Community health perceptions and human environmental exposure to chromium contamination in a small New Jersey City.

Following a 1983 chromic acid (hexavalent chromium [CrVI]) spill from a Garfield, NJ electroplating plant, CrVI-contaminated water was found in a local firehouse basement in 1993. An ATSDR public health advisory was issued for the plant site in 2010, and from 2008-2015, fourteen residential properties have required remediation to address CrVI-contaminated dust in the basements. As part of the Community Outreach and Engagement Core of the NYU NIEHS Center, seventytwo Garfield residents aged 18-65 years, participated in a community survey with the goal of identifying concerns related to environmental and community health. Thirty-two percent responded that they 'didn't know' if they were exposed to chemicals or pollutants where they live. This finding suggests a limited awareness of environmental chemical exposures, chromium contamination and/or potential exposure to CrVI. Furthermore, toenail clippings were collected from forty-seven Garfield residents and analyzed for total chromium levels to assess potential long-term exposure. On average, residents living on/inside the contaminated plume area had higher total chromium levels in their toenail clippings than residents living outside the plume area. However, chromium levels for all participants were within the range of historical normal. This study highlights the value of partnerships between environmentally-impacted community's and academic scientists working together to identify potential contaminant exposures and address public health concerns through research and environmental health education.

Early life insult from cigarette smoke may be predictive of chronic diseases later in life.

Evidence is rapidly accumulating that links cigarette smoke (CS) exposure in utero with the development of a variety of disease pathologies in the older offspring including, type 2 diabetes, obesity, certain childhood cancers and respiratory disorders. The role that the fetal environment plays in these late-onset outcomes and the underlying cellular/molecular mechanisms by which these CS-induced effects may occur are currently unknown. Although we are becoming more aware of the fact that prenatal insult can underlie childhood/adult diseases, critical knowledge gaps still exist including gene-environment interactions, and how a CS-induced imbalance in immune dynamics (i.e. TH1/TH2) might affect asthma development and/or exacerbation later in life. In this mini-review we introduce the concept of sexual dimorphism in CS-induced late-onset disease outcomes, as well as explore the mechanisms by which CS exposure in utero can lead to cardiovascular, cancer and respiratory abnormalities in the exposed offspring. By addressing such questions using animal models, appropriate intervention strategies can be developed that will help to protect children's health and their long-term quality of life.

Relationship between serotonin and the immune system in a teleost model.

An immunomodulatory role for serotonin (5-HT) has been demonstrated in mammals and evidence for a similar role for 5-HT has recently emerged in fish. However, as limited studies are available, discrepancies often exist regarding the role of 5-HT in the teleost immune response. Therefore, studies were undertaken to help clarify this relationship. Lymphocyte proliferation and extracellular superoxide (O2.-) production were examined in cells from bluegill sunfish injected with either 5-HTP (the immediate precursor to 5-HT) or pCPA (an inhibitor of the rate-limiting enzyme in 5-HT synthesis), or, in vitro following exposure of immune cells to either 5-HT, the 5-HT(1A) receptor agonist, 8-OH-DPAT, or the receptor antagonist, NAN-190. Exposure of fish to 5-HTP increased whole brain 5-HT levels, while pCPA exposure decreased whole brain and splenic 5-HT. In vivo exposure of fish to pCPA depressed T- and B-lymphocyte proliferation; exposure to 5-HTP failed to alter either immune endpoint. In vitro exposure of bluegill splenocytes to 5-HT or 8-OH-DPAT inhibited lymphoproliferation; treatment with NAN-190 had no effect on immune function. Results suggest a link in bluegill between immune function and the serotonergic system. The disparity observed following in vivo- and in vitro-induced serotonergic alterations indicates the complexity of this neuro-immune relationship and emphasizes the need for further studies in this regard.

Detection of changes in alveolar macrophage iron status induced by select PM2.5-associated components using iron-response protein binding activity.

