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There is a continuing interest in whether Bisphenol A (BPA) is able to cause adverse health effects through interaction with elements of the immune system. That interest has been fuelled further by the recent publication of a draft opinion on BPA prepared by the European Food Safety Authority (EFSA) Panel on Food Contact Materials, Enzymes and Processing Aids (CEP). This draft opinion judged effects on the immune system to be the most sensitive health outcome, and identified BPA-induced changes in the frequency of T-helper (TH)-17 cells in the spleens of mice as being the critical effect based on an association of these cells with inflammation. Based on these evaluations the CEP Panel recommended that a revised Tolerable Daily Intake (TDI) for BPA of 0.04 ng/kg bw/day should be adopted; representing a very substantial reduction (100,000-fold) compared with the existing TDI. The purpose of this commentary is to summarize briefly the role of TH17 cells in immune responses, and to review relevant literature regarding the influence of BPA on these cells, and on inflammatory responses in the lung and respiratory allergy. The conclusion drawn is that based on uncertainties about the effects of BPA on TH17 cells and lung inflammation in mice, the absence of consistent or persuasive evidence from human studies that exposure of BPA is associated with inflammation or allergy, and unresolved questions regarding the species selectivity of immune effects induced by BPA, it is inappropriate to adopt the revised TDI. Additional research is required to explore further the influence of BPA on the immune system and immune responses. [ABSTRACT FROM AUTHOR]

Increased expectations from a number of regulatory agencies, e.g., Environmental Protection Agency (EPA), Food and Drug Administration (FDA), European Medicines Agency (EMEA), and the Ministry of Health, Labour and Welfare (MHLW) of Japan, call for the evaluation of potential adverse effects on the immune system. As recently summarized in the ICH S8 guideline, the T-cell-dependent antibody response (TDAR) has been identified in a regulatory context as a main functional test of immunotoxicity. While the characterization of immunotoxic potential is pertinent to both the chemical and pharmaceutical industries, the use of immunotoxicology data for hazard identification and/or risk assessment in each case is different. Therefore, multiple approaches to immunotoxicity testing have evolved. The assays that evaluate TDAR function include both well-established tests, e.g., anti-sheep red blood cell plaque-forming cell (PFC) assay, and newer models, e.g., anti-keyhole limpet hemocyanin (KLH) antibody ELISA. These tests vary in the study design, antigen application and analytical methods. However, they all evaluate the same endpoint - a competent immune (e.g., antibody) response to an antigen. Numerous issues have been identified in the application of TDAR tests, including high animal to animal variability; differences in antigen source and potency; a lack of established "normal range" of the immune response and uncertainty about the degree of inhibition of the TDAR to be considered toxicologically important. As such, the need for a forum to discuss these issues was recognized by the immunotoxicology community, and was addressed at the 2006 Society of Toxicology (SOT) Workshop. A series of papers will summarize that forum with the ultimate objectives being to build a consensus among immunotoxicologists on the implications of these factors on using TDAR results in hazard identification and/or risk assessment, and to establish a criteria to classify compounds as immunotoxicants. [ABSTRACT FROM AUTHOR]

The immunotoxic potential of drug candidates is assessed through the examination of results from a variety of studies and endpoints. While the functional assessment of CD8+ cytotoxic T-lymphocytes (CTL) is well-characterized in the clinic, the lack of a robust macaque CTL functional assay has been an important hurdle in evaluating and accurately quantifying cell-mediated CD8+ T-cell effector responses in the nonclinical setting. This paper describes the development of an assay to measure CTL activity in peripheral blood mononuclear cells (PBMC) isolated from Cynomolgus macaques. A human EGFR/CD3 Bispecific T-cell Engager (BiTE®) was used to mount a robust CD8+ T-cell response in the presence of target-expressing cells. Upon target engagement, degranulation of CD107a and production of interferon (IFN)-γ both reliably indicated a robust functional response in CD8+ T-cells. The BiTE®-mediated stimulation method proved to be favorable when compared to other methods of stimulation in the absence of target cells. These studies demonstrated acceptable longitudinal variability of the functional assay and sensitivity to dexamethasone-mediated immunosuppression. Taken together, the results indicated an assay leveraging CD3-bispecific antibodies and target-expressing cells can provide a robust approach to the in vitro or ex vivo assessment of CTL function in Cynomolgus macaques. Because the impairment of CTL activity by immunomodulators is recognized to be an important contributor to decreased antiviral defense and increased carcinogenicity risk, we believe that this novel assay to be a valuable addition to the immunotoxicology assessment of therapeutic drug candidates. [ABSTRACT FROM AUTHOR]

