoregulation

Cadmium (Cd), a biologically non-essential heavy metal, is widespread in the environment, including the air, water, and soil, and is widely present in foods and quantum dot preparations. Cd enters the body primarily through inhalation and ingestion. Its biological half-life in humans is 10-35 years; therefore, Cd poses long-term health risks. While most studies on Cd toxicity have focused on organ and tissue damage, the immunotoxicity of Cd has drawn increasing attention recently. Cd accumulates in immune cells, modulates the function of the immune system, triggers immunological responses, and leads to diverse health problems. Cd acts as an immunotoxic agent by regulating the activity and apoptosis of immune cells, altering the secretion of immune cytokines, inducing reactive oxygen species (ROS) production and oxidative stress, changing the frequency of T lymphocyte subsets, and altering the production of selective antibodies in immune cells. This review summarizes the immunological toxicity of Cd, elucidates the mechanisms underlying Cd toxicity in terms of innate immunity and adaptive immunity, and discusses potential strategies to alleviate the adverse effects of Cd on the immune system.

High serum IgG subclass concentrations in children with e-waste Pb and Cd exposure

Immunoglobulin G (IgG) is the predominant component of the humoral immune system. Epidemiological studies have shown that lead (Pb) or cadmium (Cd) exposure is associated with changes in human IgG levels, and alteration of IgG subclass production can be induced by differential modulation of Th1 and Th2 cytokines caused by Pb or Cd exposure. However, no study has focused on the adverse effects of Pb and Cd co-exposure on IgG subclass production by regulating Th1/Th2 cytokines in children living in electronic waste (e-waste) areas. This study aims to analyze the associations among Pb and Cd in blood, Th1/Th2 cytokines, and IgG subclasses in serum from children. A total of 181 healthy, 2- to 7-year-old children were examined. Of them, 104 were from Guiyu (e-waste exposed group), and the rest were from Haojiang (reference group) in China. Pb and Cd levels in whole blood, cytokines, and IgG subclasses in serum were determined. Exposed children had higher levels of blood Pb and Cd, serum IgG1, IgG1 + IgG2, serum Th1 cytokine interferon-γ (IFN-γ) and lower levels of the Th2 cytokine interleukin (IL)-13. Increased blood Pb levels were positively associated with serum levels of IFN-γ, and negatively associated with serum levels of IL-13. Adjusted linear regression analysis showed that serum levels of IL-13 were negatively associated with serum levels of IgG1 and IgG1 + IgG2. Mediation models indicated that IL-13 had significant mediating effects on the relationships between blood Pb levels and serum IgG1, as well as between blood Pb levels and serum IgG1 + IgG2. Increased blood Cd levels were positively associated with serum levels of IgG1. Our results show heavy metal (particularly Pb) exposure may affect IgG subclass production by regulating Th1/Th2 cytokines in exposed children, thus providing new evidence for a relationship between humoral immune function and environmental exposure.

Immunotoxicology of cadmium: Cells of the immune system as targets and effectors of cadmium toxicity

Cadmium (Cd) has been listed as one of the most toxic substances affecting numerous tissues/organs, including the immune system. Due to variations in studies examining Cd effects on the immune system (exposure regime, experimental systems, immune endpoint measured), data on Cd immunotoxicity in humans and experimental animals are inconsistent. However, it is clear that Cd can affect cells of the immune system and can modulate some immune responses. Due to the complex nature of the immune system and its activities which are determined by multiple interactions, the underlying mechanisms involved in the immunotoxicity of this metal are still vague. Here, the current knowledge regarding the interaction of Cd with cells of the immune system, which may affect immune responses as well as potential mechanisms of consequent biological effects of such activities, is reviewed. Tissue injury caused by Cd-induced effects on innate cell activities depicts components of the immune system as mediators/effectors of Cd tissue toxicity. Cd-induced immune alterations, which may compromise host defense against pathogenic microorganisms and homeostatic reparative activities, stress this metal as an important health hazard.

Protective effects of Ganoderma lucidum triterpenoids on oxidative stress and apoptosis in the spleen of chickens induced by cadmium

Cadmium (Cd) is a heavy metal that poses a huge potential threat to human and animal health. Therefore, it is necessary to study its damage mechanism. In the present study, we have examined the protective effects of Ganoderma lucidum triterpenoids on oxidative stress and apoptosis in the spleen of chickens induced by Cd. One hundred and twenty healthy Hailan white chickens (7-day-old) were randomly divided into the following four groups: control group, Cd group, triterpenoid group, and Cd-triterpenoid group. The chickens were euthanized on the 20th, 40th, and 60th days, and the spleens were removed. Cd and malondialdehyde (MDA) content, antioxidant enzyme (superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px)) activities, and inflammatory factor (tumor necrosis factor alpha (TNF-α) and interleukin (IL-1β and IL-6)) and apoptotic factor (caspase-3, BAX, and Bcl-2) expressions were detected. The results showed that Ganoderma lucidum triterpenoids could reduce the content of Cd and MDA; increase the antioxidant enzyme activities (SOD and GSH-Px); decrease the expression of inflammatory factors (TNF-α) and interleukin (IL-1β and IL-6); increase the expression of apoptotic factor (Bcl-2); and decrease the expression of apoptotic factors (caspase-3 and Bax). It showed that the triterpenoids of Ganoderma lucidum had significant protective effects on oxidative stress and apoptosis of chicken spleen, which provided a theoretical basis for further prevention and treatment of cadmium poisoning.