The extent of adverse health effects, including induction/exacerbation of infectious lung disease, arising from entrainment of equivalent amounts (or exposure to a fixed increment) of fine particulate matter (PM2.5) can vary from region to region or city to city in a region. To begin to explain how differing effects on host resistance might arise after exposure to PM2.5 from various sites, we hypothesized that select metals (e.g., V, Al, and Mn) in each PM2.5 caused changes in alveolar macrophage (AM) Fe status that, ultimately, would lead to altered antibacterial function. To test this, iron-response protein (IRP) binding activity in a rat AM cell line was assessed after exposure to Fe alone and in conjunction with V, Mn, and/or Al at ratios of V:Fe, Al:Fe, or Mn:Fe encountered in PM2.5 samples from New York City, Los Angeles, and Seattle. Results indicated that V and Al each significantly altered IRP activity, though effects were not consistently ratio-(i.e., dose-) dependent; Mn had little impact on activity. We conclude that the reductions in Fe status detected here via the IRP assay arose, in part, from effects on transferrin-mediated Fe3+ delivery to the AM. Ongoing studies using this assay are allowing us to better determine: (1) whether mass (and/or molar) relationships between Fe and V, Al, and/or Mn in any PM2.5 sample consistently govern the extent of change in AM Fe status; (2) how much any specified PM2.5 constituent (metal or nonmetal) contributes to the overall disruption of Fe status found induced by an intact parent sample; and (3) whether induced changes in binding activity are relatable to other changes expected to occur in the AM, that is, in IRP-dependent mRNA/levels of ferritin/transferrin receptor and Fe-dependent functions. These studies demonstrate that pollutant-induced effects on lung cell Fe status can be assessed in a reproducible manner using an assay that can be readily performed by investigators who might otherwise have no access to other very costly analytical equipment, such as graphite atomic absorption or x-ray fluorescence spectro(photo)meters.

Effects of elevated temperature and nickel pollution on the immune status of Japanese medaka.

Changes in a host's environment (i.e. physical or chemical) can alter normal immune function. In aquatic organisms, exposure to stress can result in significant changes in innate immunity. In the natural environment, fish are exposed to multiple stressors simultaneously. Temperature change and/or chemical exposure as individual environmental stressors have been shown in various fish species to alter all aspects of the immune response. These same stressors have also been shown to alter plasma steroid levels in exposed fish. For this study, the effects of elevated temperature and nickel pollution on specific immune parameters of Japanese medaka (Oryzias latipes) were determined. Fish were exposed for 1, 7 or 14d to either: waterborne nickel (Ni) at the nominal concentration of 125ppb; a 5 degrees C (+/-0.5 degrees C) rapid increase in water temperature; or, both potential stressors in combination. Medaka maintained at room temperature (25 degrees C+/-1 degrees C) served as the controls. Altered function of the innate and adaptive arms of the immune response was evaluated by assessing kidney macrophage-mediated superoxide (O(2)(-)) production and splenic T-cell proliferation, respectively. Plasma cortisol levels were analysed in the same fish as a marker of the physiological stress response. While kidney cell number was unaffected by exposure of fish to either stressor alone or both factors in combination, spleen cellularity was decreased (compared to control fish) in medaka exposed for 1d to thermal stress in combination with Ni, and to a lesser extent to thermal stress alone. T-lymphocyte proliferation by medaka splenocytes was not affected by any exposure paradigm. Unstimulated intracellular O(2)(-) production by kidney phagocytes was significantly elevated (compared to control) in medaka exposed for 1d to either thermal stress alone or temperature change in combination with Ni; by 7d, only the stressor combination significantly increased baseline O(2)(-) production. Resting levels of extracellular O(2)(-) production was significantly reduced in fish maintained for 1d at the elevated temperature. Effects on phorbol 12-myristate 13 acetate (PMA)-stimulated intracellular and extracellular O(2)(-) production were less dramatic than those observed for resting phagocytes. Exposure of medaka to elevated temperature for 14d tended (p<0.06) to reduce PMA-stimulated intracellular O(2)(-) production (compared to the time-matched control). Although exposure of fish for 14d to elevated temperature only slightly reduced stimulated extracellular O(2)(-) production, exposure for the same duration to Ni alone significantly depressed oxyradical production by kidney phagocytes (compared to the time-matched controls). Decreased plasma cortisol levels were observed in fish exposed for 7d to either an elevated water temperature or Ni (compared to the time-matched control); by 14d of exposure, no significant treatment-induced effects on cortisol levels were observed. These findings add to the growing body of literature seeking to determine what effects, if any, exposure to multiple aquatic pollution-induced effects have upon fish health and the health of impacted ecosystems.

