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Per- and polyfluoroalkyl substances (PFASs) are omnipresent and have been shown to induce a wide range of adverse effects, including hepatotoxicity, developmental toxicity and immunotoxicity. So far, little information is available about the mechanisms underlying the toxicity of PFASs, including those related to their immunotoxicity. Reported immunotoxic effects of PFASs include decreased antibody responses in experimental animals and humans, indicating that PFASs may, among others, affect B cell function. In the present study, we first assessed the effects of PFOA on the transcriptome of the human Namalwa B cell line using RNA seq analysis. Gene expression changes, analyzed using Ingenuity Pathway Analysis, pointed to various cellular processes affected by PFOA, including ‘B cell development’ and ‘Primary immunodeficiency signaling’. Interestingly, PFOA decreased the expression of RAG1 and RAG2, genes involved in immunoglobulin and T cell receptor V(D)J recombination. As a next step, time- and concentration-dependent changes in the expression of RAG1 and RAG2 upon exposure to PFOA, PFNA, PFHxS and PFOS were studied through RT-qPCR analysis. Analysis with the concentration–response modeling software PROAST resulted in the following potency ranking: PFNA > PFOA > PFOS > PFHxS. Altogether, the present in vitro study provides insights into the effects of selected PFASs on B cells, identifying RAG1 and RAG2 expression as possible relevant targets that may play a role in the immunotoxicity of PFASs.

Background Per- and polyfluoroalkyl substances (PFAS) are of public health concern, because of their ubiquitous and extremely persistent occurrence, and depending on their structure, their bio-accumulative, mobile and toxic properties. Human health effects associated with exposure to PFAS include adverse effects on the immune system. In 2020, EFSA (the European Food Safety Authority) defined adverse effects on the immune system as the most critical effect for human health risk assessment, based on reduced antibody responses to childhood vaccines and similar effects observed in experimental animal studies. Likewise, the U.S. EPA (Environmental Protection Agency) considers PFAS-induced immunotoxicity, especially in children, as the critical effect for risk assessment. However, the mechanisms by which antibody concentrations are impacted are not completely understood. Furthermore, other targets of the immune system functions have been reported in the literature. Objective The aim of this review is to explore PFAS-associated immune-related effects. This includes, relevant mechanisms that may underlie the observed effects on the immune system, immunosuppression as well as immunoenhancement, such as i) modulation of cell signalling and nuclear receptors, such as NF-κB and PPARs; ii) alteration of calcium signalling and homoeostasis in immune cells; iii) modulation of immune cell populations; iv) oxidative stress and v) impact on fatty acid metabolism & secondary effects on the immune system. Methods A literature research was conducted using three databases (Web of Science, PubMed, and Scopus), which were searched in July 2021 for relevant studies published in the time frame from 2018 to 2021. In total, 487 publications were identified as potentially eligible and following expert-based judgement, articles relevant for mechanisms of PFAS induced immunotoxicity are discussed. Conclusions Taken together, we show that there is substantial evidence from both in vitro and in vivo experimental as well as epidemiological studies, supporting that various PFAS, not only PFOA and PFOS, affect multiple aspects of the immune system. Timing of exposure is critical, because the developing immune system is especially vulnerable to toxic insults, resulting in a higher risk of particularly adverse immune effects but also other organs later in life.

There is a global research interest in metal nanoparticles (MNPs) due to their diverse applications, rapidly increasing use, and increased presence in the aquatic environment. Currently, most MNPs in the environment are at levels unlikely to cause overt toxicity. Sub-lethal effects that MNPs may induce, notable immunotoxicity, could however have significant health implications. Thus, deciphering the immunological interactions of MNPs with aquatic organisms constitutes a much-needed area of research. In this article, we critically assess the evidence for immunotoxic effects of MNPs in bivalves and fish, as key wildlife sentinels with widely differing ecological niches that are used as models in ecotoxicology. The first part of this review details the properties, fate, and fundamental physicochemical behavior of MNPs in the aquatic ecosystem. We then consider the toxicokinetics of MNP uptake, accumulation, and deposition in fish and bivalves. The main body of the review then focuses on immune reactions in response to MNPs exposure in bivalves and fish illustrating their immunotoxic potential. Finally, we identify major knowledge gaps in our current understanding of the implications of MNPs exposure for immunological functions and the associated health consequences for bivalves and fish, as well as the general lessons learned on the immunotoxic properties of the emerging class of nanoparticulate contaminants in fish and bivalves.

In many domains regulating chemicals and chemical products, there is a legal requirement to determine skin sensitivity to allergens. While many in vitro assays to detect contact hypersensitivity have been developed as alternatives to animal testing over the past ten years and significant progress has been made in this area, there is still a need for continued investment in the creation of techniques and strategies that will allow accurate identification of potential contact allergens and their potency in vitro. In silico models are promising tools in this regard. However, none of the state-of-the-art systems seems to function well enough to serve as a stand-alone hazard identification tool, especially in evaluating the possible allergenicity effects in humans. The Universal Immune System Simulator, a mechanistic computational platform that simulates the human immune system response to a specific insult, provides a means of predicting the immunotoxicity induced by skin sensitisers, enriching the collection of computational models for the assessment of skin sensitization. Here, we present a specific disease layer implementation of the Universal Immune System Simulator for the prediction of allergic contact dermatitis induced by specific skin sensitizers.

Inorganic arsenic is a well-known environmental toxicant and carcinogen, and there is overwhelming evidence for an association between this metalloid poisoning and hepatic diseases. However, the biological mechanism involved is not well characterized. In the present study, we probed how inorganic arsenic modulates the hepatic polarization of macrophages, as well as roles of PTEN-induced kinase 1 (PINK1)/Parkin-mediated mitophagy participates in regulating the metalloid-mediated macrophage polarization. Our results indicate that acute arsenic exposure induced macrophage polarization with up-regulated gene expression of inducible nitric oxide synthase (Inos) and arginase-1 (Arg1), monocyte chemotactic protein-1 (Mcp-1) and macrophage inflammatory protein-2 (Mip-2), tumor necrosis factor (Tnf)-α, interleukin (Il)-1β and Il-6, as well as anti-inflammatory factors Il-4 and Il-10. In parallel, we demonstrated the disrupted hepatic redox balance typically characterized by the up-regulation of hydrogen peroxide (H2O2) and glutathione (GSH), and activation of PINK1/Parkin-mediated mitophagy in the livers of acute arsenic-exposed mice. In addition, our results demonstrate that it might be the PINK1/Parkin-mediated mitophagy that renders hepatic macrophage refractory to arsenic-induced up-regulation of the genes Inos, Mcp-1, Mip-2, Tnf-α, Il-1β, Il-6 and Il-4. In this regard, this is the first time the protective effects of PINK1/Parkin-mediated mitophagy in inorganic arsenic-induced hepatic macrophage polarization in vivo have been reported. These findings add novel insights into the arsenical immunotoxicity and provide a basis for the preve.ntive and therapeutic potential of PINK1/Parkin-mediated mitophagy in arsenic poisoning.