Vanadium (V) is a transition metal found in air adsorbed onto suspended particles. As a result, urban populations are often exposed to this element as a constituent of particulate matter (PM). One aspect of the myriad toxicities that might arise from these exposures is altered immune responses. Previous reports from the laboratory reported modifications in splenic architecture - with germinal center hyperplasia and a suppressed humoral immune response - in mice that had been exposed to vanadium agents via inhalation. This paper reports a decrease in the presence of the CD11c surface marker on mouse thymic dendritic cells (DC) as a result of host exposure to vanadium (here, in the form of vanadium pentoxide; V2O5) over a period of 4 weeks. All results were obtained using immunohistochemistry and flow cytometry. It is surmised that this decrease might induce a dysfunction, including possible negative selection of T-cells, which could increase the presence of autoreactive clones in the exposed host. Such an outcome could, in turn, increase the risk for development of autoimmune reactions in different organs specifically, and of autoimmune diseases in general in these V-exposed hosts. [ABSTRACT FROM AUTHOR]

The intestinal environment is considered to play an important role both in colorectal tumor development and in the evolution and modulation of mucosal immunity. Studies in animals reared in germ-free (GF, without any intestinal microflora) versus conventional (CV, with regular microflora in bowel) conditions can aid in clarifying the influence of bacteria on carcinogenesis and anti-cancer immune responses in situ. The lower incidence of colon cancers and better immunological parameters in GF animals versus CV ones after chemically-induced carcinogenesis raises questions about specific characteristics of the immunological networks in each respective condition. Different levels of tolerance/regulatory mechanisms in the GF versus CV animals may influence the development of immune responses not only at the level of mucosal, but also at the systemic, immunity. We hypothesize that GF animals can better recognize and respond to evolving neoplasias in the bowel as a consequence of their less-tolerogenic immunity (i.e., due to their more limited exposure to antigens to become tolerated against at the intestinal level). In this paper, we review the role of bacteria in modulating gut environment and mucosal immunity, their importance in cancer development, and aspects of immune regulation (both at local and systemic level) that can be modified by bacterial microflora. Lastly, the use of GF animals in comparison with conventionally-raised animals is proposed as a suitable and potent model for understanding the inflammatory network and its effect on cancer immunity especially during colorectal cancer development. [ABSTRACT FROM AUTHOR]

Micro- and nanoplastics (MNP) are ubiquitously present in the environment due to their high persistence and bioaccumulative properties. Humans get exposed to MNP via various routes and consequently, they will encounter dendritic cells (DC) which are antigen-presenting cells involved in regulating immune responses. The consequences of DC exposure to MNP are an important, yet understudied, cause of concern. Therefore, this study aimed to assess the uptake and effect of MNP in vitro by exposing human monocyte-derived dendritic cells (MoDC) to virgin and environmentally weathered polystyrene (PS) particles of different sizes (0.2, 1, and 10 µm), at different concentrations ranging from 1 to 100 µg/ml. The effects of these particles were examined by measuring co-stimulatory surface marker (i.e. CD83 and CD86) expression. In addition, T-cell proliferation was measured via a mixed-leukocyte reaction (MLR) assay. The results showed that MoDC were capable of absorbing PS particles, and this was facilitated by pre-incubation in heat-inactivated (HI) plasma. Furthermore, depending on their size, weathered PS particles in particular caused increased expression of CD83 and CD86 on MoDC. Lastly, weathered 0.2 µm PS particles were able to functionally activate MoDC, leading to an increase in T-cell activation. These in vitro data suggest that, depending on their size, weathered PS particles might act as an immunostimulating adjuvant, possibly leading to T-cell sensitization. [ABSTRACT FROM AUTHOR]

Biotherapeutic monoclonal antibodies (mAb) play important roles in clinical medicine but their potential to elicit immune responses in patients remains a major issue. In a study designed to investigate the effect of aggregation on immunogenic responses, mice were immunized with two monoclonal antibodies (mAb1 and mAb2). Serum levels of total IgG, IgG1, and IgG2a were measured by ELISA. An anti-mouse IgG2a monoclonal detection antibody cross-reacted with mAb2 but not mAb1, leading to high background when the ELISA plate was coated with mAb2. The problem was solved by use of a goat anti-mouse IgG2a polyclonal antibody that demonstrated the required specificity. IgG2a responses were similar for monomer- or aggregate-coated ELISA plates. The results demonstrate the importance of assessment of the specificity of individual reagents when measuring antibody responses against therapeutic antibodies by ELISA. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The prevalence of iron (Fe) deficiency and subclinical lead (Pb) toxicity is high in developing countries like India, and information on their potential additive effects on immune responses is scant. The current study assessed immune parameters in dual Pb-exposed\Fe-deficient weanling SD rats. Rats were fed a control (CD) or Fe-deficient (ID) diet for 4 weeks and then evaluated for hemoglobin (Hb) and serum Fe status. Then, half the rats in each group began to receive daily oral Pb exposure (25 mg/4 ml/kg BW; gavage) or vehicle for a further 4 weeks (while maintained on original respective diets). After the 4-weeks of dosing, rats were assessed for Hb and serum Fe, and for blood lead level (BLL) and δ-aminolevulinic acid dehydratase (ALAD) activity. At this point, half the rats in each group (now n = 8) were then vaccinated with tetanus toxoid (TT), and then two boosters at 2-week intervals. All the time, rats stayed on their original respective diets along with exposure to Pb on alternate days. At 2 weeks after the final booster, rats were euthanized and blood collected to assess total/specific IgG and IgM levels; mucosal (intestinal) IgA levels were also determined. Spleens were taken to assess CD4+ and CD8+ cell levels and for ex vivo measures of splenocyte proliferation/TH1 and TH2 cytokine formation. The results indicated significant lowering of Hb and serum Fe levels in ID rats and increased blood Pb and decreased ALAD activity in all Pb-exposed rats. Fe-deficiency alone induced significant increases in ALAD activity, but only in an absence of Pb. While there was no impact of any regimen on total or TT-specific IgG, significant decreases in mucosal IgA and TT-specific IgM were seen in ID-fed Pb-exposed rats. CD4+ cell levels were not impacted by treatment; CD8+ levels were increased in all ID/Pb-exposed rats. Ex-vivo splenocyte proliferation was significantly higher among vaccinated rats, as well as ID-fed Pb-exposed unvaccinated rats. Cytokine formation in all cases was highly variable. The results suggest that Fe deficiency compromised cell-mediated, mucosal, and/or humoral immune response-related endpoints and that Pb exposure during the deficiency further impacted these outcomes. [ABSTRACT FROM AUTHOR]