Inhibition of Autophagy Alleviates Cadmium-Induced Mouse Spleen and Human B Cells Apoptosis

Cadmium (Cd) is a toxic heavy metal that can accumulate and cause severe damage to many organs, such as liver, kidney, lung, etc. Cd also significantly suppresses immunity, however, the underlying mechanism involved in Cd-induced immunnotoxicity is still unclear. The present study indicated that semichronic Cd exposure (7 days) induced apoptotic damage of mouse spleen. In human Ramos B cells, Cd exposure also induced apoptosis, which was dependent on Cd-induced vacuole membrane protein 1 (VMP1) expression and autophagy. Cd-induced autophagy and apoptosis were abated when VMP1 expression was knockdown. In addition, Cd-induced VMP1 expression, autophagy, and apoptosis were dependent on the elevation of Ca2+ and reactive oxygen species (ROS). More important, Cd exposure also induced VMP1 expression and autophagy in mouse spleen tissue, and the intraperitoneal injection of the autophagy inhibitor chloroquine (CQ) into mice effectively reduced Cd-induced spleen apoptotic damage. Taken together, these results indicate Cd-induced autophagy, promotes apoptosis in immune cells, and inhibition of autophagy can alleviate Cd-induced spleen and immune cell apoptosis. This study might provide the groundwork for future studies on Cd-induced immunomodulatory effects and immune diseases.

Chronic low-level cadmium exposure in rats affects cytokine production by activated T cells

Cadmium is a toxic metal and common environmental contaminant. Chronic cadmium exposure results in kidney, bone, reproductive, and immune toxicity as well as cancer. Cadmium induces splenomegaly and affects the adaptive immune system, but specific effects vary depending on the dose, model, and endpoint. This study investigates the effects of subchronic, oral, and low-dose cadmium exposure (32 ppm cadmium chloride in drinking water for 10 weeks) on the rat immune system, focusing on T cell function. Cadmium-exposed animals demonstrated slight increases in the spleen-to-body weight ratios, and decreases in overall splenic cell numbers and markers of oxidative stress. The relative ratios of splenic cell populations remained similar, except for modest increases in regulatory T cells in the cadmium-exposed animals. Cadmium exposure also significantly increased the production of IFNγ, a pro-inflammatory cytokine, and IL-10, a cytokine produced by multiple T cell subsets that typically inhibits IFNγ expression, by activated T cells. The increase in IFNγ and IL-10 suggests that cadmium exposure may affect multiple T cell subsets. Collectively, this study suggests that subchronic, low-dose cadmium exposure impacts both immune cell function and cellularity, and may enhance inflammatory responses.

The protective role of selenium against cadmium-induced hepatotoxicity in laying hens: Expression of Hsps and inflammation-related genes and modulation of elements homeostasis

The purpose of this study was to examine the potential role of high selenium (Se) diets in alleviating chronic cadmium (Cd) hepatic toxicity in laying hens. In the present study, 128 healthy 31-week-old laying hens were fed a diet supplemented with Se (Na₂SeO₃, 2 mg/kg), Cd (CdCl₂, 150 mg/kg), or both Se and Cd (150 mg/kg of CdCl₂ and 2 mg/kg of Na₂SeO₃) for 90 days. The expression levels of heat shock proteins (Hsps, including Hsp60, Hsp70 and Hsp90) and inflammation-related factors, including nuclear factor-kappa B p50 (NF-κB), cyclooxygenase-2 (COX-2), prostaglandin E synthases (PTGES), interleukin 1-beta (IL-1β), and tumor necrosis factor-α (TNF-α) were investigated. The concentrations of 28 elements were also determined. The results indicated that Cd treatment significantly increased the mRNA and protein expression levels of Hsps and significantly improved the expression of inflammation-related genes. Moreover, Cd addition to the diets resulted in disturbances in the systemic balance of 13 elements, leading to decrease in the concentrations of Cr, Mn, Sr, Ba, and Hg and increase in Li, B, Ca, Ti, Fe, Cu, Mo, and Cd concentrations. Treatment with Se significantly alleviated Cd-induced hepatic toxicity, as evidenced by a reduction in Hsp60, Hsp70, Hsp90, NF-κB, COX-2, PTGES, TNF-α, and IL-1β expression. Additionally, Se and Cd co-treatment alleviated the changes in Li, B, Ca, Fe, Ti, Cu, Mo, Cd, Cr, Se, Sr, Ba, and Hg concentrations, which was in contrast to that upon Cd induction. The study indicated that Se could help against the negative effects of Cd and may be related to the alleviation of Cd-induced Hsps stress and the inflammatory responses along with modulating the element homeostasis.

Cadmium induces BNIP3-dependent autophagy in chicken spleen by modulating miR-33-AMPK axis

Cadmium (Cd), a widespread environmental pollutant, has toxic effects on organs including spleen. However, the underlying mechanisms of Cd induced spleen toxicity and the roles of micro-RNA (miRNA) in this process remain poorly understood. To investigate this, cadmium chloride (CdCl₂, 10 mg/kg) was administered in the diet of chickens for 90 days. Electron microscopy, qPCR and Western blot were performed. Results showed that Cd exposure suppressed miR-33-5q which increased the levels of AMPK. Subsequently, significant decrease in AKT/mTOR signaling and HSP70 were observed. Concurrently, levels of NF-κB, p-JNK/JNK increased significantly. Moreover, the expression of BNIP3 and other autophagy markers (LC3-I, LC3-II, Beclin-1) increased significantly. Additionally, the levels of ions (Ca, Cr, Se, Sr, Sn, Ba) and (Na, Mg, V, Fe, Mo, Cu, Zn, Cd) significantly decreased and increased, respectively. Taken together, we conclude that Cd induced the deregulation of miR-33-AMPK axis led to BNIP3-dependent autophagy in chicken spleen through AKT/mTOR and HSP70-NF-κB/JNK signal pathways. In-addition Cd could affect ion homeostasis in chicken spleen.