Mercury (Hg) is a toxic trace metal ubiquitously distributed in the environment. Inorganic mercury (as HgCl2 ) can cause immunotoxicity in birds, but the mechanisms of action are still not fully resolved, especially with respect to responses to viral infections. To investigate the potential immunomodulatory effects of Hg2+ on specific cell types of the avian immune system, chicken macrophage (HD-11) and B-lymphocyte (DT40) cell lines were applied as in vitro models for the innate and adaptive immune systems, respectively. The cells were stimulated with synthetic double-stranded RNA, which can be recognized by toll-like receptor-3 to mimic a viral infection. The Hg2+ showed concentration-dependent cytotoxicity in both cell lines, with similar median effect concentrations at 30 µM. The cytotoxicity of Hg2+ was closely related to glutathione (GSH) depletion and reactive oxygen species induction, whereas the de novo synthesis of GSH acted as a primary protective strategy. Nitric oxide produced by activated macrophages was strongly inhibited by Hg2+ , and was also influenced by cellular GSH levels. Cell proliferation, gene expression of microRNA-155, and cellular IgM levels in B cells were decreased at noncytotoxic Hg2+ concentrations. The secretion of antiviral interferon-α was induced by Hg2+ in both cell lines. Overall, our results suggest that Hg2+ exposure can cause immunomodulatory effects in birds by disrupting immune cell proliferation and cytokine production, and might result in disorders of the avian immune system. Environ Toxicol Chem 2021;40:2813-2824. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Endocrine-disrupting chemicals (EDCs) refer to a group of chemicals that cause adverse effects in human health, impairing hormone production and regulation, resulting in alteration of homeostasis, reproductive, and developmental, and immune system impairments. The immunotoxicity of EDCs involves many mechanisms altering gene expression that depend on the activation of nuclear receptors such as the aryl hydrocarbon receptor (AHR), the estrogen receptor (ER), and the peroxisome proliferator- activated receptor (PPAR), which also results in skin and intestinal disorders, microbiota alterations and inflammatory diseases. This systematic review aims to review different mechanisms of immunotoxicity and immunomodulation of T cells, focusing on T regulatory (Treg) and Th17 subsets, B cells, and dendritic cells (DCs) caused by specific EDCs such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), bisphenols (BPs) and polyfluoroalkyl substances (PFASs). To achieve this objective, a systematic study was conducted searching various databases including PubMed and Scopus to find in-vitro, in-vivo, and biomonitoring studies that examine EDC-dependent mechanisms of immunotoxicity. While doing the systematic review, we found species- and cell-specific outcomes and a translational gap between in-vitro and in-vivo experiments. Finally, an adverse outcome pathway (AOP) framework is proposed, which explains mechanistically toxicity endpoints emerging from different EDCs having similar key events and can help to improve our understanding of EDCs mechanisms of immunotoxicity. In conclusion, this review provides insights into the mechanisms of immunotoxicity mediated by EDCs and will help to improve human health risk assessment. Overview of the mechanisms of immunotoxicity of EDCs for T, B, and Dendritic cells and the main outcomes of exposure that result in immunotoxicity: imbalance of Treg/Th17 lymphocyte populations; a decrease of antibodies production; an increase of DCs maturation. Abbreviations: 3’IgHRR: 3’immunoglobulin heavy chain regulatory region; AHR: Aryl hydrocarbon receptor; AIP: AHR-interacting protein; AO: Adverse outcome; AOP: Adverse outcome pathway; AP-1: Activator protein 1; APC: antigen-presenting cell; ARNT: AHR nuclear translocator; Bach2: BTB Domain And CNC Homolog 2; BMDL: Benchmark dose lower confidence limit; BCL-6: B-cell lymphoma 6 protein; BCR: B-cell receptor; BFR: Brominated flame retardant; Blimp-1: B lymphocyte-induced maturation protein-1; BMDC: Bone marrow dendritic cells; BP: Bisphenol; BPA: Bisphenol A; BPAF: Bisphenol A-F; BPF: Bisphenol F; BPS: Bisphenol S; CD: Cluster of differentiation; CDKN1A: Cyclin Dependent Kinase Inhibitor 1A; CK1: Casein kinase 1; CYP: Cytochrome P450; DC: Dendritic cell; DDT: Dichlorodiphenyltrichloroethane; Dec602: Dechlorane 602; DNA: Deoxyribonucleic acid; EDC: Endocrine-disrupting chemicals; EFSA: European Food Safety Authority; EPA: Environmental Protection Agency; ES: Estrogen receptor; FICZ: 6-Formylindolo(3,2-b)carbazole; FoxP3: Forkhead box P3; FR: Flame retardant; GvH: Graft vs host; HSP90: 90 KDa heat shock protein; i.p.: Intraperitoneal; IDO: Indoleamine 2,3-Dioxygenase; IFNc: Interferon gamma; Ig: Immunoglobulin; IgH: Immunoglobulin heavy chain; IgJ: Immunoglobulin J chain; Igj: Immunoglobulin j chain; IKK: IjB kinase; IL

The existence of a complex hormonal balance among glucocorticoids, androgens and estrogens involved in the regulation of Receptor for Activated C Kinase 1 (RACK1) expression and its related immune cells activation, highlights the possibility to employ this protein as screening tool for the evaluation of the immunotoxic profile of endocrine disrupting chemicals (EDCs), hormone-active substances capable of interfering with the physiologic hormonal signaling. Hence, the aim of this work was to investigate the effect of the exposure of EDCS 17α-ethynylestradiol (EE), diethyl phthalate (DEP) and perfluorooctanesulfonic acid (PFOS) on RACK1 expression and on lipopolysaccharide (LPS)-induced activation of the human monocytic cell line THP-1, a validated model for this investigation. In line with our previous results with estrogen-active compounds, EE treatment significantly induced RACK1 promoter transcriptional activity, mRNA expression, and protein levels, which paralleled an increase in LPS-induced IL-8, TNF-α production and CD86 expression, previously demonstrated to be dependent on RACK1/PKCβ activation. EE mediates its effect on RACK1 expression through G-protein-coupled estrogen receptor (GPER) and androgen receptor (AR) ligand-independent cascade, as also suggested by in silico molecular docking simulation. Conversely, DEP and PFOS induced a dose-dependent downregulation of RACK1 promoter transcriptional activity, mRNA expression, and protein levels, which was mirrored by a reduction of IL-8, TNF-α production and CD86 expression. Mifepristone pre-treatments abolish DEP and PFOS effects, confirming their GR agonist profile, also corroborated by molecular docking. Altogether, our data confirm that RACK1 represents an interesting target of steroid active compounds, which expression offers the opportunity to screen the immunotoxic potential of different hormone-active substances of concerns due to their human exposure and environmental persistence.

As a new alternative to perfluorooctane sulfonic acid (PFOS), 6:2 fluorotelomer sulfonic acid (6:2 FTSA) has been widely produced and used in recent years, and its concentration and frequency of detection in the aquatic environment and aquatic organisms are increasing. However, studies of its toxicity in aquatic biological systems are alarmingly scarce, and the relevant toxicological information needs to be improved. In this study, we investigated AB wild-type zebrafish (Danio rerio) embryos subjected to acute 6:2 FTSA exposure for immunotoxicity using immunoassays and transcriptomics. Immune indexes showed significant decreases in SOD and LZM activities, but no significant change in NO content. Other indexes (TNOS, iNOS, ACP, AKP activities, and MDA, IL-1β, TNF-α, NF-κB, TLR4 content) all showed significant increases. These results indicated that 6:2 FTSA induced oxidative stress and inflammatory responses in zebrafish embryos and exhibited immunotoxicity. Consistently, transcriptomics showed that genes involved in the MAPK, TLR and NOD-like receptor signaling pathways (hsp70, hsp701, stat1b, irf3, cxcl8b, map3k8, il1b, tnfa and nfkb) were significantly upregulated after 6:2 FTSA exposure, suggesting that 6:2 FTSA might induce immunotoxicity in zebrafish embryos through the TLR/NOD-MAPK pathway. The results of this study indicate that the safety of 6:2 FTSA should be examined further.

Wild rodents are natural hosts of Leptospira spp. and are exposed to various pesticides, some of which are immunotoxic. Rodent urine is an important source of infection for humans and other animals. We evaluated the effects of pesticide exposure on Leptospira growth in mice. Diazinon, at doses of 0.2, 1, and 5 mg/kg/day, was orally administered continuously to mice infected with Leptospira interrogans serogroup Hebdomadis for 32 days. The numbers of L. interrogans in urine and kidney tissues were significantly lower in mice exposed to 5 mg/kg/day diazinon than in unexposed mice (p < 0.05). The urinary concentration of 2-isopropyl-6-methyl-4-pyrimidinol, the metabolite of diazinon, was comparable with the concentration at which viability of L. interrogans was decreased in in vitro assay, suggesting that it had toxic effects on L. interrogans in the proximal renal tubules. Diazinon exposure reinforced Leptospira-induced expression of inflammatory cytokine genes in kidney tissues, and an enhanced immune system might suppress Leptospira growth. These results suggest that diazinon exposure may not increase the risk of Leptospira transmission to humans through mice. This novel study evaluated the relationship between pesticide exposure and Leptospira infection in mice, and the results could be useful for risk assessment of leptospirosis.

Background: There is wide, largely unexplained heterogeneity in immunological and clinical responses to SARS-CoV-2 infection. Numerous environmental chemicals, such as persistent organic pollutants (POPs) and chemical elements (including some metals, essential trace elements, rare earth elements, and minority elements), are immunomodulatory and cause a range of adverse clinical events. There are no prospective studies on the effects of such substances on the incidence of SARS-CoV-2 infection and COVID-19. Objective: To investigate the influence of blood concentrations of POPs and elements measured several years before the pandemic on the development of SARS-CoV-2 infection and COVID-19 in individuals from the general population. Methods: We conducted a prospective cohort study in 154 individuals from the general population of Barcelona. POPs and elements were measured in blood samples collected in 2016-2017. SARS-CoV-2 infection was detected by rRT-PCR in nasopharyngeal swabs and/or by antibody serology using eighteen isotype-antigen combinations measured in blood samples collected in 2020-2021. We analyzed the associations between concentrations of the contaminants and SARS-CoV-2 infection and development of COVID-19, taking into account personal habits and living conditions during the pandemic. Results: Several historically prevalent POPs, as well as arsenic, cadmium, mercury, and zinc, were not associated with COVID-19, nor with SARS-CoV-2 infection. However, DDE (adjusted OR = 5.0 [95% CI: 1.2-21]), lead (3.9 [1.0-15]), thallium (3.4 [1.0-11]), and ruthenium (5.0 [1.8-14]) were associated with COVID-19, as were tantalum, benzo(b)fluoranthene, DDD, and manganese. Thallium (3.8 [1.6-8.9]), and ruthenium (2.9 [1.3-6.7]) were associated with SARS-CoV-2 infection, and so were lead, gold, and (protectively) iron and selenium. We identified mixtures of up to five substances from several chemical groups, with all substances independently associated to the outcomes. Conclusions: Our results provide the first prospective and population-based evidence of an association between individual concentrations of some contaminants and COVID-19 and SARS-CoV-2 infection. POPs and elements may contribute to explain the heterogeneity in the development of SARS-CoV-2 infection and COVID-19 in the general population. If the associations are confirmed as causal, means are available to mitigate the corresponding risks.