With the rapid development of synthetic alternatives to mineral fibers, their possible effects on the environment and human health have become recognized as important issues worldwide. This study investigated effects of four fibrous materials, i.e. nanofibrillar/nanocrystalline celluloses (NCF and CNC), single-walled carbon nanotubes (CNTs), and crocidolite asbestos (ASB), on pulmonary inflammation and immune responses found in the lungs, as well as the effects on spleen and peripheral blood immune cell subsets. BALB/c mice were given NCF, CNC, CNT, and ASB on Day 1 by oropharyngeal aspiration. At 14 days post-exposure, the animals were evaluated. Total cell number, mononuclear phagocytes, polymorphonuclear leukocytes, lymphocytes, and LDH levels were significantly increased in ASB and CNT-exposed mice. Expression of cytokines and chemokines in bronchoalveolar lavage (BAL) was quite different in mice exposed to four particle types, as well as expression of antigen presentation-related surface proteins on BAL cells. The results revealed that pulmonary exposure to fibrous materials led to discrete local immune cell polarization patterns with a TH2-like response caused by ASB and TH1-like immune reaction to NCF, while CNT and CNC caused non-classical or non-uniform responses. These alterations in immune response following pulmonary exposure should be taken into account when testing the applicability of new nanosized materials with fibrous morphology. [ABSTRACT FROM AUTHOR]

Vanadium is an air pollutant that imparts immunosuppressive effects on NK cell immune responses, in part, by dysregulating interleukin (IL)-2/IL-2R-mediated JAK signaling pathways and inducing apoptosis. The aim of the present study was to evaluate effects of vanadium pentoxide (V2O5) on other IL-2 receptor-mediated signaling pathways, i.e. PI3K-AKT-mTOR and Ras-MAPK. Here, IL-2-independent NK-92MI cells were exposed to different V2O5 doses for 24 h periods. Expression of PI3K, Akt, mTOR, ERK1/2, MEK1, PTEN, SHP1, BAD and phosphorylated forms, as well as caspases-3, -8, -9, BAX and BAK in/on the cells were then determined by flow cytometry. The results show that V2O5 was cytotoxic to NK cells in a dose-related manner. Exposure increased BAD and pBAD expression and decreased that of BAK and BAX, but cell death was not related to caspase activation. At 400 µM V2O5, expression of PI3K-p85 regulatory subunit increased 20% and pPI3K 50%, while that of the non-pPI3K 110α catalytic subunit decreased by 20%. At 200 μM, V2O5 showed significant decrease in non-pAkt expression (p < 0.05); the decrease in pAkt expression was significant at 100 μM. Non-pmTOR expression displayed a significant downward trend beginning at 100 μM. Expressions of pMEK-1/2 and pERK-1/2 increased substantially at 200 μM V2O5. No differences were found with non-phosphorylated ERK-1/2. PTEN expression increased significantly at 100 μM V2O5 exposure whereas pPTEN decreased by 18% at 25 μM V2O5 concentrations, but remained unchanged thereafter. Lastly, V2O5 at all doses decreased SHP1 expression and increased expression of its phosphorylated form. These results indicated a toxic effect of V2O5 on NK cells that was due in part to dysregulation of signaling pathways mediated by IL-2 via increased PTEN and decreased SHP1 expression. These results can help to explain some of the known deleterious effects of this particular form of vanadium on innate immune responses. [ABSTRACT FROM AUTHOR]