Benzo[a]pyrene-induced immunotoxicity in Japanese medaka (Oryzias latipes): relationship between lymphoid CYP1A activity and humoral immune suppression.

Exposure to the environmental contaminant benzo[a]pyrene (BaP) results in suppression of immune function in both mammalian and fish species. This laboratory has previously demonstrated that a single intraperitoneal (IP) injection of BaP reduced lymphocyte proliferation, phagocyte-mediated superoxide generation, and antibody-forming cell (AFC) numbers in Japanese medaka (Oryzias latipes). The objective of the current study was to determine the role of BaP metabolism in the observed immunosuppression. Results from rodent studies have suggested that BaP elicits its immunotoxic effects via upregulation of cytochrome P4501A1 (CYP1A1) and the subsequent production of immunosuppressive BaP metabolites. In this study, exposure of medaka to 200 microg BaP/g BW significantly induced CYP1A expression or activity within lymphoid tissue 48 h post-IP injection; induction was observed specifically within distinct subpopulations of kidney mononuclear cells. Concurrent injection of fish with BaP and the CYP1A1 inhibitors alpha-naphthoflavone (ANF) or dehydroepiandrosterone (DHEA) resulted in inhibition of renal EROD activity and amelioration of BaP-induced suppression of medaka AFC numbers. Results of this study suggest that (1) BaP-induced suppression of medaka humoral immunity relies upon the CYP1A-catalyzed production of immunotoxic BaP metabolites and (2) BaP metabolites may be created in situ, directly by specific cells within kidney lymphoid tissue. Thus, apparently, mechanisms involved in BaP-induced immunosuppression have been phylogenetically conserved from fish to mammals.

Suppressive effects of benzo[a]pyrene upon fish immune function: evolutionarily conserved cellular mechanisms of immunotoxicity.

Knowledge gained through the use of alternative animal models has significantly enhanced our understanding of life at all levels of biological organization. The discipline of toxicology is under considerable pressure to develop such models due to increasing public concern regarding the experimental use of mammals. Studies in this laboratory have focused on the utility of a small laboratory fish model, the Japanese medaka (Oryzias latipes), to investigate immunotoxicological effects of benzo[a]pyrene (BaP). BaP is a ubiquitous environmental contaminant and known mammalian immunotoxicant. This laboratory has demonstrated that in vivo exposure of medaka to BaP (2-200 microg/g BW) significantly depresses both innate and humoral immunity. Further studies have indicated that BaP activates its own biotransformation pathway within medaka immune cells following both in vivo and in vitro exposure. In addition, reduction of BaP metabolism with alpha-naphthoflavone results in the reversal of BaP-induced suppression of antibody production in vitro. Inhibition of CYPlA-mediated metabolism within medaka immune cells also alleviates the immunotoxicity induced by benzo[a]pyrene-7,8-dihydrodiol, but not benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE). This suggests that BPDE may be an ultimate immunotoxicant. Results from this study in medaka are in agreement with previously conducted rodent studies that indicated a role for immunotoxic BaP metabolites in BaP-induced suppression of humoral immunity.

Biochemical and toxicopathic biomarkers assessed in smallmouth bass recovered from a polychlorinated biphenyl-contaminated river.

Smallmouth bass (Micropterus dolomieu) were collected to quantify the nature and prevalence of biomarker responses, including biochemical indices, toxicopathic lesions and general health indices, among fish collected from polychlorinated biphenyl (PCB)-contaminated and nearby uncontaminated reaches of the Kalamazoo River, Michigan, USA. Blood and tissue samples (gill, liver, spleen, head kidney, trunk kidney, thyroid and gonads) were collected and preserved at necropsy for biochemical and histological analyses. The body condition factor and liver somatic index were significantly lower in fish collected from the downstream, contaminated site. Plasma vitellogenin was not detected in male fish collected from either site. Liver ethoxyresorufin-O-deethylase activity and liver and spleen superoxide dismutase activity were significantly depressed in fish collected from the downstream site. Significant toxicopathic lesions such as glycogen depletion, enhanced macrophage aggregates, hepatic foci of cellular alteration (i.e. preneoplastic lesions) and neoplasia were also detected in the liver of fish collected from the downstream site. This study indicates that many of the biochemical and histopathological biomarker responses were associated with liver and body tissue PCB concentrations. Taken together, the biomarkers of exposure and effect strongly suggest that fish within the downstream site are adversely affected by PCBs and other chemical stressors.