Polybrominated diphenyl ethers (PBDEs) are classic and emerging pollutants that are potentially harmful to the human immune system. Research on their immunotoxicity and mechanisms suggests that they play an important role in the resulting pernicious effects of PBDEs. 2,2′,4,4′-Tetrabrominated biphenyl ether (BDE-47) is the most biotoxic PBDE congener, and, in this study, we evaluated its toxicity toward RAW264.7 cells of mouse macrophages. The results show that exposure to BDE-47 led to a significant decrease in cell viability and a prominent increase in apoptosis. A decrease in mitochondrial membrane potential (MMP) and an increase in cytochrome C release and caspase cascade activation thus demonstrate that cell apoptosis induced by BDE-47 occurs via the mitochondrial pathway. In addition, BDE-47 inhibits phagocytosis in RAW264.7 cells, changes the related immune factor index, and causes immune function damage. Furthermore, we discovered a significant increase in the level of cellular reactive oxygen species (ROS), and the regulation of genes linked to oxidative stress was also demonstrated using transcriptome sequencing. The degree of apoptosis and immune function impairment caused by BDE-47 could be reversed after treatment with the antioxidant NAC and, conversely, exacerbated by treatment with the ROS-inducer BSO. These findings indicate that oxidative damage caused by BDE-47 is a critical event that leads to mitochondrial apoptosis in RAW264.7 macrophages, ultimately resulting in the suppression of immune function.

The use of nanomaterials has been increasing in recent times, and they are widely used in industries such as cosmetics, drugs, food, water treatment, and agriculture. The rapid development of new nanomaterials demands a set of approaches to evaluate the potential toxicity and risks related to them. In this regard, nanosafety has been using and adapting already existing methods (toxicological approach), but the unique characteristics of nanomaterials demand new approaches (nanotoxicology) to fully understand the potential toxicity, immunotoxicity, and (epi)genotoxicity. In addition, new technologies, such as organs-on-chips and sophisticated sensors, are under development and/or adaptation. All the information generated is used to develop new in silico approaches trying to predict the potential effects of newly developed materials. The overall evaluation of nanomaterials from their production to their final disposal chain is completed using the life cycle assessment (LCA), which is becoming an important element of nanosafety considering sustainability and environmental impact. In this review, we give an overview of all these elements of nanosafety., European Union’s H2020 project Sinfonia (N.857253). SbDToolBox, with reference NORTE-01-0145-FEDER-000047, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund

The gastrointestinal tract (GIT) is exposed to xenobiotics, including drugs, through both: local (oral) and systemic routes. Despite the advances in drug discovery and in vitro pre-clinical models, there is a lack of appropriate translational models to distinguish the impact of these routes of exposure. Changes in intestinal permeability has been observed in different gastrointestinal and systemic diseases. This study utilized one such xenobiotic, arsenic, to which more than 200 million people around the globe are exposed via their food, drinking water, work environment, soil, and air. The purpose of this study was to establish an in vitro model to mimic gastrointestinal tract exposure to xenobiotics via oral or intravenous routes. To achieve this, we compared the route (mimicking oral and intravenous exposure to GIT and the dose response (using threshold approach) of trivalent and pentavalent inorganic arsenic species on the permeability of in vitro cultured polarized T84 cells, an example of intestinal epithelial cells. Arsenic treatment to polarized T84 cells via the apical and basolateral compartment of the trans-well system reflected oral or intravenous routes of exposure in vivo, respectively. Sodium arsenite, sodium arsenate, dimethyl arsenic acid sodium salt (DMAV), and disodium methyl arsonate hydrate (MMAV) were assessed for their effects on intestinal permeability by measuring the change in trans-epithelial electrical resistance (TEER) of T-84 cells. Polarized T-84 cells exposed to 12.8 µM of sodium arsenite from the basolateral side showed a marked reduction in TEER. Cytotoxicity of sodium arsenite, as measured by release of lactate dehydrogenase (LDH), was increased when cells were exposed via the basolateral side. The mRNA expression of genes related to cell junctions in T-84 cells was analyzed after exposure with sodium arsenite for 72 h. Changes in TEER correlated with mRNA expression of focal-adhesion-, tight-junction- and gap-junction-related genes (upregulation of Jam2, Itgb3 and Notch4 genes and downregulation of Cldn2, Cldn3, Gjb1, and Gjb2). Overall, exposure to sodium arsenite from the basolateral side was found to have a differential effect on monolayer permeability and on cell-junction-related genes as compared to apical exposure. Most importantly, this study established a preclinical human-relevant in vitro translational model to assess the changes in permeability and cytotoxicity during exposure, mimicking oral or intravenous routes.

Immunotoxicity hazard identification of chemicals aims to evaluate the potential for unintended effects of chemical exposure on the immune system. Perfluorinated alkylate substances (PFAS), such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are persistent, globally disseminated environmental contaminants known to be immunotoxic. Elevated PFAS exposure is associated with lower antibody responses to vaccinations in children and in adults. In addition, some studies have reported a correlation between PFAS levels in the body and lower resistance to disease, in other words an increased risk of infections or cancers. In this context, modelling and simulation platforms could be used to simulate the human immune system with the aim to evaluate the adverse effects that immunotoxicants may have. Here, we show the conditions under which a mathematical model developed for one purpose and application (e.g., in the pharmaceutical domain) can be successfully translated and transferred to another (e.g., in the chemicals domain) without undergoing significant adaptation. In particular, we demonstrate that the Universal Immune System Simulator was able to simulate the effects of PFAS on the immune system, introducing entities and new interactions that are biologically involved in the phenomenon. This also revealed a potentially exploitable pathway for assessing immunotoxicity through a computational model.

Background A strong immune system is a primary requirement to keep the body safe from different ailments and infections. A human knowingly or unknowingly often comes to the exposure of many foreign substances such as pollutants, chemicals, metals and drugs that affect the immune system. Though some of these substances are known to exert immunotoxicity, their precise role as immunotoxicant is still unidentified, hence, the testing of these substances has to be taken into account. The present manuscript aimed to explore the mechanism behind immunotoxicity, biomarkers involved, manifestations, testing of immunotoxicity and its management. Methods Relevant literature on immunotoxicity, collected from online scientific databases like Scopus, PubMed and Google Scholar, was rigorously reviewed. Results Earlier reports showed that immunotoxic effects of chemicals and pharmaceuticals may cause various health problems including allergic reactions, skin disorders, respiratory infections, gastrointestinal problems, and autoimmune disorders. If diagnosed in time, many of these conditions can be managed with the help of existing treatments although the complete treatment is sometimes a big challenge. Conclusion Based on the review of available literature, it can be concluded that immunotoxicity is one of the key factors responsible for several infectious diseases, autoimmune disorders and even cancers. Hence, the requirement of advanced diagnostic tools and established treatments for immunotoxicity is highly recommended.

The prevalence of unconventional oil and gas (UOG) operations raises concerns regarding the potential for adverse health outcomes following exposure to water tainted by mixtures of UOG associated chemicals. The potential effects that exposure to complex chemical mixtures has on the immune system have yet to be fully evaluated. In this study, effects on the immune system of adult mice exposed to a mixture of 23 chemicals that have been associated with water near active UOG operations were investigated. Female and male mice were exposed to the mixture via their drinking water for at least 8 weeks. At the end of the exposure, cellularity of primary and secondary immune organs, as well as an immune system function, were assessed using three different models of disease, i.e. house dust mite (HDM)-induced allergic airway disease, influenza A virus infection, and experimental autoimmune encephalomyelitis (EAE). The results indicated exposures resulted in different impacts on T-cell populations in each disease model. Furthermore, the consequences of exposure differed between female and male mice. Notably, exposure to the chemical mixture significantly increased EAE disease severity in females, but not in male, mice. These findings indicated that direct exposure to this mixture leads to multiple alterations in T-cell subsets and that these alterations differ between sexes. This suggested to us that direct exposure to UOG-associated chemicals may alter the adult immune system, leading to dysregulation in immune cellularity and function.