Behçet’s disease (BD) is a chronic autoimmune condition primarily prevalent in populations along the Mediterranean Sea. The exact etiology of BD has not been fully explained yet, but the disease occurrence is associated with a genetic factor, human leukocyte antigen (HLA)-B51 antigen. Among the various immunodysfunctions that are found in BD, patients are increased neutrophil motility and superoxide production, as well as elevated production of tumor necrosis factor (TNF)-α and decreased production of interleukin (IL)-10. Elevated levels of inflammatory cytokines like IL-1 and IL-17 in BD have been found associated with aberrant expression of microRNA. Gene polymorphisms in BD patients have been observed in molecules involved in responses to pathogens that can ultimately modulate the host antimicrobial response. Moreover, several single nucleotide polymorphisms (SNPs) have been reported in genes encoding chemokines and adhesion molecules; many of these changes manifest as increases in vascular inflammation and vascular damage. Lastly, genetic and epigenetic changes have been suggested as involved in the pathogenesis of BD. Modifications in DNA methylation have been found in BD patient monocytes and lymphocytes, leading to adverse function of these cells. This review presents a comprehensive compilation of the literature with regard to the immunodysfunction underlying BD, as well as of the genetics, newly described clinical specifications and novel treatment strategies using immunomodulants based on the current understanding of BD. [ABSTRACT FROM PUBLISHER]

High contamination by aflatoxin B1(AFB1) has been detected in Beja province (Tunisia) in many dairy products and animal feed, which has resulted in many tons of cereals and cereals being removed from the market, causing economic loss. While removal represents a means of reducing risk, exposures still occur. Studies have increasingly focused on means of AFB1biodegradation/elimination using lactic acid bacteria and clay mineral. In the study here,Lactobacillus paracaseiBEJ01 (LP) and montmorilonite clay (MT) were used to reduce the physio-/immunotoxicologic disorders that could develop in rats that underwent AFB1exposures for a total of 7 consecutive days. The results indicated that rats treated with AFB1(80 μg/kg BW) alone had significant decreases in lymphocytes in their blood (including B-lymphocytes, CD3+, CD4+, and CD8+T-lymphocyte subtypes, and NK cells), immunoglobulins (IgA and IgG) and pro-inflammatory cytokines; these rats also had altered oxidative stress status. In contrast, in rats treated with LP + MT (2 × 109 cfu/ml [∼ 2 mg/kg] + 0.5 mg MT/kg BW) for a total of 7 days before, concurrent with or after AFB1treatment, there was a significant blockade/mitigation of each AFB1-impacted parameter. Moreover, treatment with the mixture at any point in relation to AFB1treatment expectedly caused enhanced TNFαand IL-1βexpression relative to control values; all other parameters were comparable to values noted in control rats. Alone, the mixture had no impact on host parameters. From the results here it may be concluded the the LP + MT mixture was effective in protecting these hosts against AFB1-induced immunologic/physiologic disorders and that LP + MT could prevent and/or mitigate AFB1toxicitiesin vivo. [ABSTRACT FROM AUTHOR]

Aluminum oxide nanoparticles (AlO NP) have been widely utilized in a variety of areas, including in the optical, biomedical and electronic fields and in the overall development of nanotechnologies. However, their toxicological profiles are still not fully developed. This study compared the distribution and immunotoxicity of two rod-types of AlO NP. As reported previously, the two types of AlO NP had different aspect ratios (long-type: 6.2 ± 0.6, short-type: 2.1 ± 0.4), but the size and surface charge were very similar. On Day 14 after a single intravenous (IV) injection (1.25 or 5 mg/kg), both AlO NP accumulated primarily in the liver and spleen and altered the levels of redox response-related elements. The accumulated level was higher in mice exposed to the long-type AlO NP compared to the short-type. Additionally, it was noted that the levels of IL-1β, IL-8 and MCP-1 were enhanced in the blood of mice exposed to both types of AlO NP and the percentages of neutrophils and monocytes among all white blood cells were increased only in mice injected with the long-type AlO NP (5 mg/kg). In addition, as compared to the control, co-expression of CD80 and CD86 (necessary for antigen presentation) on splenocytes together with a decreased expression of chemotaxis-related marker (CD195) was attenuated by exposure to the AlO NP, especially the long-type. Taken together, the data suggest that accumulation following a single IV injection with rod-types of AlO NP is strengthened by a high aspect ratio and, subsequently, this accumulation has the potential to influence immune functions in an exposed host. [ABSTRACT FROM AUTHOR]

Cytokines are considered important factors in the modulation of various immune responses. Among them, interleukin (IL)-21 is one of the major immune modulators, adjusting various immune responses by affecting various immune cells. It has been suggested that IL-21 may enhance autoimmunity through different mechanisms, such as development and activation of helper T (TH)-17 and follicular helper T (TFH) cells, activation of natural killer (NK) cells, enhancing B-cell differentiation and antibody secretion and suppression of regulatory T (Treg) cells. Moreover, IL-21 has also been suggested to be an inducer of autoimmunity when following treatment of MS patients with some therapeutics such as alemtuzumab. This review will seek to clarify the precise role of IL-21/IL-21R in the pathogenesis of MS and, in its animal model, experimental autoimmune encephalomyelitis (EAE). [ABSTRACT FROM PUBLISHER]