Impact of polychlorinated biphenyls (PCBs) on the immune function of fish: age as a variable in determining adverse outcome.

Polychlorinated biphenyls (PCBs) are a major contaminant of global extent in water resources and aquatic biota. Due to its high lipid solubility, PCBs fail to be degraded and, therefore, continue to bioaccumulate throughout the environment and food chain. To determine the impact of PCBs on the immune system of aged and juvenile Japanese medaka (Oryzias latipes), fish were injected with the coplanar PCB congener 126 and examined after 3 and 14 days. PCB 126 produced oxidative stress in both age groups of fish 14 days post-injection; however, juvenile medaka appeared more susceptible than aged fish. Humoral immunity, as determined by antibody forming cell (AFC) numbers, was significantly depressed for up to 14 days post-injection in both age groups. These results demonstrate the sensitivity of the fish immune response for predicting PCB-induced immunotoxicity and identify age as a variable in determining adverse outcome.

The Japanese medaka (Oryzias latipes) model: applicability for investigating the immunosuppressive effects of the aquatic pollutant benzo[a]pyrene (BaP).

Despite the fact that BaP is a carcinogen, mammalian immunosuppressant, and ubiquitous aquatic pollutant, knowledge regarding the effects of BaP on the immune system of fish is still lacking. To begin to fill this gap, studies were conducted in medaka to examine the effects and mechanisms by which BaP exposure might alter host immunocompetence. Fish, exposed by IP injection of BaP (2-600 microg/g BW), were examined after 48 h for effects upon immune function and CYP1A expression/activity. Benzo[a]pyrene, at a concentration below that which increased levels of CYPIA expression/activity (2 microg BaP/g BW) suppressed lymphocyte proliferation. Concentrations of BaP at 20 and 200 microg/g BW. suppressed antibody-forming cell (AFC) numbers, superoxide production, and host resistance against bacteria. In contrast, exposure to the low affinity aryl hydrocarbon receptor (AhR) agonist, benzo[e]pyrene (BeP), neither induced CYP1A expression nor altered immune function. Given the lack of immunosuppressive effects produced by BeP, and the fact that exposure to the AhR antagonist (and CYP1A inhibitor) alpha-naphthoflavone (ANF) ameliorated the suppressive effects of BaP upon AFC numbers, the AhR pathway (including CYP1A-mediated production of reactive BaP metabolites) appears important in mediating BaP-induced immunotoxicity in fish, as in mammals. In the past, the medaka has proven a successful model for assessing carcinogenic agents. These studies have demonstrated its utility for also determining the immunosuppressive effects of an important aquatic contaminant.

Exposure of Japanese medaka (Oryzias latipes) to benzo[a]pyrene suppresses immune function and host resistance against bacterial challenge.

Besides being a potent chemical carcinogen, benzo[a]pyrene (BaP) has also been shown to suppress the immune response of mammals. However, even though BaP is a ubiquitous environmental contaminant to which aquatic species may be directly exposed, information regarding the effects of BaP on the immune system of fish is still lacking. Therefore, laboratory studies were conducted using Japanese medaka (Oryzias latipes) to examine the effects of BaP on host immune status. A single IP injection of BaP at 2, 20 or 200 microg/g BW had no effect upon medaka survival or condition factors for up to 7 days post-injection. Forty-eight hours after injection of either BaP or the vehicle control, fish were sacrificed and the appropriate organs/cells used to assess effects upon: splenic lymphocyte proliferation; kidney phagocyte intracellular superoxide (*O(2)(-)) production; and, CYP1A protein level/activity. In separate experiments, fish were injected with either sheep red blood cells or the bacterial pathogen Yersinia ruckeri at 48 h post-BaP exposure for later determination of antibody-forming cell (AFC) numbers and bacterial host resistance, respectively. Results demonstrated that in the absence of effects upon host survival or condition factors, a single exposure to a relatively low dose of BaP (2 microg/g BW) significantly suppressed mitogen-stimulated T- and B-lymphocyte proliferation (in the absence of elevated hepatic CYP1A expression/activity). At higher concentrations, BaP also reduced AFC numbers, phagocyte-mediated *O(2)(-) production, and host resistance against bacterial infection. These results clearly demonstrate the ability of BaP to compromise the immune response of fish and indicate the utility of the fish immune response to serve as an early indicator of BaP exposure/effects in exposed feral populations.