En los últimos años, la producción de nanopartículas (NPs) ha aumentado dando lugar a que su liberación al medio ambiente haya incrementado. Tanto la liberación ambiental como su desecho se está convirtiendo en una preocupación emergente ya que las NPs alcanzarían los ecosistemas terrestres como acuáticos, presentando problemas de toxicidad para los organismos vivos. En los ecosistemas terrestres, las lombrices de tierra Eisenia andrei son invertebrados típicamente utilizados como organismos modelo en estudios de ecotoxicidad con un sistema inmunológico innato que protege a los animales contra contaminantes, bacterias, hongos y virus que se encuentran en el suelo. El objetivo general de esta tesis doctoral fue evaluar los efectos tóxicos de las NPs de TiO2, las NPs de CuO y las NPs de Ag2S en E. andrei y estudiar la interacción de las NPs con las células inmunocompetentes de E. andrei llamadas celomocitos mediante ensayos in vitro e in vivo. Los puntos finales evaluados durante la tesis doctoral fueron el estrés oxidativo (producción de ROS, de NO y de MDA), la genotoxicidad, los biomarcadores inmunitarios (actividad feneloxidasa, actividad fagocítica) y los niveles de ARN mensajero (ARNm). Los experimentos de toxicidad de las NPs de TiO2 y las NPs de CuO fueron realizadas in vitro con celomocitos de E. andrei a 1, 10 y 100 µg mL-1, a las 2, 6 y 24 h de exposición. Los experimentos realizados con las NPs de Ag2S se llevaron a cabo in vivo donde 180 lombrices de tierra E. andrei fueron expuestas a 5 mg Ag Kg-1 de suelo de las NPs de Ag2S durante 14 días siguiendo la directriz OECD 207. La caracterización de las NPs se realizó mediante la dispersión de luz de difracción de múltiples ángulos (MADLS), microscopio electrónico de transmisión (TEM) y de barrido (SEM). Además, el TEM y SEM se utilizaron en los análisis in vitro para localizar las NPs de TiO2 y las NPs de CuO en los celomocitos. Los resultados de las pruebas in vitro mostraron que la disponibilidad de las NPs de TiO2 y las NPs de CuO difería entre ellas dentro del medio de cultivo celular. Las NPs de TiO2 fueron más estables y tendieron a precipitar a las 24 h, mientras que las NPs de CuO fueron más inestables. A través del TEM, se observó que los celomocitos fueron capaces de engullir las NPs de CuO. Las NPs de TiO2 y Ag2S no produjeron tantos daños a los celomocitos como las NPs de CuO en ninguno de los puntos finales mencionados anteriormente. En conclusión, se demostró que las NPs de TiO2 y NPs de CuO y las NPs de Ag2S pueden afectar a las lombrices de tierra. Se destacó que las células HAs y las células GAs fueron objetivos de las NPs, ya que pudieron engullir a las NPs. En cuanto al mecanismo de defensa de los celomocitos, se observó que los HAs y los GAs fueron capaces de aumentar las enzimas antioxidantes para disminuir el estrés oxidativo producido por la exposición con las NPs. In recent years, the production of nanoparticles (NPs) has increased exponentially, leading to an increase in their release into the environment. The environmental release of NPs and their disposal is becoming an emerging concern since they can reach both terrestrial and aquatic ecosystems, producing toxicity problems for living organisms. In terrestrial ecosystems, Eisenia andrei earthworms are invertebrates typically used as model organisms in ecotoxicity studies that possess an innate immune system that protects animals against contaminants, bacteria, fungi, and viruses that can be found in the soil. The general objective of this doctoral thesis was to evaluate the toxic effects of TiO2 NPs, CuO NPs and Ag2S NPs in E. andrei and to study the interaction of NPs with immunocompetent cells of E. andrei called coelomocytes by means of assays in vitro and in vivo. The endpoints evaluated during the doctoral thesis were oxidative stress (ROS, NO and MDA production), genotoxicity, immune biomarkers (phenoloxidase activity, phagocytic activity) and messenger RNA (mRNA) levels. The toxicity experiments of the TiO2 NPs and the CuO NPs were carried out in vitro with E. andrei coelomocytes at 1, 10 and 100 µg mL-1 and at 2, 6 and 24 h of exposure. The experiments carried out with the Ag2S NPs were carried out in vivo where 180 E. andrei earthworms were exposed to 5 mg Ag Kg-1 of the soil of the Ag2S NPs for 14 days following the OECD 207 guideline. The characterization of NPs was performed using multi-angle diffraction light scattering (MADLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Furthermore, TEM and SEM were used in in vitro analyses to localize TiO2 NPs and CuO NPs in coelomocytes. The results of the in vitro tests showed that the availability of TiO2 NPs and CuO NPs differed from each other within the cell culture medium. TiO2 NPs were more stable and tended to precipitate after 24 h, while CuO NPs were more unstable. Through TEM, it was observed that coelomocytes were able to engulf CuO NPs. TiO2 NPs and Ag2S NPs did not cause as much damage to coelomocytes as CuO NPs at any of the endpoints mentioned above. In conclusion, it was shown that TiO2 NPs and CuO NPs and Ag2S NPs can affect earthworms. It was highlighted that HAs and GAs were key targets of NPs, as they were able to engulf NPs. Regarding the defence mechanism of coelomocytes, it was observed that HAs and GAs were able to increase antioxidant enzymes to reduce the oxidative stress produced by exposure to NPs.

This work was supported by the National Institute of Environmental Health Sciences (NIEHS) (grant R01ES031657) . We thank investigators and participants of the National Health and Nutrition Examination Study (NHANES) ., Background: Per- and polyfluoroalkyl substances (PFAS) exert immunosuppressive effects in experimental animals. Few epidemiologic studies investigated PFAS exposure and immune-related clinical outcomes such as common cold, especially during childhood when the immune system is developing. Methods: This study used data from the National Health and Nutrition Examination Survey and included 517 children 3–11 years (2013–2014 cycle) and 2732 adolescents 12–19 years (2003–2016 cycles). Serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) were quantified. Common cold was self-reported by the participant or parent as having a head cold or chest cold in the last month. Multivariable logistic regression models were applied to examine the covariate-adjusted odds ratios (ORs) between individual PFAS concentrations and common cold incidence in the past month. The joint effect of PFAS mixtures was evaluated using Probit Bayesian Kernel Machine Regression (BKMR). Results: A doubling of serum PFHxS concentration was associated with a 31% higher odds (OR = 1.31, 95% CI: 1.06, 1.62) of common cold among children. Serum PFNA (OR = 1.36, 95% CI: 0.93, 1.98) and PFOA (OR = 1.32, 95% CI: 0.67, 2.62) concentrations were also related to common cold among children, as were serum PFOS concentrations among adolescents (OR = 1.13, 95% CI: 0.96, 1.32). ORs were higher in male than female children and adolescents. BKMR showed a clear increasing trend of common cold estimates across quantiles of the total PFAS mixture concentration among children, while no obvious pattern emerged in adolescents. Discussion: Among children in the United States, serum concentrations of PFAS mixtures, especially PFHxS and PFNA, were associated with higher odds of common cold. Among adolescents, PFOS was associated with increased common cold in the last month. This study contributes to the existing evidence supporting the immunotoxicity of PFAS in childhood and adolescence., United States Department of Health & Human Services National Institutes of Health (NIH) - USA, NIH National Institute of Environmental Health Sciences (NIEHS) R01ES031657 National Health and Nutrition Examination Study (NHANES)

Increasing use of nano-enabled products provides many benefits in various industrial processes and medical applications, but it also raises concern about release of nanoparticles (NPs) into the environment and subsequent human exposure. While potential toxicity of individual NPs types has been well described in scientific literature, exposure and health-related effects of nanomixtures has been poorly described. This study aimed to evaluate the combined effect of silver (AgNP) and polystyrene NPs (PSNP) on the human macrophages. AgNP are one of the most commercialized NPs due to efficient antimicrobial activity, while PSNP are ubiquitous in terrestrial and aquatic environments due to plastic pollution and degradation of polystyrene-based products. Differentiated monocytic cell line THP-1 were used as an in vitro model of human macrophages. Multiple aspects of cellular response to AgNP-PSNP nanomixture were analyzed including cell death, induction of apoptosis, oxidative stress response, expression of pro- and anti-inflammatory cytokines, and nanomechanical properties of cells. NPs uptake was visualized by confocal microscopy and quantified using flow cytometry. Results show that nanomixture increased apoptosis and cell death, expression of IL-6, IL-8 and TNFa, oxidative stress and mitochondrial dysfunction in cells compared to AgNP and PSNP applied as single treatments, indicating mixture additive action. Anti-inflammatory cytokines IL1b, IL-4 and IL-10 were not affected by combined exposure compared to single NPs. Visualization of NPs uptake and internalization showed that AgNP and PSNP were localized mostly in cytoplasm, with small fraction of AgNP translocated into cell nuclei, which explain increased number of double-stranded DNA breaks following exposure of cells to AgNPs alone or in the mixture. Study outcomes represent clear warnings on the human co-exposure to AgNP and PSNP that needs to be implemented in risk assessment approaches towards toxic-free environment.

Cyanobacteria (blue-green algae) have been present on Earth for over 2 billion years, and can produce a variety of bioactive molecules, such as cyanotoxins. Microcystins (MCs), the most frequently detected cyanotoxins, pose a threat to the aquatic environment and to human health. The classic toxic mechanism of MCs is the inhibition of the protein phosphatases 1 and 2A (PP1 and PP2A). Immunity is known as one of the most important physiological functions in the neuroendocrine-immune network to prevent infections and maintain internal homoeostasis in fish. The present review aimed to summarize existing papers, elaborate on the MC-induced immunotoxicity in fish, and put forward some suggestions for future research. The immunomodulatory effects of MCs in fish depend on the exposure concentrations, doses, time, and routes of exposure. Previous field and laboratory studies provided strong evidence of the associations between MC-induced immunotoxicity and fish death. In our review, we summarized that the immunotoxicity of MCs is primarily characterized by the inhibition of PP1 and PP2A, oxidative stress, immune cell damage, and inflammation, as well as apoptosis. The advances in fish immunoreaction upon encountering MCs will benefit the monitoring and prediction of fish health, helping to achieve an ecotoxicological goal and to ensure the sustainability of species. Future studies concerning MC-induced immunotoxicity should focus on adaptive immunity, the hormesis phenomenon and the synergistic effects of aquatic microbial pathogens.