Selenium antagonizes cadmium-induced apoptosis in chicken spleen but not involving Nrf2-regulated antioxidant response

The nuclear transcription factor NF-E2-related factor 2 (Nrf2) binds to antioxidant response elements (AREs) and is involved in the regulation of genes participated in defending cells against oxidative damage, which have been confirmed in animal models. Selenium (Se), known as an important element in the regulation of antioxidant activity, can antagonize Cadmium (Cd) toxicity in birds. However, the role of Nrf2 in selenium-cadmium interaction has not been reported in birds. To further explore the mechanism of selenium attenuating spleen toxicity induced by cadmium in chickens, cadmium chloride (CdCl₂, 150mg/kg) and sodium selenite (Na₂SeO₃, 2mg/kg) were co-administrated or individually administered in the diet of chickens for 90 days. The results showed that Cd exposure increased the level of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) and decreased the antioxidant enzyme activities, including superoxide dismutase (SOD), glutathione peroxidase (Gpx), total antioxidative capacity (T-AOC), catalase (CAT). Cd exposure increased obviously nuclear accumulation of Nrf2, and the expression of Nrf2 downstream heme oxygenase-1 (HO-1) and NAD(P)H: quinine oxidoreductase 1 (NQO1), reduced the expression of Kelch-like ECH-associated protein (keap1), Gpx-1 and thioredoxin reductase-1 (TrxR1). In addition, Cd induced the increase of bak, caspase9, p53, Cyt c mRNA levels, increased bax/bcl-2 ratio, increased caspase3 mRNA and protein levels. Selenium treatment reduced the accumulation of Cd in the spleen, attenuates Cd-induced Nrf2 nuclear accumulation, enhanced antioxidant enzyme activities, ameliorated Cd-induced oxidative stress and apoptosis in the spleen. In summary, our results demonstrate that Se ameliorated spleen toxicity induced by cadmium by modulating the antioxidant system, independently of Nrf2-regulated antioxidant response pathway.

Cadmium modulates hematopoietic stem and progenitor cells and skews toward myelopoiesis in mice

The heavy metal cadmium (Cd) is known to modulate immunity and cause osteoporosis. However, how Cd influences on hematopoiesis remain largely unknown. Herein, we show that wild-type C57BL/6 (B6) mice exposed to Cd for 3months had expanded bone marrow (BM) populations of long-term hematopoietic stem cells (LT-HSCs), common myeloid progenitors (CMPs) and granulocyte-macrophage progenitors (GMPs), while having reduced populations of multipotent progenitors (MPPs) and common lymphoid progenitors (CLPs). A competitive mixed BM transplantation assay indicates that BM from Cd-treated mice had impaired LT-HSC ability to differentiate into mature cells. In accordance with increased myeloid progenitors and decreased lymphoid progenitors, the BM and spleens of Cd-treated mice had more monocytes and/or neutrophils and fewer B cells and T cells. Cd impaired the ability of the non-hematopoietic system to support LT-HSCs, in that lethally irradiated Cd-treated recipients transplanted with normal BM cells had reduced LT-HSCs after the hematopoietic system was fully reconstituted. This is consistent with reduced osteoblasts, a known critical component for HSC niche, observed in Cd-treated mice. Conversely, lethally irradiated control recipients transplanted with BM cells from Cd-treated mice had normal LT-HSC reconstitution. Furthermore, both control mice and Cd-treated mice that received Alendronate, a clinical drug used for treating osteoporosis, had BM increases of LT-HSCs. Thus, the results suggest Cd increase of LT-HSCs is due to effects on HSCs and not on osteoblasts, although, Cd causes osteoblast reduction and impaired niche function for maintaining HSCs. Furthermore, Cd skews HSCs toward myelopoiesis.

Effects of selenium and cadmium on changes in the gene expression of immune cytokines in chicken splenic lymphocytes

Cadmium (Cd) is an environmental pollutant that is considered to be a potent toxin to organisms. Selenium (Se) has been known for its concomitant biological effects and characteristics with Cd. Due to the lack of the research regarding how the duality of Cd/Se affects immune cytokines in poultry, this paper aims to partly tackle this question. Chicken splenic lymphocytes with Cd (10(-6) mol/L CdCl2), Se (10(-7) mol/L Na2SeO3), Cd + Se (10(-7) mol/L Na2SeO3 and 10(-6) mol/L CdCl2), and a control group were incubated for 12, 24, 36, 48, and 60 h, respectively. At each time point, the cells were collected and the messenger RNA (mRNA) expression levels of interleukin (IL)-1β, IL-2, IL-4, IL-10, IL-17, and interferon-γ (IFN-γ) were also examined. Compared with the control group and the Se-alone-treated group, the mRNA expression levels of IL-2, IL-4, IL-10, IL-17, and IFN-γ decreased significantly in the Cd-alone-treated group. By contrast, the mRNA expression level of IL-1β markedly increased. Levels of IL-2, IL-4, IL-10, IL-17, and IFN-γ in Cd + Se-treated groups were significantly higher than those in Cd-alone-treated groups; however, the levels were not as high as the Se-alone-treated groups and the control group. The mRNA expression level of IL-1β in the Cd + Se-treated group was lower than in the Cd-alone-treated group. The relationships with IL-2, IL-4, and IL-10 were found to be closer in the PC 1 matrix and 3D plot of the principal component analysis (PCA) loadings. IL-17 and IFN-γ were closer in the matrix of PC 2. However, IL-1β gene expression appeared to be isolated in the matrix of PC 3. In addition, the results of cytokine cluster analysis showed that IL-2, IL-4, IL-10, IL-17, and IFN-γ were in the first group and that IL-1β was in the second group. Therefore, Se partly attenuate immune toxicity induced by Cd in chicken splenic lymphocytes.

Chemoprotective effect of monoisoamyl 2, 3-dimercaptosuccinate (MiADMS) on cytokines expression in cadmium chloride treated human lung cells

Cadmium is commercially profitable element, but it causes toxicity in humans and animals leading to diseases in various organs. The main route of cadmium exposure to humans is through inhalation. Lungs respond to insult through secretion of cytokines. In this study, the chemoprotective effect of monoisoamyl 2, 3-dimercaptosuccinate (MiADMS) was evaluated on viability and cytokines expression in CdCl2 treated human lung A549 cells by cytokine array. Cells were treated with 0, 50, 75, and 100 µM CdCl2 alone, 300 µM MiADMS alone, and co-treated with 300 µM MiADMS and 75 µM CdCl2 for 24 h. The viability was measured by crystal violet dye. The level of cytokines in the cells' lysate and cell culture medium was measured using Ray Biotech's Human Cytokine Array 6 in control cells, 75 µM CdCl2 alone and MiADMS co-treated cells. Array results were validated by ELISA kit. The CdCl2 caused a dose dependent decrease in cell viability, while MiADMS co-treatment resulted in a significant increase in viability of CdCl2 treated cells. Morphology of the cells treated with CdCl2 was destroyed, while MiADMS restored the lost shape in CdCl2 treated cells. In addition, the cells co-treated with MiADMS and CdCl2 showed modulation of cytokines expression in comparison to the CdCl2 alone treated cells. The ELISA results showed the similar pattern of cytokine expression as Human Cytokine Array and validated the array results. These results clearly show the chemoprotective effect of MiADMS and suggest that MiADMS can be used as antidote at moderate dose against CdCl2 toxicity.