Recent studies suggest that exposure to perfluorinated alkylate substances (PFASs) may induce immunosuppression in humans and animal models. In this exploratory study, 12 healthy adult volunteers were recruited. With each subject, serum-PFAS concentrations were measured and their antibody responses prospectively followed for 30 days after a booster vaccination with diphtheria and tetanus. The results indicated that serum-PFAS concentrations were positively correlated and positively associated with age and male sex. The specific antibody concentrations in serum were increased from Day 4 to Day 10 post-booster, after which a constant concentration was reached. Serum PFAS concentrations showed significant negative associations with the rate of increase in the antibody responses. Interestingly, this effect was particularly strong for the longer-chain PFASs. All significant associations remained significant after adjustment for sex and age. Although the study involved a small number of subjects, these findings of a PFAS-associated reduction of the early humoral immune response to booster vaccination in healthy adults supported previous findings of PFAS immunosuppression in larger cohorts. Furthermore, the results suggested that cellular mechanisms right after antigen exposure should be investigated more closely to identify possible mechanisms of immunosuppression from PFAS. [ABSTRACT FROM AUTHOR]

Leishmaniasis is one of the most common infectious diseases transmitted by an obligate intracellular genusLeishmania. As there is no efficient vaccination strategy for leishmaniasis, new immunostimulatory components may enhance protective immune responses against this parasite. Lipophosphoglycan 3 (LPG3) is an essential protein required for LPG assembling. In this study, the ability of recombinant LPG3 (rLPG) and its fragments to activate isolated healthy human T-cells and cytokine secretion was evaluatedin vitro. The results showed that rLPG3 and its N-terminal fragment (rNT-LPG3) enhanced expression of CD69 on the surface of T-cells and promoted differentiation of CD4+T-lymphocytes toward a T-helper 1 (TH1) phenotype, in part, through up-regulation of interferon (IFN)-γexpression in a TLR2-independent manner. These results indicated the protective effects of LPG3 (particularly NT-LPG3 fragment) as a potent immunostimulatory component ofleishmaniain vaccination against leishmaniasis. Further investigations inin vivoassays are clearly warranted. [ABSTRACT FROM AUTHOR]

The use of probiotics has gained considerable popularity in the marketplace in the US and has been steadily increasing due to consumer interest in potential treatment of various diseases, which may be due to modulation of immune responses. The aim of this review is to present information from representative studies regarding some of the possible applications and clinical effects of probiotic use in diseases of altered immunoglobulin (IgE) regulation (allergic rhinitis (AR), asthma, atopic dermatitis (AD) and food sensitization). Reports in humans are sparse or controversial; there is currently little reliable scientific data that supports the theory that there exists a cause–effect relationship between taking probiotics and alleviation of allergic disease. Unfortunately, these findings are too variable to allow substantial conclusions as to the efficacy and effectiveness of probiotic use in these disease states. [ABSTRACT FROM AUTHOR]

Tetanus is a highly fatal disease caused by tetanus neurotoxin (TeNT) and remains a major threat to human and animal health, despite preventive strategies. TeNT is composed of heavy and light chain linked by a disulfide bond. The antibody response to TeNT is polyclonal and directed to multiple epitopes within both the light and heavy chains, leading to toxin neutralization. This study was undertaken to localize and compare neutralizing epitopes recognized by human and mouse TeNT-specific antibodies at a clonal level. In the present study, 22 murine hybridoma clones and 50 human lymphoblastoid cell lines secreting monoclonal antibodies (mAb) were generated against TeNT. The specificity of these mAb was determined using different recombinant fragments of tetanus toxin. Moreover, this study investigated thein vitrotoxin neutralizing activity of these mAb by a ganglioside GT1b assay. The results showed that tetanus toxoid immunization in humans and BALB/c mice induced a vigorous humoral immune response against different fragments of TeNT, particularly the carboxyl-terminal fragment of the heavy chain (known as fragment C). The fragment C-specific human and mouse mAb could largely neutralize TeNT. However, while all fragment C-specific human mAb reacted with the carboxyl-terminal part of this fragment (HCC), the majority of the mouse mAb failed to recognize this region. These results suggested that fragment C is the major target for the TeNT neutralizing antibodies, although different epitopes seem to be targeted by human and mouse antibodies. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a class of synthetic compounds that have widespread use in consumer and industrial applications. PFAS are considered environmental pollutants that have various toxic properties, including effects on the immune system. Recent human studies indicate that prenatal exposure to PFAS leads to suppressed immune responses in early childhood. In this study, data from the Norwegian BraMat cohort was used to investigate transcriptomics profiles in neonatal cord blood and their association with maternal PFAS exposure, anti-rubella antibody levels at 3 years of age and the number of common cold episodes until 3 years. Genes associated with PFAS exposure showed enrichment for immunological and developmental functions. The analyses identified a toxicogenomics profile of 52 PFAS exposure-associated genes that were in common with genes associated with rubella titers and/or common cold episodes. This gene set contains several immunomodulatory genes (CYTL1, IL27) as well as other immune-associated genes (e.g.EMR4P, SHC4, ADORA2A). In addition, this study identifiedPPARDas a PFAS toxicogenomics marker. These markers can serve as the basis for further mechanistic or epidemiological studies. This study provides a transcriptomics connection between prenatal PFAS exposure and impaired immune function in early childhood and supports current views on PPAR- and NF-κB-mediated modes of action. The findings add to the available evidence that PFAS exposure is immunotoxic in humans and support regulatory policies to phase out these substances. [ABSTRACT FROM AUTHOR]