Cyanotoxin occurrence is gaining importance due to anthropogenic activities, climate change and eutrophication. Among them, Microcystins (MCs) and Cylindrospermopsin (CYN) are the most frequently studied due to their ubiquity and toxicity. Although MCs are primary classified as hepatotoxins and CYN as a cytotoxin, they have been shown to induce deleterious effects in a wide range of organs. However, their effects on the immune system are as yet scarcely investigated. Thus, to know the impact of cyanotoxins on the immune system, due to its importance in organisms’ homeostasis, is considered of interest. A review of the scientific literature dealing with the immunotoxicity of MCs and CYN has been performed, and both in vitro and in vivo studies have been considered. Results have confirmed the scarcity of reports on the topic, particularly for CYN. Decreased cell viability, apoptosis or altered functions of immune cells, and changed levels and mRNA expression of cytokines are among the most common effects reported. Underlying mechanisms, however, are still not yet fully elucidated. Further research is needed in order to have a full picture of cyanotoxin immunotoxicity. Ministerio de Ciencia, Innovación y Universidades PID2019-104890RB-I00 Ministerio de Economia, Industria y Competitividad - FPI grant number BES-2016-078773

Fumonisin B1 (FB1) is a common mycotoxin contamination in agricultural commodities being considered as a significant risk to human and livestock health, while the mechanism of FB1 immunotoxicity are less understood, especially in chicken. Given that extracellular traps as a novel defense mechanism of leukocytes play an important role against foreign matters, in this study we aimed to investigate the effects of FB1 on chicken heterophil extracellular traps (HETs) formation. Our result showed that FB1 induced HETs release in chicken heterophils observed via immunostaining, and it was concentration-dependent during 10 to 40 μM. Moreover, in 40 μM FB1-exposed chicken heterophils, reactive oxygen species (ROS) level was increased, while catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity and glutathione (GSH) content were decreased. Simultaneously, FB1 (40 μM) activated ERK and p38 MAPK signaling pathways via increasing the phosphorylation level of ERK and p38 proteins. However, pretreatment of SB202190, U0126, and diphenyleneiodonium chloride (DPI) did not change FB1-triggered ROS production and HETs formation, suggesting FB1-induced HETs was a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, p38, and extracellular regulated protein kinases (ERK) signaling pathways-independent process. Inhibition of peptidyl arginine deiminase 4 (PAD4) enzyme and P2 × 1 receptor showed their vital role in 40 μM FB1-triggered HETs. This study reported for the first time that 40 μM FB1 induced the release of HETs in heterophils, and it was related to ROS production, PAD4, and P2 × 1, but was independent of NADPH oxidase, p38 and ERK signaling pathways, which might provide a whole novel perspective of perceiving and understanding the role of FB1 in immunotoxicity.

Background: Hepatic and renal damage is a cisplatin (Cis)-induced deleterious effect that is a major limiting factor in clinical chemotherapy. Objectives: The current study was designed to investigate the influence of pretreatment with olive leaf extract (OLE), bone-marrow-derived mesenchymal stem cells (BM-MSC), and their conditioned media (CM-MSC) against genotoxicity, nephrotoxicity, hepatotoxicity, and immunotoxicity induced by cisplatin in rats. Methods: The rats were randomly divided into six groups (six rats each) as follows: Control; OLE group, treated with OLE; Cis group, treated with a single intraperitoneal dose of Cis (7 mg/kg bw); Cis + OLE group, treated with OLE and cisplatin; Cis + CM-MSC group, treated with BM-MSC conditioned media and Cis; and Cis + MSC group, treated with BM-MSC in addition to Cis. Results: Cis resulted in a significant deterioration in hepatic and renal functions and histological structures. Furthermore, it increased inflammatory markers (TNF-α, IL-6, and IL-1β) and malondialdehyde (MDA) levels and decreased glutathione (GSH) content, total antioxidant capacity (TAC), catalase (CAT), and superoxide dismutase (SOD) activity in hepatic and renal tissues. Furthermore, apoptosis was evident in rat tissues. A significant increase in serum 8-hydroxy-2-deoxyguanosine (8-OH-dG), nitric oxide (NO) and lactate dehydrogenase (LDH), and a decrease in lysozyme activity were detected in Cis-treated rats. OLE, CM-MSC, and BM-MSC have significantly ameliorated Cis-induced deterioration in hepatic and renal structure and function and improved oxidative stress and inflammatory markers, with preference to BM-MSC. Moreover, apoptosis was significantly inhibited, evident from the decreased expression of Bax and caspase-3 genes and upregulation of Bcl-2 proteins in protective groups as compared to Cis group. Conclusions: These findings indicate that BM-MSC, CM-MSC, and OLE have beneficial effects in ameliorating cisplatin-induced oxidative stress, inflammation, and apoptosis in the hepatotoxicity, nephrotoxicity, immunotoxicity, and genotoxicity in a rat model.

(1) Background: Graphene is a two-dimensional atomic structure with a wide range of uses, including for biomedical applications. However, knowledge of its hazards is still limited. This work brings new cytotoxic, cytostatic, genotoxic and immunotoxic data concerning the in vitro exposure of human cell line to two types of graphene platelets (GP). It also contributes to the formation of general conclusions about the health risks of GP exposure. (2) Methods: In vitro exposure of a THP-1 cell line to three concentrations of two GP over 40 h. The cytotoxic potential was assessed by the measurement of LDH and glutathione (ROS) and by a trypan blue exclusion assay (TBEA), the cytostatic and genotoxic potential were assessed by the cytokinesis-block micronucleus (CBMN) test, and the immunotoxic potential was assessed by the measurement of IL-6, IL-10 and TNF-α. (3) Results: We found a significant dose-dependent increase in DNA damage (CBMN). The lowest observed genotoxic effect levels (LOGEL) were 5 µg/mL (GP1) and 30 µg/mL (GP2). We found no significant leaking of LDH from cells, increase in dead cells (TBEA), induction of ROS, increased levels of cytostasis, or changes in IL-6, IL-10 and TNF-α levels. (4) Conclusions: The genotoxicity increased during the short-term in vitro exposure of THP-1 to two GP. No increase in cytotoxicity, immunotoxicity, or cytostasis was observed.

Two-dimensional (2D) materials have emerged as an important class of nanomaterials for technological innovation due to their remarkable physicochemical properties, including sheet-like morphology and minimal thickness, high surface area, tuneable chemical composition, and surface functionalization. These materials are being proposed for new applications in energy, health, and the environment; these are all strategic society sectors toward sustainable development. Specifically, 2D materials for nano-imaging have shown exciting opportunities in in vitro and in vivo models, providing novel molecular imaging techniques such as computed tomography, magnetic resonance imaging, fluorescence and luminescence optical imaging and others. Therefore, given the growing interest in 2D materials, it is mandatory to evaluate their impact on the immune system in a broader sense, because it is responsible for detecting and eliminating foreign agents in living organisms. This mini-review presents an overview on the frontier of research involving 2D materials applications, nano-imaging and their immunosafety aspects. Finally, we highlight the importance of nanoinformatics approaches and computational modeling for a deeper understanding of the links between nanomaterial physicochemical properties and biological responses (immunotoxicity/biocompatibility) towards enabling immunosafety-by-design 2D materials.

When conducting histopathological evaluation of lymphoid tissues, it is necessary to know the variability and strain differences in histological features of different sites of lymphoid tissues. To investigate in detail the variability of lymphoid tissues and strain differences of control rats as well as those of immune reactivity and sensitivity to immunosuppression, we performed a histopathological analysis of various lymphoid tissues in conjunction with the evaluation of immune function in a T cell-dependent antibody response (TDAR) assay with cyclophosphamide (CP) in Sprague Dawley (SD) and F344 rats. Six-week-old male SD and F344 rats were orally treated with CP at 0 (control) or 4 mg/kg/day for 28 days; keyhole limpet hemocyanin (KLH) was introduced intravenously on Days 14 and 23, and the serum concentrations of anti-KLH antibodies were measured. HE staining and immunohistochemistry for T-cell (CD3) and B-cell (CD45RA) markers were performed using tissues from the spleen, thymus, and various lymph nodes. In CP-treated rats of both strains, decreased concentrations of anti-KLH antibodies were observed. Histopathological analysis revealed decreased lymphocytes mainly in the B-cell area, and these changes induced by CP treatment were more prominent in the F344 rats than in the SD rats. The present study also demonstrated that some of the lymphoid tissues of the control F344 rats were less developed than those of the control SD rats, suggesting that F344 rats might be easily affected by CP-induced immunosuppression. This information concerning rat strain differences in lymphoid tissues will be useful in histopathological evaluation for drug-induced immunotoxicity.