Brain most susceptible to cadmium induced oxidative stress in mice

Accumulated evidence over the years indicate that cadmium (Cd) may be a possible etiological factor for neurodegenerative diseases. This may possibly be linked to excessive generation of free radicals that damages the organs in the body depending on their defence mechanism. Since Cd is a toxic agent that affect several cell types, the aim of this study was to shed light on the effect of Cd and its consequences on different organs of the mice body. To test the hypothesis of concentration dependent Reactive Oxygen Species (ROS) generation and DNA damage, observations were done in the serum of 4-5 weeks old male Swiss albino mice by treating with cadmium chloride (CdCl2) in drinking water for 30 days. The expression of Bcl-2-associated X protein (Bax) an apoptotic marker protein was two times higher in brain compared to liver at an exposure level of 0.5mgL(-1) CdCl2. Furthermore the correlation and linkage data analysis of antioxidant defence system revealed a rapid alteration in the brain, compared to any other organs considered in this study. We report that even at low dose of Cd, it impaired the brain due to lipid peroxidase sensitivity which favoured the Cd-induced oxidative injury in the brain.

Correlation between cadmium and blood counts in workers exposed to urban stressor

The objective of this study was to assess the exposures to cadmium (Cd) in urban workers and the association between Cd exposure and values of blood counts. Urinary Cd, blood Cd, and blood counts were obtained from 355 outdoor workers; a subgroup of 99 subjects were monitored to evaluate personal exposure to airborne Cd. The mean value of personal exposure to Cd was 1.5 ng/m3 for traffic assistants and 1.2 ng/m3 for drivers. Urinary and blood Cd were correlated to the airborne Cd (respectively r=3 and r=4). The multiple linear regression models showed the associations among white blood cell, the percentage of neutrophils (NEU%), the percentage of lymphocytes (LYM%), and the concentrations of blood Cd (respectively R2=27, R2=37, R2=581). The subjects with blood Cd values higher than 1.2 μg/L showed an increase of LYM% mean values and a decrease of NEU% mean values with respect to the group with blood Cd values lower than 1.1 μg/L.

Tunisian radish (Raphanus sativus) extract prevents cadmium-induced immunotoxic and biochemical alterations in rats

Cadmium (Cd), a known carcinogen and potent immunotoxicant in humans and animals, is dispersed throughout the environment as a result of pollution from a variety of sources. Tunisian radish (Raphanus sativus) extract (TRE) is a known anti-oxidant and free radical scavenger that has been shown to help alleviate immune system disorders, including some induced by environmental toxicants. The present study was undertaken to investigate potential protective effects of TRE against Cd-induced immunotoxicities (and general toxicities) in situ. Cadmium chloride (at 2.5 mg CdCl2/kg BW) and TRE (5, 10, or 15 mg/kg BW) were given (alone or in combination [actually, in sequence of Cd and then TRE]) to rats daily by oral gavage for 2 weeks. Results indicated that treatment with CdCl2 alone resulted in significant decreases in plasma levels of total protein, triglycerides, creatine kinase, creatinine, IgG and IgA, T-lymphocyte sub-types (CD4(+), CD3(+), CD56(+), and CD8(+)), and in thymic and hepatic indices (relative weights). In contrast, CdCl2 treatment caused significant increases in serum LDH, AST, and ALT, in the formation/release of pro-inflammatory cytokines (IL-1 and TNFα), and in the relative weights of host spleen and kidneys. Rats treated with TRE alone had no discernable changes compared to the controls with regard to all test parameters. Combined treatment of CdCl2 and TRE-at any dose-resulted in a significant improvement of all test parameters compared to those seen with Cd alone. These results illustrated (and provided further support for a continuing belief in) the beneficial effects of TRE in reducing the harmful outcomes of commonly encountered toxicants (like Cd) on the immune system and on overall host health status.

Exposure to residual concentrations of elements from a remediated coal fly ash spill does not adversely influence stress and immune responses of nestling tree swallows

Anthropogenic activities often produce pollutants that can affect the physiology, growth and reproductive success of wildlife. Many metals and trace elements play important roles in physiological processes, and exposure to even moderately elevated concentrations of essential and non-essential elements could have subtle effects on physiology, particularly during development. We examined the effects of exposure to a number of elements from a coal fly ash spill that occurred in December 2008 and has since been remediated on the stress and immune responses of nestling tree swallows. We found that nestlings at the site of the spill had significantly greater blood concentrations of Cu, Hg, Se and Zn in 2011, but greater concentrations only of Se in 2012, in comparison to reference colonies. The concentrations of elements were below levels of significant toxicological concern in both years. In 2011, we found no relationship between exposure to elements associated with the spill and basal or stress-induced corticosterone concentrations in nestlings. In 2012, we found that Se exposure was not associated with cell-mediated immunity based on the response to phytohaemagglutinin injection. However, the bactericidal capacity of nestling plasma had a positive but weak association with blood Se concentrations, and this association was stronger at the spill site. Our results indicate that exposure to these low concentrations of elements had few effects on nestling endocrine and immune physiology. The long-term health consequences of low-level exposure to elements and of exposure to greater element concentrations in avian species require additional study.

Cadmium exposure induces hematuria in Korean adults

INTRODUCTION

Toxic heavy metals have adverse effects on human health. However, the risk of hematuria caused by heavy metal exposure has not been evaluated.

METHODS

Data from 4701 Korean adults were obtained in the Korean National Health and Nutritional Examination Survey (2008-2010). Blood levels of the toxic heavy metals cadmium, lead, and mercury were measured. Hematuria was defined as a result of ≥+1 on a urine dipstick test. The odds ratios (ORs) for hematuria were measured according to the blood heavy metal levels after adjusting for multiple variables.