Toxicology and immunotoxicology of mercury: a comparative review in fish and humans.

This review addresses an important area of environmental and mammalian toxicology by evaluating and comparing mercury-induced effects upon the immune responses of two evolutionarily divergent yet immunologically-related species. The mechanisms of mercury toxicology and immunotoxicology are described herein, including supporting data from the following: sources of exposure; bioavailability and biodistribution; metabolism; and laboratory and field investigations. Based upon the studies presented, the relative sensitivities of fish and human immune cells to mercury exposure are compared and contrasted with regard to mercury's ability to stimulate and/or suppress host immunocompetence. In addition, results from immune assays are compared to mercury tissue burdens, as well as to toxicological threshold level estimates. Such comparisons may help to resolve gaps in our knowledge regarding sensitivity of immunological assays, standardization of immunotoxicological techniques between species, and the extent to which the vertebrate immune system possesses functional reserve and redundancy in response to xenobiotics. A review of this type begins to provide support for the potential usefulness of fish immune cells to serve as indicators for human immunotoxicology risk assessment. Analysis of the reviewed studies supports the following conclusions in both lower and higher vertebrates: a threshold for mercury-induced immunotoxicological effects is likely; multiple exposure scenarios involving high and/or chronic exposures leading to increased body burdens are linked to increased risk of immunomodulation; and highly exposed and/or susceptible subpopulations are at greater risk of toxicological impact.

Ozone-induced modulation of cell-mediated immune responses in the lungs.

Most pulmonary immunotoxicology studies of ambient pollutants have been broadly designed to discern if overall humoral or cell-mediated immunity (CMI) was altered; few have assessed effects on particular aspects of immune function. We hypothesized that effects from ozone (O3) exposure on pulmonary CMI are linked in part to changes in local immune cell capacities to form and/or to interact with immunoregulatory cytokines. Rats exposed to 0.1 or 0.3 ppm O3 4 h/day 5 days/week, for 1 or 3 weeks were assessed for resistance to, and pulmonary clearance of, a subsequent Listeria monocytogenes challenge. In situ cytokine release and immune cell profiles were also analyzed at different stages of the antilisterial response. Although O3 exposure modulated CMI, effects were not consistently concentration- or duration-dependent. Exposure did not effect cumulative mortality from infection, but induced concentration-related effects upon morbidity onset and persistence. All 1-week exposed rats had listeric burdens trending higher than controls; 0.3 ppm rats displayed continual burden increases rather than any onset of resolution. Rats exposed for 3 weeks had no O3-related changes in clearance. No exposure-related effect on neutrophil or pulmonary macrophage (PAM) numbers or percentages was noted. Bacterial burden analyses with respect to cell type showed that Listeria:PAM ratios in 0.3 ppm rats ultimately became greatest compared to all other rats. In situ IL-1alpha and TNFalpha levels were consistently higher in O3-exposed rats. All rats displayed increasing in situ IFNgamma levels as infection progressed, but no constant relationship was evident between IFNgamma and initial IL-1alpha/TNFalpha levels in O3-exposed hosts. It seems that short-term (i.e., 1 week) repeated O3 exposures imparted more effects upon CMI than a more prolonged (i.e., 3 week) regimen, with effects manifesting at the level of the PAM and in the cytokine network responsible for immunoactivation.

Biomarkers of immunotoxicity in fish: from the lab to the ocean.

Historically, host immunocompetence has been monitored using a battery of immune parameters. Recently, many of these same assays have been employed as biomarkers for predicting chemical-induced immunotoxicity in wildlife species. In this laboratory, assays measuring immunopathology, immune cell function, and host resistance against bacteria have been used successfully to assess immunotoxicity in laboratory-reared Japanese medaka (Oryzias latipes) and in feral fish populations. As an example of the latter, smallmouth bass collected from a PCB-contaminated site demonstrated significantly reduced phagocyte function and antioxidant activity compared to reference site fish. Taken together, these studies along with those from other investigators demonstrate the usefulness of immune assays as indicators to predict the toxicological risk associated with 'real-world' polluted aquatic environments.