Therapeutic DNA-vaccination against drug-resistant HIV-1 may hinder emergence and spread of drug-resistant HIV-1, allowing for longer successful antiretroviral treatment (ART) up-to relief of ART. We designed DNA-vaccines against drug-resistant HIV-1 based on consensus clade A integrase (IN) resistant to raltegravir: IN_in_r1 (L74M/E92Q/V151I/N155H/G163R) or IN_in_r2 (E138K/G140S/Q148K) carrying D64V abrogating IN activity. INs, overexpressed in mammalian cells from synthetic genes, were assessed for stability, route of proteolytic degradation, and ability to induce oxidative stress. Both were found safe in immunotoxicity tests in mice, with no inherent carcinogenicity: their expression did not enhance tumorigenic or metastatic potential of adenocarcinoma 4T1 cells. DNA-immunization of mice with INs induced potent multicytokine T-cell response mainly against aa 209–239, and moderate IgG response cross-recognizing diverse IN variants. DNA-immunization with IN_in_r1 protected 60% of mice from challenge with 4Tlluc2 cells expressing non-mutated IN, while DNA-immunization with IN_in_r2 protected only 20% of mice, although tumor cells expressed IN matching the immunogen. Tumor size inversely correlated with IN-specific IFN-γ/IL-2 T-cell response. IN-expressing tumors displayed compromised metastatic activity restricted to lungs with reduced metastases size. Protective potential of IN immunogens relied on their immunogenicity for CD8+ T-cells, dependent on proteasomal processing and low level of oxidative stress.

Despite the widespread use of silver nanoparticles (AgNPs) in different fields and the amount of investigations available, to date, there are many contradictory results on their potential toxicity. In the present study, extensively characterized 20-nm AgNPs were investigated using optimized protocols and standardized methods to test several toxicological endpoints in different cell lines. The agglomeration/aggregation state of AgNPs in culture media was measured by dynamic light scattering (DLS). DNA and chromosomal damage on BEAS-2B and RAW 264.7 cells were evaluated by comet and micronucleus assays, while oxidative DNA damage by modified comet assay and 8-oxodG/8-oxodA detection. We also investigated immunotoxicity and immunomodulation by cytokine release and NO production in RAW 264.7 and MH-S cells, with or without lipopolysaccharide (LPS) stimulus. Transmission electron microscope (TEM) analysis was used to analyze cellular uptake of AgNPs. Our results indicate different values of AgNPs hydrodynamic diameter depending on the medium, some genotoxic effect just on BEAS-2B and no or slight effects on function of RAW 264.7 and MH-S in absence or presence of LPS stimulus. This study highlights the relevance of using optimized protocols and multiple endpoints to analyze the potential toxicity of AgNPs and to obtain reliable and comparable results.

Sulfometuron methyl (SM) is a widely used herbicide and thus leading to accumulation in the environment. The toxicity assessments of SM in model organisms are currently rare. In the present study, zebrafish were utilized for evaluating the detrimental effects of SM in aquatic vertebrates. Zebrafish embryos were exposed to 0, 10, 20, and 40 mg/L SM from 5.5 to 72 h post-fertilization (hpf), respectively. Consequently, SM exposure resulted in increasing the mortality rate and reducing hatching rate in larval zebrafish at 10, 20, and 40 mg/L SM-treated groups. The reduced numbers of immune cells (neutrophils and macrophages) were observed after SM exposure by a dose-dependent manner. The inflammatory responses (TLR4, MYD88, IL-1β, IL-6, IL-8, IFN-γ, IL-10, and TGF-β) were measured to estimate immune responses. Anti-inflammatory factors (IL-10 and TGF-β) were down-regulated in all the treated groups and significantly altered at 40 mg/L exposure group. Additionally, behavioral tests suggested that SM treatment significantly increased the total distance, average speed, and maximum acceleration of larval zebrafish during light-dark transition and subsequently enzymology test displayed the same trend to locomotor behaviors. The content significantly increased in oxidative stress, as reflected in ROS level in all the treated groups. The numbers of cell apoptosis were significantly increased at 20, and 40 mg/L and the highest concentration group induced the substantial increment (P

Deoxynivalenol (DON) is considered to be a grave threat to humans and animals. Ginsenoside Rb1 (Rb1) has been reported for its antioxidant potential and medicinal properties. However, the shielding effects of Rb1 and the precise molecular mechanisms against DON-induced immunotoxicity in mice have not been reported yet. In the present research, 4-weeks old healthy C57BL/6 mice were randomly assigned into four experimental groups (n = 12), viz., CON, DON 3 mg/kg BW, Rb1 50 mg/kg BW and DON 3 mg/kg + Rb1 50 mg/kg BW (DON + Rb1). Feed intake and body weight gain were monitored during the entire experiment (15 d). Our results demonstrated that Rb1 markedly increased the ADG (30%) and ADFI (25.10%) of mice compared with DON group. Furthermore, Rb1 alleviated the DON-induced immune injury by relieving the splenic histopathological alteration, enhancing the T-lymphocytes subsets (CD4+, CD8+), the levels of cytokines (IL-2, IL-6, IFN-γ, and TNF-α), as well as production of immunoglobulins (IgA, IgM, and IgG). Moreover, Rb1 ameliorated DON-inflicted oxidative stress by reducing the ROS, MDA and H2O2 contents and boosting the antioxidant defense system (T-AOC, T-SOD, CAT, and GSH-Px). Additionally, Rb1 significantly reversed the DON-induced excessive splenic apoptosis via modulating the mitochondria-mediated apoptosis pathway in mice, depicting the decreased percentage of splenocyte apoptotic cells by 26.65%, down-regulated the mRNA abundance of Bax, caspase-3, caspase-9, and protein expression of Bax, cleaved caspase-3, and Cyt-c. Simultaneously, Rb1 markedly rescued both Bcl-2 mRNA and protein expression levels. Taken together, Rb1 mitigates DON-induced immune injury by suppressing the oxidative damage and regulating the mitochondria-mediated apoptosis pathway in mice. Conclusively, our current research provides an insight into the preventive mechanism of Rb1 against DON-induced immune injury in mice and thus, presents a scientific baseline for the therapeutic application of Rb1.

Perfluorooctanoic acid (PFOA) is one of the most commonly used perfluorinated chemicals in industry. Wide concerns of PFOA toxicity are increased in recent years. However, report on immunotoxicity of PFOA was quite limited. This study aimed to investigate the immunotoxicity of PFOA exposure on macrophage RAW264.7. We assessed the effects of PFOA exposure on macrophage cell viability, cell apoptosis and cellular ROS level, and detected prominent cytokines release by RAW264.7. The results indicated that the cell viability of macrophage RAW264.7 was decreased by PFOA in dose- and time-dependent manners. Specifically, the exposure of 200 μM PFOA significantly increased apoptosis and ROS generation in macrophage, and thus caused cell damage. The ELISA results displayed that 100 μM PFOA exposure induced macrophage activation and enhanced cytokines secretion, including TNF-α, IL-1, IL-6, and IL-12. We also conducted nontargeted metabolomics based on LC-MS/MS and unveiled the perturbed metabolic pathways in macrophages induced by sublethal doses of PFOA (10 μM and 100 μM). Remarkably, global metabolomics results displayed that 10 μM PFOA exposure affected glutamine related pathways and the exposure at 100 μM conspicuously changed glutathione and fatty acid oxidation metabolism. These findings showed that 10 μM PFOA exposure could impel metabolic reprogramming of macrophage to trigger inflammatory response, although such dose displayed no obvious effect on cell viability, cellular ROS or apoptosis events of macrophage RAW264.7.

Metal oxide nanoparticles are widely used in both consumer products and medical applications, but the knowledge regarding exposure-related health effects is limited. However, it is challenging to investigate nanoparticle interaction processes with biological systems. The overall aim of this project was to improve the possibility to predict exposure-related health effects of metal oxide nanoparticles through interdisciplinary collaboration by combining workflows from the pharmaceutical industry, nanomaterial sciences, and occupational medicine. Specific aims were to investigate nanoparticle-protein interactions and possible adverse immune reactions. Four different metal oxide nanoparticles; CeOx nanocrystals with 5% or 14% Gd, Co3O4, and Fe2O3, were characterized by dynamic light scattering and high-resolution transmission electron microscopy. Nanoparticle-binding proteins were identified and screened for HLA-binding peptides in silico. Monocyte interaction with nanoparticle-protein complexes was assessed in vitro. Herein, for the first time, immunogenic properties of nanoparticle-binding proteins have been characterized. The present study indicates that especially Co3O4-protein complexes can induce both danger signals, verified by the production of inflammatory cytokines and simultaneously bind autologous proteins, which can be presented as immunogenic epitopes by MHC class II. The clinical relevance of these findings should be further evaluated to investigate the role of metal oxide nanoparticles in the development of autoimmune disease. The general workflow identified experimental difficulties, such as nanoparticle aggregate formation and a lack of protein-free buffers suitable for particle characterization, protein analyses, as well as for cell studies. This confirms the importance of future interdisciplinary collaborations. Funding Agencies|Region Ostergotland ALF [LIO-606891]; AFA insurances [150246]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [2012.0083 CTS, 18:399]; Center in Nano Science and Nano technology at LiTH (CeNano) at Linkoping University