RESULTS

Individuals with blood cadmium levels in the 3rd and 4th quartiles had a greater OR for hematuria than those in the 1st quartile group: 3rd quartile, 1.35 (1.019-1.777; P=0.037); 4th quartile, 1.52 (1.140-2.017; P=0.004). When blood cadmium was considered as a log-transformed continuous variable, the correlation between blood cadmium and hematuria was significant: OR, 1.97 (1.224-3.160; Ptrend=0.005). In contrast, no significant correlations between hematuria and blood lead or mercury were found in the multivariate analyses.

DISCUSSION

The present study shows that high cadmium exposure is associated with a risk of hematuria.

Preventive effect of phytoglycoprotein (27 kDa) on inflammatory factors at liver injury in cadmium chloride-exposed ICR mice

Cadmium is one of the inflammation-related xenobiotics and has been regarded as a potent carcinogen. Gardenia jasminoides Ellis (GJE) has been used to cure inflammation in Korean folk medicine for a long time. The purpose of present study is the inhibitory effect of glycoprotein isolated from GJE (27 kDa) on inflammation mechanism in cadmium chloride-exposed ICR mice. We evaluated the activities of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and thiobarbituric acid-reactive substances (TBARS), activities of anti-oxidative enzymes [superoxide dismutase (SOD) and gluthathione peroxidase (GPx)], activities of c-Jun N-terminal protein kinase (JNK), heat shock protein 27 (Hsp27), activator protein (AP)-1, nuclear factor (NF)-κB and expression of inflammation-related mediators including tumor necrosis factor (TNF)-α and interleukin (IL)-6 in cadmium chloride-exposed ICR mice using immunoblot analysis, EMSA and RT-PCR. It notes that mice plasma was used to measure ALT, LDH, and TBARS after treatment with cadmium chloride alone or cadmium chloride under the pretreatment with GJE glycoprotein. Liver tissues were used to assess activities of anti-oxidant enzymes, SAPK/JNK, Hsp27, AP-1, NF-κB, TNF-α, and IL-6 in this study. The results obtained from this study revealed that GJE glycoprotein (10 mg/kg) decreased the levels of LDH, ALT and TBARS, whereas increased the activity of hepatic anti-oxidant enzymes (SOD and GPx) in cadmium chloride-exposed ICR mice. Moreover, it decreased the activity of JNK/AP-1, NF-κB, Hsp27, and pro-inflammatory cytokines (TNF-α and IL-6). Taken together, the results in this study suggest that GJE glycoprotein inhibits the expression of inflammation-related cytokines (TNF-α and IL-6) in cadmium chloride-exposed ICR mice.

Cadmium ions promote monocytic differentiation of human leukemia HL-60 cells treated with 1α,25-dihydroxyvitamin D3

Cadmium exposure has multiple effects on the immune system. These can be stimulating, leading to improved clearance of infections, or inhibiting, increasing susceptibility toward infectious agents. Onein vivoobservation in cadmium-exposed individuals is increased monocyte numbers. Therefore, the objective of this study is to investigate the impact of cadmium on monocyte differentiation in the HL-60 model cell line. Administered alone, cadmium had no effect. However, cadmium amplified the expression of monocyte surface markers CD11b and CD14 when differentiation was induced by 1α,25-dihydroxyvitamin D3 (VD3). Furthermore, differentiation with VD3 in the presence of cadmium augmented key monocyte functions: the capacities to perform phagocytosis and generate an oxidative burst. One important signaling pathway required for monocyte differentiation involves extracellular signal-regulated kinase (ERK)1/2. Notably, cadmium induced ERK1/2 phosphorylation in HL-60 cells. Furthermore, U0126, which inhibits ERK1/2 phosphorylation by upstream MAPK/ERK kinases (MEK)1/2, reduced VD3-mediated differentiation and abrogated the effects of cadmium. In conclusion, cadmium can augment monocytic differentiation by activating ERK1/2 signaling, leading to increased generation of functional monocytes. These increased monocyte numbers could contribute to the impact of cadmium on the immune system owing to their role in the production of pro-inflammatory cytokines and activation of T-cells by antigen presentation.

Immunomodulatory role of piperine in cadmium induced thymic atrophy and splenomegaly in mice

Cadmium being a potent immunotoxicant, affects both humoral and cell mediated immunity. In rodents, it is primarily characterized by marked thymic atrophy and splenomegaly. Cadmium induces apoptosis in mice and suppresses the immune functions. Piperine, major alkaloid of Piper longum Linn. and Piper nigrum Linn. with a long history of medicinal value, has shown anti-apoptotic activity in vitro. Thus, to delineate its role in vivo, piperine (2.5mg/kg/day, oral, 7 days) treated Balb/C mice were administered Cd as CdCl(2) (1.8mg/kg, i.p., once, 4th day). The various biochemical indexes of cell damage such as cytotoxicity (MTT assay), oxidative stress (glutathione, reactive oxygen species), apoptosis (mitochondrial membrane potential, caspase-3 activity, phosphatidylserine externalization, apoptotic DNA, intranucleosomal DNA fragmentation) along with lymphocyte phenotyping, cell proliferative response and cytokine secretion (IL-2 and IFNγ) were assessed in thymic and splenic single cell suspensions. Lowering of body weight gain and cellularity and a loss in cell viability seen in Cd group, were abrogated by piperine treatment. Similarly, oxidative stress and apoptotic markers altered by Cd were also modulated by this alkaloid. In addition, a pronounced inhibition of cell proliferative response, alterations in T- and B-cell phenotypes, cytokine release and morphological changes were restored to normalcy. The present in vivo data corroborating with our previous in vitro findings, provide confirmatory evidence of the immuno-protective efficacy of piperine.