BTBR T+tf/J (BTBR) mice were recently cited as a suitable animal model for the study of autism because of their behavioral characteristics and immunological changes similar to those reported from autistic subjects. The BTBR mouse was reported to have significantly higher levels of serum IgG, brain IgG deposits and anti-brain IgG than highly social C57BL/6 mice, suggesting involvement of aberrant immune responses in the occurrence of autism. Up-regulation of IgG production was investigated here, with a focus on the pattern of IgG isotype distribution compared with that in FVB/NJ (FVB) mice, another highly social control strain. The results indicated that levels of serum IgG1, IgG2band IgG3in post-natal day 21 BTBR mice was significantly higher than FVB mice, regardless of sex, resulting in higher IgG1:IgG2aratios in BTBR mice than in FVB mice (statistical significance in males). A similar outcome regarding the IgG1:IgG2aratio was observed in culture supernatants of bone marrow cells from these hosts. A presence of brain-reactive IgG in the sera of BTBR was higher than in FVB mice; levels of brain-reactive IgG against whole brain homogenates were higher in BTBR than in FVB mice, with significant differences seen in the striatum and substantia nigra regions. Levels of IgG1deposited in the cerebellum, cortex, hippocampus or striatum of both BTBR male and female mice were significantly higher than in FVB counterparts. Overall, these results suggest that alterations in IgG isotype production or deposition in the brain could be implicated in the aberrant immune reactivities of BTBR mice. [ABSTRACT FROM PUBLISHER]

The mouse drug allergy model (MDAM) was developed as a tool to predict the potential of systemically administered drugs to produce hypersensitivity reactions (HR). Drugs associated with HR in the clinic produce a marked increase in the cellularity of the draining lymph nodes (DLN) in the MDAM. The objective of this study was to characterize the changes in the DLN following exposure to drugs associated with HR and to investigate whether lymphocyte migration and/or proliferation play a role in the response. These endpoints were also investigated in the local lymph node assay (LLNA) to determine whether responses between the two assays occur via similar mechanisms. Results demonstrated that total numbers of T- and B-cells were proportionally increased in the DLN of mice treated with positive control drugs (i.e. abacavir, amoxicillin, ofloxacin, and sulfamethoxazole) compared to animals administered the vehicle or negative control drugs (metformin and cimetidine). In contrast, a significant increase in the B-cell population of the DLN was observed for 2,4-dinitrofluorobenzene (DNFB) following the LLNA protocol. Down-regulation of CD62L and up-regulation of CCR7 were observed for T-cells from the DLN of the positive control treated mice in the MDAM, but not with DNFB in the LLNA. A mild increase in T-cell proliferation was observed in the MDAM with positive control drugs, while DNFB in the LLNA induced proliferation within the B-cell population only. Anti-CD40L antibody administration inhibited MDAM responses to positive control drugs, but did not affect DNFB-induced increases in total cell number in the LLNA. These results suggest that the increased cellularity of the DLN in the MDAM may be the result of drug-induced alterations in lymphocyte migration and/or effects on lymphocyte proliferation. Moreover, it appears that different mechanisms may be involved in driving the MDAM and LLNA responses. [ABSTRACT FROM PUBLISHER]

Amodiaquine (AQ) has been reported to cause severe idiosyncratic drug-induced liver injury (IDILI) in humans. There is evidence that AQ-induced idiosyncratic drug reactions are immune mediated, but their exact mechanism is not fully understood. AQ is oxidized to a reactive quinoneimine metabolite, and it has been suggested that covalent binding of this metabolite leads to an immune response and liver injury. A valid animal model would greatly facilitate mechanistic studies. This laboratory had previously reported that chronic treatment of C57BL/6 mice with AQ induced a delayed-onset mild liver injury that appeared to resolve with immune tolerance. The current study attempted to prevent immune tolerance by first immunizing mice with AQ-modified hepatic proteins. This study used a soluble adjuvant known as ‘covax’ that has been reported to produce a better immune response than Freund’s adjuvant. After immunization, the mice were treated with 0.2% AQ in food for 5 weeks, as previously done. Paradoxically, the immunization protected animals from AQ-induced liver injury instead of exacerbating it. Consistent with this protection, immunization also appeared to lead to a tolerogenic response with an increase in myeloid derived suppressor cells, M2 macrophages, and FoxP3+T-cells. This attempt to develop an animal model of IDILI was unsuccessful and illustrated the complexity of the immune response and the difficulty of inducing a sustained immune response in the liver. It also reinforces the hypothesis that the key determinant of IDILI is immune tolerance. [ABSTRACT FROM PUBLISHER]