Background: TiO2 nanoparticles (TiO2 NPs) are the nanomaterial most produced as an ultraviolet (UV) filter. However, TiO2 is a semiconductor and, in nanoparticle size, is a strong photocatalyst, raising concerns about photomutagenesis. Mesoporous silica nanoparticles (MSN) were synthetized incorporating TiO2 NPs (TiO2@MSN) to develop a cosmetic UV filter. The aim of this study was to assess the toxicity of TiO2@MSN, compared with bare MSN and commercial TiO2 NPs, based on several biomarkers. Materials and Methods: Human peripheral blood mononuclear cells (PBMC) were exposed to TiO2@MSN, bare MSN (network) or commercial TiO2 NPs for comparison. Exposed PBMC were characterized for cell viability/apoptosis, reactive oxygen species (ROS), nuclear morphology, and cytokines secretion. Results: All the nanoparticles induced apoptosis, but only TiO2 NPs (alone or assembled into MSN) led to ROS and micronuclei. However, TiO2@MSN showed lower ROS and cytotoxicity with respect to the P25. Exposure to TiO2@MSN induced Th2-skewed and pro-fibrotic responses. Conclusions: Geno-cytotoxicity data indicate that TiO2@MSN are safer than P25 and MSN. Cytokine responses induced by TiO2@MSN are imputable to both the TiO2 NPs and MSN, and, therefore, considered of low immunotoxicological relevance. This analytical assessment might provide hints for NPs modification and deep purification to reduce the risk of health effects in the settings of their large-scale manufacturing and everyday usage by consumers.

Background Together with poor biodegradability and insufficient recycling, the massive production and use of plastics have led to widespread environmental contamination by nano- and microplastics. These particles accumulate across ecosystems - even in the most remote habitats - and are transferred through food chains, leading to inevitable human ingestion, that adds to the highest one due to food processes and packaging. Objective The present review aimed at providing a comprehensive overview of current knowledge regarding the effects of nano- and microplastics on intestinal homeostasis. Methods We conducted a literature search focused on the in vivo effects of nano- and microplastics on gut epithelium and microbiota, as well as on immune response. Results Numerous animal studies have shown that exposure to nano- and microplastics leads to impairments in oxidative and inflammatory intestinal balance, and disruption of the gut’s epithelial permeability. Other notable effects of nano- and microplastic exposure include dysbiosis (changes in the gut microbiota) and immune cell toxicity. Moreover, microplastics contain additives, adsorb contaminants, and may promote the growth of bacterial pathogens on their surfaces: they are potential carriers of intestinal toxicants and pathogens that can potentially lead to further adverse effects. Conclusion Despite the scarcity of reports directly relevant to human, this review brings together a growing body of evidence showing that nano- and microplastic exposure disturbs the gut microbiota and critical intestinal functions. Such effects may promote the development of chronic immune disorders. Further investigation of this threat to human health is warranted. 17;1

Graphical abstract, Highlights • 5-Hydroxymethylfurfural induced anaphylactoid reactions on ICR mice and BN rats model. • 5-Hydroxymethylfurfural induced degranulation of RBL-2H3 cells and P815 cells. • 5-Hydroxymethylfurfural induces anaphylactoid reactions both in vivo and in vitro. • 5-Hydroxymethylfurfural limits in related products should receive more regulatory attention., Aim Excessive exposure to 5-hydroxymethylfurfural (5-HMF), which is a common impurity in various sugar-containing products, induces serious side effects. Our previous study revealed that 5-HMF exerted immune sensitizing potential when injected into rodents. In this study, we explored 5-HMF mediated anaphylactoid reactions and its underlying molecular mechanisms. Methods We investigated anaphylactoid reactions in Brown Norway (BN) rats and Institute of Cancer Research (ICR) mice to identify 5-HMF mediated in vivo anaphylactoid reactions. RBL-2H3 and P815 cell degranulation models were also established, and degranulation, enzyme-linked immunosorbent, filamentous actin (F-actin) microfilament staining, and western blot assays were performed in these cells. Results We showed that 5-HMF induced anaphylactoid reactions by increasing blood vessel permeability in mice, and significantly elevating histamine (His) and glutathione peroxidase-1 (Gpx-1) levels in rat serum. Moreover, after incubation with 5-HMF, β-hexosaminidase (β-Hex), His, IL-4 and IL-6 levels were all significantly increased, thereby inducing cellular degranulation in RBL-2H3 and P815 cells. Finally, 5-HMF also upregulated Lyn, Syk, p38 and JNK protein phosphorylation levels. Conclusions Our findings suggest that 5-HMF induces anaphylactoid reactions both in vivo and in vitro, therefore 5-HMF limits in sugar-containing products should receive more regulatory attention.

Objective Perfluorooctanoic acid (PFOA) is a ubiquitous environmental contaminant and a known immune suppressant in humans and experimental animal models. Studies on PFOA have focused on suppression of the adaptive immune response; however, little is known of the impact on innate immunity, especially during embryogenesis. Therefore, we utilized the zebrafish chemotaxis assay coupled with in situ hybridization for myeloperoxidase expression to determine the effects of PFOA exposure on neutrophil migration in the developing zebrafish embryo. Zebrafish embryos are a well-established in vivo model that exhibit high homology with the development of human innate immunity. Results Treatment of zebrafish with increasing concentrations of PFOA identified the lethal concentration in 50% of the embryos (LC50) to be 300 mg/L. Utilizing the zebrafish chemotaxis assay, this study showed that wounding induced significant neutrophil migration to the site of injury, and that neutrophil number in the wound region was significantly reduced in response to 48-h PFOA exposure (well below doses causing acute mortality). This study demonstrates that the developing embryo is sensitive to PFOA exposure and that PFOA can modify the innate immune system during embryonic development. These results lay the groundwork for future investigation on the mechanisms underlying PFOA-induced developmental immunotoxicity.

Clinical use of CuO nanoparticles (NPs) as antibacterials can be hampered by their toxicity to human cells. We hypothesized that certain surface functionalizations of CuO NPs may render NPs toxic to bacteria, but still be relatively harmless to human cells. To control this hypothesis, the toxicity of differently functionalized CuO NPs to bacteria Escherichia coli vs human cells (THP-1 macrophages and HACAT keratinocytes) was compared using similar conditions and end points. CuO NPs functionalized with polyethylene glycol (CuO–PEG), carboxyl (CuO–COOH, anionic), ammonium (CuO–NH4+, cationic) and unfunctionalized CuO NPs and CuSO4 (controls) were tested. In general, the toxicity of Cu compounds decreased in the following order: CuO–NH4+ > unfunctionalized CuO > CuSO4 > CuO–COOH > CuO–PEG. Positively charged unfunctionalized CuO and especially CuO–NH4+ proved most toxic (24-h EC50 = 21.7–47 mg/l) and had comparable toxicity to bacterial and mammalian cells. The multivariate analysis revealed that toxicity of these NPs was mostly attributed to their positive zeta potential, small hydrodynamic size, high Cu dissolution, and induction of reactive oxygen species (ROS) and TNF-α. In contrast, CuO–COOH and CuO–PEG NPs had lower toxicity to human cells compared to bacteria despite efficient uptake of these NPs by human cells. In addition, these NPs did not induce TNF-α and ROS. Thus, by varying the NP functionalization and Cu form (soluble salt vs NPs), it was possible to “target” the toxicity of Cu compounds, whereas carboxylation and PEGylation rendered CuO NPs that were more toxic to bacteria than to human cells envisaging their use in medical antibacterial products.

Significant advances in immunotherapies have resulted in the increasing need of predictive preclinical models to improve immunotherapeutic drug development, treatment combination, and to prevent or minimize toxicity in clinical trials. Immunodeficient mice reconstituted with human immune system (HIS), termed humanized mice or HIS mice, permit detailed analysis of human immune biology, development, and function. Although this model constitutes a great translational model, some aspects need to be improved as the incomplete engraftment of immune cells, graft versus host disease and the lack of human cytokines and growth factors. In this review, we discuss current HIS platforms, their pathology, and recent advances in their development to improve the quality of human immune cell reconstitution. We also highlight new technologies that can be used to better understand these models and how improved characterization is needed for their application in immuno-oncology safety, efficacy, and new modalities therapy development.

Graphene, known as "black gold", has important applications in various fields. In previous studies, it has been proved that graphene oxide (GO) which is a derivative of graphene has low toxicity. However, the immunotoxicity of GO has not been fully elucidated. In this work, we used DC2.4 cell line to investigate the in vitro immunotoxicity of two types of GO, mono-layer GO (mono-GO) and multi-layer GO (multi- GO). We found that mono-GO had less effect on cell viability than multi-GO, but both mono-GO and multi-GO significantly induced the generation of ROS in DC2.4 cells. Interestingly, mono-GO caused DC2.4 cells to aggregate, thus changed the cell morphology significantly. However, no similar influence occurred for multi-GO. In addition, the results showed that these two GOs obviously enhance the release of TNF-α by DC2.4 cells with and without LPS stimulation. GO did not affect the level of IL-6 released from DC2.4 cells, but multi-GO promoted the release of IL-6 while mono-GO inhibited the production of IL-6 when cells were in response to LPS stimulation. Whole-transcriptome sequencing analysis found some immune-related differentially expressed genes including H2-DMb1, Ncbp3, Oas2, Men1, Fas, Cd320, Cd244, and Tinagl1 which are engaged in the immune system process. These results suggested that both mono-GO and multi-GO are immunotoxic to DC2.4 cells, which provides important basis for subsequent biological and clinical medical applications.