Impact of cadmium in T lymphocyte subsets and cytokine expression: differential regulation by oxidative stress and apoptosis

Cadmium (Cd), a possible human carcinogen is a potent immunotoxicant. In rodents it causes thymic atrophy and splenomegaly, in addition to immuno-suppression and modulation of humoral and/or cellular immune response. Oxidative stress and apoptosis appear to be underlying mechanism of Cd induced thymic injury. To understand the involvement of reactive oxygen species (ROS), intracellular glutathione (GSH) and apoptosis in modulation of T-cell repertoire, we studied the effect of Cd (10, 25 and 50 microM) on primary T lymphocytes of BALB/c mice at different time intervals (6, 12 and 18 h). We observed a dose and time dependent decline in CD4(+)/CD8(+) ratio (a bio-indicator of immunotoxicity) as a result of significant suppression of CD4(+)subsets (helper T-cells) and enhancement in CD8(+) cells (cytotoxic T-cells) At the same time, the CD4(+)CD8(+) (DP) cell population was lowered while the CD4(-)CD8(-) (DN) cells were increased. The oxidative stress and apoptotic data revealed almost similar ROS generation in both CD4(+) and CD8(+) cells, but relatively more marked GSH depletion and apoptosis in CD4(+) than in CD8(+) population. On further analysis of CD4(+) T-subsets, cytokine release (IL-2 and IFNgamma) by Th 1 cells and IL-4 by Th 2 cells were shown to be significantly suppressed in a dose responsive manner. The highest inhibition was observed in IFNgamma, then IL-2 followed by IL-4. In conclusion, our data demonstrates that T-cell apoptosis by Cd, more in CD4(+)than in CD8(+)cells appear related to higher depletion of intracellular glutathione. Th 1 cells of CD4(+) sub-population are more responsive to Cd than Th 2, leading to higher suppression of IL-2 and IFNgamma than IL-4 and hence, the study unravels to some extend, the underlying events involved in Cd immunotoxicity.

Role of oxidative stress and apoptosis in cadmium induced thymic atrophy and splenomegaly in mice

Cadmium immunotoxicity in rodents is primarily characterized by marked thymic damage and splenomegaly. To understand the toxicity of Cd on lymphoid cells in vivo, a single dose of Cd as CdCl2 (1.8 mg/kg, i.p.) was administered to male BALB/c mice and cytotoxicity (MTT assay), oxidative stress indicators (glutathione, reactive oxygen species) and apoptotic markers (mitochondrial membrane potential, caspase-3 activity, phosphatidylserine externalization, apoptotic DNA, intranucleosomal DNA fragmentation) were assessed in thymic and splenic single cell suspensions, at various time intervals. Lowering of body weight gain and cellularity and a loss in cell viability was seen in the Cd treated mice. The earliest significant increase in ROS at 18 h, followed by mitochondrial membrane depolarization, caspase-3 activation and GSH depletion at 24h in spleen and later at 48 h in thymus, strongly implicate the possible involvement of ROS. A pronounced inhibition of cell proliferative response at 48 h and 72 h may also be linked to Cd induced apoptosis. The morphological alterations including thymic cortical cell depletion and an increase in red pulp with diminished white pulp in spleen were observed at 48 h and beyond. The splenic cells appeared more susceptible than thymus cells to the adverse effects of Cd. The present study, therefore, demonstrates potentiation of oxidative stress followed by mitochondrial-caspase dependent apoptotic pathway. This may, in part, be responsible for causing suppression of cell proliferative response, thymic atrophy and splenomegaly.

Inactivation of cadmium induced immunotoxicological alterations in rats by Tunisian montmorillonite clay

Cadmium (Cd(2+)) is a heavy metal that is dispersed throughout the modern environment mainly as a result of pollution from a variety of sources. The aims of the current study were to investigate the efficacy of purified Tunisian montmorillonite clay (TMC) to adsorb Cd, to test the stability of the resulting complex under different conditions in vitro, and to utilize the rat bioassay as an in vivo model to evaluate the protective role of TMC against Cd-induced toxicity and immunodysfunction. In the in vitro study, three concentrations of TMC (0.5, 1.0 and 1.5 g/l aqueous solution) and three concentrations of CdCl(2) (25, 50 and 100 ppm) were tested. The results of the in vitro study showed that TMC had a high capacity of adsorbing Cd at different concentrations tested. The adsorption ranged from 95.7-100% of the available CdCl(2) in aqueous solutions. The complex TMC-Cd was stable at different pHs at 37 degrees C. The in vivo results indicated that treatment with CdCl(2) (2.5 mg/kg BW) for 2 weeks resulted in a significant decrease in triglycerides, total protein, creatinine, creatine kinase, immunoglobulin profile (Ig A and Ig G) and T-cell sub-types (CD3(+), CD4(+), CD8(+) and CD56(+)). Whereas, it significantly increase serum level of AST, ALT, LDH and induced degenerative changes in pro-inflammatory cytokines (TNF-alpha and IL-1). Rats treated with TMC alone (400, 600 and 800 mg/kg BW) were comparable to the control regarding all the tested parameters. The combined treatment of CdCl(2) and TMC at the lowest dose (400 mg/kg BW) showed a significant improvement of all tested parameters. It could be concluded that TMC was effective to protect against Cd hazards at a dose as low as 400 mg/kg BW. These results supported our hypothesis that TMC tightly-bind and immobilized Cd resulted in reduction of metal bioavailability in the gastrointestinal tract.