Delayed-type hypersensitivity (DTH) is a T-cell-mediated immune response that may be used for immunotoxicity testing in non-clinical species. However, in some cases DTH assays using T-dependent antigens may be confounded by the production of antibodies to the antigen. The authors have previously modified a DTH assay, initially validated in the mouse, for use in juvenile rats to assess the effect of immunosuppressive drugs on the developing rat immune system. The assay measures footpad swelling induced by subcutaneous footpad injection ofCandida albicans(C. albicans) derived-chitosan in rats previously sensitized withC. albicans. Antibodies to chitosan are not produced in this model. However, considerable inter-animal variability inherent in the footpad swelling assay can make it difficult to precisely quantify the magnitude of the immune response and inhibition by immunosuppressants, particularly if complete suppression is not observed. This report describes the development of anex vivoassay to assess DTH in rats using interferon (IFN)-γ production by splenocytes, obtained from rats sensitized withC. albicans, as the quantifiable measure of the DTH response. Adult and neonatal rats administered dexamethasone (DEX), a known immunosuppressant, exhibited immunosuppression as evidenced by a reduction inex vivoIFNγ production from splenocytes challenged withC. albicans-derived chitosan. Current data indicate that theex vivobased DTH assay is more sensitive than the conventional footpad swelling assay due to a lower background response and the ability to detect a response as early as post-natal day (PND) 12. Theex vivobased rat DTH assay offers a highly sensitive and quantitative alternative to the footpad swelling assay for the assessment of the immunotoxic potential of drugs. The increased sensitivity of theex vivoDTH assay may be useful for identifying smaller changes in response to immunotoxic drugs, as well as detecting responses earlier in animal development. [ABSTRACT FROM PUBLISHER]

Reconstitution of the immune function in chemotherapy patients will lead to decreases in post-operative complications. A preliminary investigation showed that an isoxazole derivative R-13 (3,5-dimethyl-isoxazole[5,4-e]8H-triazepin-4-one) hydrochloride, given in a single oral dose to normal mice, induced significant increases in the content of CD4+cells in the spleens and lymph nodes. That observation prompted the authors to assess the immune reconstituting effects of R-13 in mice pre-treated with cyclophosphamide (CP). Mice were given intraperitoneally (IP) a sublethal dose of CP (200 mg/kg) and then R-13 (as 20 µg IP doses, every 3 days post-CP treatment). Control mice, not treated with CP, received R-13 or the vehicle (DMSO in appropriate dilution). Blood leukocyte and splenocyte numbers, blood cell type levels, splenocyte spontaneous and ConA-induced proliferation, and delayed-type hypersensitivity (DTH) to ovalbumin (OVA) were investigated on day 15 post-CP treatment and five R-13 doses. The humoral immune response (antibody-forming cell development to sheep erythrocytes) was measured 30 days post-CP treatment and 10 R-13 doses. In CP-treated mice, five dosings with R-13 led to increases in numbers of splenocytes and blood leukocytes, as well as in spontaneous and ConA-induced splenocyte proliferation, relative to levels in mice that received only CP 15 days earlier. Blood analysis revealed decreases in neutrophil and eosinophil contents and an increased appearance of lymphocyte immature forms in all mice that received the R-13. Both cell-mediated responses to OVA and humoral immune response to sheep erythrocytes in CP-treated hosts were restored. Based on the data here, it is concluded that R-13 may be of potential value for reconstitution of the immune function of chemotherapy patients. [ABSTRACT FROM PUBLISHER]

Paraquat (PQ), one of the most widely used herbicides, has been used for several decades in agriculture. Some studies suggest that PQ has effects on the immune system. Moreover, previous studies have shown that PQ imparted some immunosuppressive effects. In the present study, cytotoxicity assays using splenic NK cells from mice treated for 28 days with PQ (at 0.2, 1, and 5 mg/kg) were performed to determine whether PQ altered the function of NK cells. Given that PQ was expected to induce an immunosuppressive effect, it was hypothesized that a gene involved in cellular metal ion homeostasis, metallothionein-1 (MT-1), could play an important role in this outcome. This belief was based on the fact thatMT1encodes a protein responsible for zinc ion homeostasis, and that a reduction in free zinc ion levels impairs NK cell function. The results showed that PQ treatments led to increased MT expression in several organs (liver, kidneys, testes) and in splenocytes, caused a reduction of both free zinc ions in sera and in free intracellular zinc, and reduced the expression of GATA-3, a zinc-finger transcription factor important for maturation and activity of T-cells and NK cells. These results provide a basis for a new molecular mechanism to describe potential immunosuppressive effects of PQin vivo. [ABSTRACT FROM PUBLISHER]