Prenatal particle exposure has been shown to increase allergic responses in offspring. Carbon nanotubes (CNTs) possess immunomodulatory properties, but it is unknown whether maternal exposure to CNTs interferes with offspring immune development. Here, C57Bl/6J female mice were intratracheally instilled with 67 of μg multiwalled CNTs on the day prior to mating. After weaning, tolerance and allergy responses were assessed in the offspring. Offspring of CNT-exposed (CNT offspring) and of sham-exposed dams (CTRL offspring) were intranasally exposed to ovalbumin (OVA) once weekly for 5 weeks to induce airway mucosal tolerance. Subsequent OVA sensitization and aerosol inhalation caused low or no OVA-specific IgE production and no inflammation. However, the CNT offspring presented with significantly lower OVA-specific IgG1 levels than CTRL offspring. In other groups of 5-week-old offspring, low-dose sensitization with OVA and subsequent OVA aerosol inhalation led to significantly lower OVA-specific IgG1 production in CNT compared to CTRL offspring. OVA-specific IgE and airway inflammation were non-significantly reduced in CNT offspring. The immunomodulatory effects of pre-gestational exposure to multiwalled CNTs were unexpected, but very consistent. The observations of suppressed antigen-specific IgG1 production may be of importance for infection or vaccination responses and warrant further investigation.

Microcystins (MCs) are produced by certain bloom-forming cyanobacteria that can induce toxicity in various organs, including renal toxicity, reproductive toxicity, cardiotoxicity, and immunosuppressive effects. It has been a significant global environmental issue due to its harm to the aquatic environment and human health. Numerous investigators have demonstrated that MC exposure can induce a widespread epidemic of enterogastritis with symptoms similar to food poisoning in areas close to lakes. Both in vivo and in vitro studies have provided evidence of positive associations between MC exposure and gastrointestinal toxicity. The toxicity of MCs on the gastrointestinal tract is multidimensional. MCs can affect gastrointestinal barrier function and shift the structure of gut microbiota in different gut regions. Furthermore, MCs can inhibit the secretion of gastrointestinal digestive enzymes and the release of inflammatory cytokines, which affects the expression of immune-related genes in the intestine. The damage of the intestine is closely correlated to MC exposure because the intestine is the main site for the digestion and absorption of nutrients. The damage to the gastrointestinal tract due to MCs was summarized from different aspects, which can be used as a foundation for further exploration of molecular damage mechanisms.

Elevated levels of lead have been found in waterfowl, due to human activities. Lead may cause immunomodulatory effects, but the mechanisms are largely unknown, especially after viral challenges. To characterize avian immunomodulatory hazards of lead (Pb)2+, we used chicken macrophage (HD‐11) and B‐lymphocyte (DT40) cell lines, as in vitro models for the innate and adaptive immune systems, respectively. The cells were activated via toll‐like receptor‐3 by polyinosinic–polycytidylic acid sodium salt (poly I:C), mimicking viral infections. Our results indicate that Pb2+ is cytotoxic to both cell lines, macrophages being more sensitive. De novo synthesis of glutathione plays an important role in protecting macrophages from Pb2+ intoxication, which might also be closely involved in the induction of nitric oxide after Pb2+ exposure. Stimulatory effects on cell proliferation were noticed at noncytotoxic Pb2+ concentrations as well. Exposure to Pb2+ could also affect the inflammatory status by inhibiting the pro‐inflammatory interferon (IFN)‐γ while promoting the production of anti‐inflammatory type I IFNs in both macrophages and B‐cells, and increasing intracellular IgM levels in B‐cells. These results suggest that the immunomodulatory effects of Pb2+ in birds are probably closely associated with disruption of immune cell proliferation and cytokine production, potentially causing disorders of the avian immune system. Environ Toxicol Chem 2020;39:1060–1070. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC

Bisphenols are widely used in the synthesis of polycarbonate plastics, epoxy resins, and thermal paper, which are used in manufacturing items of daily use. Packaged foods and drinks are the main sources of exposure to bisphenols. These chemicals affect humans and animals by disrupting the estrogen, androgen, progesterone, thyroid, and aryl hydrocarbon receptor functions. Bisphenols exert numerous harmful effects because of their interaction with receptors, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial dysfunction, and cell signal alterations. Both cohort and case-control studies have determined an association between bisphenol exposure and increased risk of cardiovascular diseases, neurological disorders, reproductive abnormalities, obesity, and diabetes. Prenatal exposure to bisphenols results in developmental disorders in animals. These chemicals also affect the immune cells and play a significant role in initiating the inflammatory response. Exposure to bisphenols exhibit age, gender, and dose-dependent effects. Even at low concentrations, bisphenols exert toxicity, and hence deserve a critical assessment of their uses. Since bisphenols have a global influence on human health, the need to discover the underlying pathways involved in all disease conditions is essential. Furthermore, it is important to promote the use of alternatives for bisphenols, thereby restricting their uses.

Background Xenogeneic bone has been widely used in a variety of clinical bone-related disease to promote bone healing and restore bone defects. However, the adverse effects of immune system limit its application in the clinic. The aim of this study was to evaluate xenogeneic bone safety of immunotoxicity and explore the methods for immune risk supervision. Results Xenogeneic bone, which is freeze-dried bovine cancellous bone, was implanted into the muscle of mice. On day 7, 14 and 28, the effects of xenogeneic bone were examined on humoral immunity and cellular immunity, including the levels of IgG, IgM, C3, inflammatory factors (TNF-α, IL-6), alkaline phosphatase (ALP) and the lymphocyte phenotype. The data showed that xenogeneic bone implantation had no potential to induce immune responses not only in humoral immunity but also in cellular immunity. To reveal the risk of immunogenicity, the residual DNA and the clearance of α-gal epitope were analyzed in 2 different bones (bone 1 is deproteinized bone, bone 2 is acellular and defatted bone). It was suggested that DNA of xenogeneic bone can be limited to Conclusions Through the detection of xenogeneic bone immunotoxicity, our findings indicated that the supervisions of risk factors could contribute to reduce the immune risk. And the risk factors under the acceptable limitation could decrease or replace animal experiment. However, it still needs to be studied on the limitation of α-gal epitope to predict rejection of xenogeneic bone more accurately.

Innate immunity can be triggered by the presence of microbial antigens and other contaminants inadvertently introduced during the manufacture and purification of bionanopharmaceutical products. Activation of these innate immune responses, including cytokine secretion, complement, and immune cell activation, can result in unexpected and undesirable host immune responses. These innate modulators can also potentially stimulate the activation of adaptive immune responses, including the formation of anti-drug antibodies which can impact drug effectiveness. To prevent induction of these adverse responses, it is important to detect and quantify levels of these innate immunity modulating impurities (IIMIs) that may be present in drug products. However, while it is universally agreed that removal of IIMIs from drug products is crucial for patient safety and to prevent long-term immunogenicity, there is no single assay capable of directly detecting all potential IIMIs or indirectly quantifying downstream biomarkers. Additionally, there is a lack of agreement as to which of the many analytical assays currently employed should be standardized for general IIMI screening. Herein, we review the available literature to highlight cellular and molecular mechanisms underlying IIMI-mediated inflammation and its relevance to the safety and efficacy of pharmaceutical products. We further discuss methodologies used for direct and indirect IIMI identification and quantification.

The Freshwater ecosystem of India supports a wide range of invertebrates including Eunapius carteri, a common variety of sponge. Copper oxide nanoparticles and copper sulfate are less studied industrial toxins which accumulate in natural waterbodies and affect the physiology of sponge. Flagellary mode of feeding and porous architecture facilitate the entry of these contaminants into the body of the sponge. Current experimental endpoints included phagocytic response, lysosomal membrane stability, generation of reactive oxygen species, superoxide anion, nitric oxide and activities of phosphatases, lysozyme, phenoloxidase, superoxide dismutase, catalase and glutathione-S-transferase in E. carteri exposed separately to these toxins for 7 and 14 days. Treatment with both toxins for 14 d resulted in inhibition in phagocytosis, pro and antioxidation defense response of sponge. Copper oxide nanoparticle exposure led to an increase in generation of reactive oxygen species. Both the toxins depleted lysosomal membrane stability and activities of lysozyme and phosphatases. Unrestricted contamination of freshwater ecosystem by copper oxide nanoparticles and copper sulfate may lead to a state of physiological stress and immunocompromisation in E. carteri, a neglected aquatic bioresource of India. Selected experimental endpoints may be considered as biomarkers of aquatic toxicity of copper oxide nanoparticles and copper sulfate.