Modulation of cadmium induced alterations in murine thymocytes by piperine: oxidative stress, apoptosis, phenotyping and blastogenesis

Piperine, a main component of Piper longum Linn. and Piper nigrum Linn., is a plant alkaloid with a long history of medicinal use in Indian medicine. It is known to exhibit a variety of biological activities which include anti-pyretic, anti-inflammatory, anti-depressant, hepatoprotective and antitumor. Its immunomodulatory role has so far been limited to humoral response. The influence of piperine on murine thymocytes, immunocompromised by cadmium has been reported by us in this investigation. The various biochemical parameters such as oxidative stress markers (ROS and GSH), Bcl-2 protein expression, mitochondrial membrane potential, caspase-3 activity, DNA damage, blastogenesis and T lymphocyte phenotypes were determined. Cadmium (25 microM) induced apoptosis earliest at 6 h. Alterations in ROS and GSH preceded mitochondrial membrane depolarization and caspase-3 activation followed by apoptosis. The phenotypic changes occurred at 18 h and blastogenesis at 72 h. Various conc. of piperine (1, 10 and 50 microg/ml) when added along with Cd (25 microM) from 1.5 to 72 h, caused a dose and time dependent amelioration in all the cellular events mentioned above. Modulation of oxidative stress has earlier been reported to reduce Cd induced apoptosis in murine lymphocytes. Inhibition of the ROS production and replenishment of GSH by piperine, may in part be responsible for the suppression of downstream cascade of events, i.e. apoptosis, blastogenesis and T lymphocyte phenotyping. The study clearly demonstrated the anti-oxidative, anti-apoptotic, and restorative ability against cell proliferative mitogenic response and phenotypic alterations by piperine, suggesting its therapeutic usefulness in immunocompromised conditions.

The in vitro immune modulation by cadmium depends on the way of cell activation

Among environmental contaminants known for their toxicity and worldwide distribution, heavy metals are of primary concern. Although the toxicology of cadmium (Cd) has been extensively studied, little information is available on the immunomodulation driven by exposure to low doses of Cd. We aimed to evaluate the immunomodulatory effects elicited by short-term exposure of human immunocompetent cells to low biologically relevant doses of Cd in two activation models. Human peripheral blood mononuclear cells, activated either by bacterial antigens (heat-killed Salmonella Enteritidis) or monoclonal antibodies (mAb: anti-CD3/anti-CD28/anti-CD40), were exposed to Cd acetate for 24h. Cell vitality was determined by MTT assay, cytokine release by ELISA, and cytokine gene expression by real-time RT-PCR. The results demonstrated that, in addition to the known toxic effects of Cd, doses from 0.013 to 13.3 microM exert differential effects on cytokine production. In the case of mAb-activation, secretion of interleukin (IL)-1 beta, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma was greatly inhibited at low Cd doses compared to production of IL-4 and IL-10. This indicates a type-2-biased immune response. Under stimulation by bacterial antigens, release of IL-10 was highly suppressed compared to that of IFN-gamma and TNF-alpha; IL-4 was undetectable. These results imply that low Cd doses exert immunomodulatory effects and the direction of this modulation depends on the pathway to cell activation. Overall, Cd polarizes the immune response toward type-2 in cells stimulated via T cell receptors. However, a polarized type-1 response induced by bacterial antigens could not be overwhelmed by the effects of Cd.

Oxidative stress and apoptotic changes in murine splenocytes exposed to cadmium

Cadmium being a potent immunotoxicant, affects both humoral and cell mediated immunity. However, its effect on spleen is not clearly understood. Hence, to delineate the action of Cd, mouse splenic lymphocytes were exposed to Cd (10, 25 and 50 microM) for 60 min, 1.5, 3, 6 and 18 h. At 6 h, apoptosis was reflected by DNA fragmentation, increased sub-G1 population (apoptotic DNA) and apoptotic cells (Annexin V binding assay). The early stage markers of apoptosis, i.e. decreased mitochondrial membrane potential and caspase-3 activation were observed as early as 1.5 h by the highest dose of Cd (50 microM). Significant ROS production by 25 and 50 microM Cd at 60 min occurred prior to the lowering of mitochondrial membrane potential, suggesting involvement of ROS in causing mitochondrial membrane damage. N-acetylcysteine and pyrrolidine dithiocarbamate (thiol antioxidants) lowered the sub-G(1) population, inhibited the ROS generation and raised the GSH levels induced by Cd. Buthionine sulfoximine (GSH depletor) on the other hand, enhanced the ROS production as well as the sub-G1 fraction. These results imply that ROS is a critical mediator of Cd-induced apoptosis and that cadmium may compromise splenic immune function by accelerating apoptosis.

Immune Modulation by Cadmium and Lead in the Acute Reporter Antigen–Popliteal Lymph Node Assay

Immune modulation by heavy metals may cause serious adverse health effects in humans, although the mechanisms involved are not well understood. Both cadmium and lead are important environmental and occupational toxins. Therefore, in the current study, the costimulatory/adjuvant effects and the T-cell-activating potential of these metals (i.e., CdCl2 and PbCl2), are examined. These immune-modulating properties are critical in the development of conditions such as allergy, hypersensitivity, and autoimmunity. Using the direct popliteal lymph node assay (PLNA) and reporter antigen-popliteal lymph node assay (RA-PLNA) both metals were examined individually for immunotoxicity. Mercury (i.e., HgCl2) was included for comparative purposes as its effects in the RA-PLNA are well documented. Seven days following a single footpad injection containing metal and/or RA (trinitrophenyl-ovalbumin [TNP-OVA] or TNP-Ficoll), BALB/c mice were sacrificed and the popliteal lymph nodes (PLNs) removed. PLN cellularity, TNP-specific antibody-secreting cells (ASCs), and lymphocyte subsets were assessed. All three metals strongly stimulated T- and B-cell proliferation and ASC production following coinjection with the RA TNP-OVA. In each case, ASC production was skewed towards the IgG1 isotype. In addition, all three metals induced IgG production to TNP-Ficoll (although relatively weakly in the case of Cd). These results show that each of these metals can provide adjuvant signals to promote lymphocyte proliferation and enhance adaptive immune responses to unrelated antigens. Skewing of immune responses towards T helper type 2 responses suggests that each of these metals can enhance allergic and hypersensitivity reactions to environmental antigens. Furthermore, the induction of IgG responses to TNP-Ficoll, a T-cell-independent antigen, indicates that each of these metals can activate neoantigen-specific T cells. T-cell activation by metals can lead to metal hypersensitivity and has been implicated in the development of autoimmunity. This is the first report of immune modulation by CdCl2 and PbCl2 in the RA-PLNA.