Mammalian immunoassays for predicting the toxicity of malathion in a laboratory fish model.

This study describes the use of a panel of immune assays, originally developed by the National Toxicology Program for assessing xenobiotic-induced immunotoxicity in mice, to quantify the effects of sublethal malathion exposure on the immune responses of fish. For this study, Japanese medaka (Oryzias latipes) were exposed subchronically to the organophosphate pesticide malathion in a series of two experiments. In the first set of studies, fish were exposed for 7 or 14 d to untreated well water (i.e., controls) or to waterborne malathion at 0.2 or 0.8 mg/L. Following exposure, fish from each group were sacrificed and their kidneys (primary organ of leukopoiesis in fish and equivalent to mammalian bone marrow) were used to provide cells for assessing any malathion-induced effects upon nonspecific and acquired immune defense mechanisms. Effects upon humoral-mediated immunity were determined by enumerating antibody plaque-forming cell (PFC) numbers from a subset of fish exposed to malathion for 14 d and then injected intraperitoneally (ip) with sheep erythrocytes (sRBC). Results of these studies demonstrated that while malathion exposure had no significant effect upon hematocrit/leukocrit values or upon mitogen-stimulated T-cell lymphoproliferation, PFC numbers in the kidney of exposed fish were significantly reduced (compared to control fish) in a dose-dependent manner. In addition, total recoverable kidney cell numbers and viability, as well as superoxide anion production by kidney phagocytes, were reduced slightly (compared to control values) in fish exposed for 14 d to the highest malathion concentration tested. In the second set of experiments, medaka exposed for up to 21 d to either 0.1 or 0.3 mg malathion/L were challenged ip with an LD50 dose of the bacterial fish pathogen Yersinia ruckeri. Results from these infectivity studies demonstrated that exposure to either malathion concentration, for 14 or 21 d reduced host resistance against Yersinia infection. Taken together, these findings demonstrate the applicability of mammalian immune assays for predicting malathion-induced immunosuppression in a teleost fish, as well as the potential utility of a small laboratory fish to serve as an alternate model for mammals in immunotoxicological studies.

Immunotoxicologic effects of inhaled chromium: role of particle solubility and co-exposure to ozone.

Soluble and insoluble hexavalent chromium (Cr6+) agents are concomitantly released with ozone (O3) during welding. Although pulmonary/immunologic implications from exposure to each agent individually have been investigated, the effects from simultaneous exposure, as occurs under actual working conditions, are unclear. To investigate immunomodulatory effects of inhaled Cr6+, F-344 rats were exposed for 5 h/day, 5 days/week for 2 or 4 weeks to atmospheres containing soluble potassium chromate (K2CrO4) or insoluble barium chromate (BaCrO4), each alone at 360 micrograms Cr/m3 or in combination with 0.3 ppm O3. One day after the final exposure, rats were euthanized, their lungs were lavaged, and pulmonary macrophages (PAM) were recovered for assessment of basal and inducible functions. Rats inhaling K2CrO4-containing atmospheres had greater levels of total recoverable cells, neutrophils, and monocytes in bronchopulmonary lavage compared to rats exposed to insoluble Cr6+ atmospheres, O3 alone, or air; these rats also had a reduced percentage of PAM, although total PAM levels remained unaffected. Although Cr exposure-related changes in PAM functionality were evident, any dependence upon Cr solubility was variable. K2CrO4-containing atmospheres modulated PAM-inducible interleukins-1 and -6, and tumor necrosis factor-alpha production to a greater degree than those containing BaCrO4. Conversely, BaCrO4-containing atmospheres affected PAM basal nitric oxide production and interferon-gamma-primed/zymosan-stimulated reactive oxygen intermediate production to a greater extent than did those containing K2CrO4. In none of the PAM assays did co-inhalation of O3 result in a modulation of the effects obtained with either Cr6+ compound itself. The results indicate that, while immunomodulatory effects of inhaled Cr6+ upon PAM are related to particle solubility, the co-inhalation of O3 apparently does not cause further modifications of the metal-induced effects.