Toxicity of cadmium in Japanese quail: evaluation of body weight, hepatic and renal function, and cellular immune response

Cadmium (Cd) is an environmental pollutant that is able to alter the immune function. Previous studies have shown that, in mammals, chronic exposure to Cd decreases the release of macrophagic cytokines such as IL1 and TN alpha and decreases phagocytosis activity. On the other hand contradictory results showed an increase in the humoral response. The cellular response could be decreased by exposure to Cd. These alterations were observed in mammals. The present study aimed to investigate some of the toxic effects of Cd exposure in birds. In particular, the main objective of this work was to elucidate the effects of exposure to this pollutant on the cellular immune function of the Japanese quail as a model for the study of toxicity in animals exposed in nature. The animals were exposed to the metal (100 ppm, per os) during development, i.e., from 1 to 28 days old. Body weight, biochemical parameters, and cellular immune response were measured during and at the end of treatment. The results showed that the exposure to Cd for 28 days significantly reduced the body weight and induced hepatic toxicity. The kidney function and cellular immune response were not affected by the Cd exposure.

Sex-specific effects of neonatal exposures to low levels of cadmium through maternal milk on development and immune functions of juvenile and adult rats

Cadmium (Cd) is a major environmental contaminant. Although immunotoxic effects have been associated with Cd exposure, the inconsistency of experimental results underlines the need of an experimental approach more closely related to environmental conditions. We investigated the effects of exposing neonatal Sprague-Dawley rats to environmentally relevant doses of Cd through maternal milk. Dams received 10 parts per billion (ppb) or 5 parts per million (ppm) Cd chloride (CdCl2) in drinking water from parturition until the weaning of the pups. Half of the offspring was sampled at weaning time. The remaining juvenile rats received water without addition of Cd until adulthood. Cd accumulation in kidneys of juvenile rats fed from dams exposed to Cd indicated the transfer of the metal from mother to pups through maternal milk. This neonatal exposure resulted in decreased body, kidney and spleen weights of just weaned females but not of males. This effect was more pronounced in the less exposed females fed from dams exposed to 10 ppb Cd, which also displayed lower hepatic metallothionein-1 (MT-1) mRNA levels. The effect of Cd exposure on body and organ weights did not persist to adulthood. In contrast, we observed gender-specific effects of neonatal Cd exposure on the cytotoxic activity of splenic NK-cells of both juvenile and adult rats. Cd also strongly inhibited the proliferative response of Con A-stimulated thymocytes in both male and female adult rats 5 weeks after the cessation of Cd exposure. These immunotoxic effects were observed at doses much lower than those reported to produce similar effects when exposure occurred during adulthood. In conclusion, neonatal exposures to environmentally relevant levels of Cd through maternal milk represent a critical hazard liable to lead to both transitory and persistent immunotoxic effects.

Effect of cadmium on lymphocyte subsets distribution in thymus and spleen

This work was designed to analyze the possible dose dependent effects of cadmium on the distribution of lymphocyte subsets within the thymus and spleen. Cadmium accumulation was also evaluated in these tissues. For this purpose, adult male rats were exposed for one month to 0, 5, 10, 25, 50 or 100 ppm of cadmium chloride (CdCl2) in the drinking water. In both spleen and thymus, the B lymphocytes increased with the doses of 5 and 10 ppm of CdCl2, and decreased with the doses of 25-100 ppm. In spleen, the doses of 25 and 50 ppm decreased CD4+ cells and the doses of 5 and 10 ppm increased CD8+ cells, while the percentage of thymus T, CD4+, CD8+ and CD4(+)-CD8+ cells was not modified by cadmium treatment at any dose used in this study. After cadmium exposure, the metal was accumulated in the spleen only from the dose of 50 ppm on, and in the thymus, from the dose of 10 ppm on. In conclusion, although the accumulation of the metal is higher in thymus than in spleen, the metal affected CD4+ and CD8+ lymphocytes at the spleen but not at the thymus.

Immune function, stress response, and body condition in arctic-breeding common eiders in relation to cadmium, mercury, and selenium concentrations

We examined relationships between trace metal concentrations in tissues of common eider ducks (cadmium, mercury, and selenium) and selected biomarkers of health (stress response, immune function, and body condition). This study was conducted at an eider nesting colony in the Canadian arctic in 1998 and 1999. Capture-induced stress, measured as the rise in corticosterone concentrations following capture, was positively related (P=0.03) to renal cadmium concentration in 1998 when incubating eiders were sampled, but not in 1999 when prenesting eiders were sampled. Stress response was inversely related (P=0.02) to selenium concentrations in 1999. Following capture and blood sampling in 1999, eiders were placed in a flight pen on-site for eight days in order to examine immune function. Cell-mediated immunity, measured as the skin-swelling response to an intradermal injection of phytohemagglutinin-P, (PHA-P), was positively related (P=0.003) to hepatic selenium. The heterophil:lymphocyte ratio was inversely related (P=0.08) to hepatic selenium. In 1998, selenium was positively related to body mass (P=0.01), abdominal fat mass (P=0.07), kidney mass (P=0.03), and liver mass (P=0.07). In 1999, hepatic mercury was negatively related to abdominal fat mass (P=0.01), spleen mass (P=0.07) and body mass at capture (P=0.09) in prenesting eiders.

Effects of cadmium and vanadium ions on antigen-induced signaling in CD4(+) T cells

Heavy metal environmental pollutants modulate antigen-directed responses by T lymphocytes, but the molecular mechanisms by which certain metal ions exert their effects are only poorly understood. We tested the hypothesis that cadmium and vanadium ions alter antigen-induced T cell signal transduction pathways in CD4(+) T helper cells. We used CD4(+) primary T lymphocytes and splenic T cells from DO.11.10 T cell receptor transgenic mice. We determined the effects of cadmium chloride and sodium orthovanadate at concentrations that did not induce apoptotic cell death, but affected cytokine or proliferation responses to antigenic stimulation. We used electrophoretic mobility shift assays to measure effects of cadmium and vanadium ions on antigen-induced activation of the nuclear transcriptional regulator proteins, nuclear factor-kappaB, cyclic AMP response element binding protein, nuclear factor of activated T cells, and activator protein-1. Different signaling pathways lead to activation of these transcription factors. Our results suggest that the two heavy metal ions differentially affect signaling pathways. This knowledge will help in the development of molecular epidemiological assays.