Biomarkers of immunotoxicity in fish and other non-mammalian sentinel species: predictive value for mammals?

Through the efforts of different laboratories, a battery of immunological assays is available to predict the immunotoxicity of xenobiotics. These assays, originally developed in rodents, have been adapted for use in a variety of animal species and are now used routinely in these models to assess the immunotoxicity of different chemical classes. For example, our laboratory has employed assays that measure antibody-forming cell response to T-dependent antigens, T- and B-cell lymphoproliferation, macrophage function, and host resistance against infectious bacteria to assess metal-induced immunotoxicity in laboratory-reared Japanese medaka (Oryzias latipes); immunologically-related assays measuring antioxidant activity have also been used in this capacity. Results of the aforementioned investigations have shown the usefulness of these endpoints to reliably demonstrate chemical-mediated immunotoxicity in teleost systems. Many of these same endpoints have also proved successful for predicting the immunotoxic effects of contaminated aquatic environments in feral fish populations. For example, smallmouth bass collected from a chlorinated hydrocarbon-contaminated site demonstrated significant changes in blood cell profiles and kidney phagocyte function compared to fish collected from a 'clean water' reference site. Some of these same immune parameters have also been used successfully to predict the immunotoxicity of polluted aquatic environments in feral populations of fish-eating birds and harbor seals. While interspecies extrapolation is difficult and should be approached with caution due to variables such as metabolism and pharmacokinetics, results from these studies demonstrate the usefulness of these immune assays to predict the immunomodulating effects of xenobiotics in fish and other wildlife species, as well as the applicability of fish to serve as additional/alternate animal models for mammalian species in immunotoxicological studies.

Effects of vanadium upon polyl:C-induced responses in rat lung and alveolar macrophages.

Hosts exposed to vanadium (V) display a subsequent decrease in their resistance to infectious microorganisms. Our earlier studies with rats inhaling occupationally relevant levels of V (as, ammonium metavanadate, NH4VO3) indicated that several nascent/inducible functions of pulmonary macrophages (PAM) were reduced. In the present study, V-exposed rats were examined to determine whether some of the same effects might also occur in situ. Rats were exposed nose-only to air or 2 mg V/m3 (as NH4VO3) for 8 h/d for 4 d, followed, 24 h later, by intratracheal (it) instillation of polyinosinic:polycytidilic acid (polyl:C) or saline. Analysis of lavaged lung cells/fluids after polyl:C instillation indicated that total lavageable cell/neutrophil numbers and protein levels, while significantly elevated in both exposure groups (as well as in saline-treated V-exposed rats), were always greater in V-exposed hosts. Exposure to V also affected the inducible production of interleukin 6 (IL-6) and interferon gamma (IFN gamma), but apparently not that of tumor necrosis factor-alpha (TNF alpha) or IL-1. Although polyl:C induced significant increases in lavage fluid IL-6 and IFN gamma levels in both exposure groups, levels were greater in V-exposed rats. If calculated with respect to total lavaged protein, however, V-exposed rats produced significantly less cytokine. Following polyl:C instillation, there were no marked exposure-related differences in basal or stimulated superoxide anion production by pooled lavaged cells or PAM specifically. With V-exposed rats, pooled cells recovered 24 h after saline instillation displayed reduced production (in both cases) compared to the air control cells; PAM-specific production was affected only after stimulation. In both exposure groups, polyl:C caused decreased superoxide production in recovered cells. Though less apparent with pooled cells, there was a time post polyl:C instillation-dependent decrease in stimulated PAM-specific superoxide production; this effect was greater in PAM from V-exposed rats than in PAM from air controls. Phagocytic activity of PAM from rats in both exposure groups was significantly increased by polyl:C instillation, although total activity in cells obtained from V-exposed rats was always significantly lower compared to air control cells. Our results indicate that short-term, repeated inhalation of occupationally relevant levels of V by rats modulates pulmonary immunocompetence. Modified cytokine production and PAM functionality in response to biological response modifiers (such as lipopolysaccharide, IFN gamma, or polyl:C) may be, at least in part, responsible for the increases in bronchopulmonary disease in humans occupationally exposed to V.