First responders (FR) present at Ground Zero in the first 72 h after the World Trade Center (WTC) collapsed have progressively exhibited significant respiratory injuries. The few toxicology studies performed to date evaluated effects from just fine (< 2.5 µm) WTC dusts; none examined health effects/toxicities from atmospheres bearing larger particle sizes, despite the fact the majority (> 96%) of dusts were > 10 µm and most FR likely entrained dusts by mouth breathing. Using a system that generated/delivered supercoarse (10-53 µm) WTC dusts to F344 rats (in a manner that mimicked FR exposures), this study sought to examine potential toxicities in the lungs. In this exploratory study, rats were exposed for 2 h to 100 mg WTC dust/m3 (while under isoflurane [ISO] anesthesia) or an air/ISO mixture; this dose conservatively modeled likely exposures by mouth-breathing FR facing ≈750-1000 mg WTC dust/m3. Lungs were harvested 2 h post-exposure and total RNA extracted for subsequent global gene expression analysis. Among the > 1000 genes affected by WTC dust (under ISO) or ISO alone, 166 were unique to the dust exposure. In many instances, genes maximally-induced by the WTC dust exposure (relative to in naïve rats) were unchanged/inhibited by ISO only; similarly, several genes maximally inhibited in WTC dust rats were largely induced/unchanged in rats that received ISO only. These outcomes reflect likely contrasting effects of ISO and the WTC dust on lung gene expression. Overall, the data show that lungs of rats exposed to WTC dust (under ISO) - after accounting for any impact from ISO alone - displayed increased expression of genes related to lung inflammation, oxidative stress, and cell cycle control, while several involved in anti-oxidant function were inhibited. These changes suggested acute inflammogenic effects and oxidative stress in the lungs of WTC dust-exposed rats. This study, thus, concludes that a single very high exposure to WTC dusts could potentially have adversely affected the respiratory system - in terms of early inflammatory and oxidative stress processes. As these changes were not compared with other types of dusts, the uniqueness of these WTC-mediated effects remains to be confirmed. It also still remains to be determined if these effects might have any relevance to chronic lung pathologies that became evident among FR who encountered the highest dust levels on September 11, 2001 and the 2 days thereafter. Ongoing studies using longer-range post-exposure analyses (up to 1-year or more) will help to determine if effects seen here on genes were acute, reversible, or persistent, and associated with corresponding histopathologic/biochemical changes in situ. [ABSTRACT FROM AUTHOR]

Recently, there has been a renewed interest in the use of the minipig as an alternative to dogs and non-human primates for conducting toxicological assessments in non-rodent species. Since the T-dependent antibody response (TDAR) is one of the most widely-accepted assays used in the assessment of immunocompetence, the present study was undertaken to characterize the primary and secondary TDAR to keyhole limpet hemocyanin (KLH) in the Göttingen Minipig®. Following primary immunization with either 2 or 10 mg KLH, anti-swine IgM and IgG ELISAs were optimized and individual animal responses were evaluated over time. Immunization with 10 mg KLH on Day 0 promoted primary IgM responses that peaked 6-9 days after antigen administration, while primary IgG levels peaked on Day 13 or 14. Secondary IgG antibody levels (following secondary injection with 2 mg KLH on Day 14) plateaued on Days 20-22. Anti-KLH antibody levels were decreased in minipigs treated with cyclophosphamide (CPS), a known immunosuppressant, at doses ranging from 12.5-50 mg/kg/day, while antibody levels in animals treated with 2.5 mg CPS/kg/day were similar to levels in saline-treated swine. These results demonstrate that the Göttingen Minipig® can be a useful alternative non-rodent species to the dog and the non-human primate for evaluating the TDAR to KLH in regulatory assessments of immunotoxicity. [ABSTRACT FROM AUTHOR]

Isoniazid (INH) is associated with one of the highest incidences of idiosyncratic drug-induced liver failure of any commonly prescribed drug. The mechanism of this liver injury remains uncertain, and a valid animal model would greatly facilitate mechanistic studies. Most studies of INH-induced liver toxicity have been acute studies performed in rats with high doses of the drug, and this is very different from the idiosyncratic liver injury that occurs in humans. It has previously been demonstrated that covalent binding of INH in the liver of mice is greater than in rats and more like that in humans. Therefore, mice should be a better species in which to develop an animal model of INH-induced liver injury. Treatment of Cbl-b−/− and PD1−/− mice, which have impaired immune tolerance, resulted in greater injury than their C57BL/6 background, but not liver failure. This suggested that the injury was mediated by the adaptive immune system; however, Rag−/− mice, which do not have competent T- and B-cells, sustained more liver injury than C57BL/6 wild-type mice. This suggested that the adaptive immune system also played a protective role. INH treatment also led to a decrease in the inflammatory cytokines IL-1α and IL-12, which suggests that the drug may have immunosuppressive properties. In short, a mouse model was developed of INH-induced liver injury in which the immune system appears to play a both protective and pathogenic role, but this study was unable to develop a model of INH-induced liver failure. [ABSTRACT FROM AUTHOR]

The classification of food allergens based on the structure and function of proteins contributes to the study of the relationship between bioinformatics and potential allergenicity of allergens. Food allergens always share sequence similarity with the allergens in the same allergen families. For that reason, food proteins from different allergen families may induce different patterns of immune responses in animal models. Female Balb/c mice (3-4-weeks-old) were sensitized with food proteins once per week for 4 weeks, and then challenged 2 weeks later (on Day 42 of study). Blood was collected (to obtain serum levels of histamine and protein-specific IgG1 and IgE antibodies) and measures of vascular permeability were performed 20 min after the challenge. Five food proteins (11S globulin, OVA [ovalbumin], HAS [human serum albumin] and LRP [lysine-responsive storage protein] of different allergen families, and Cry 1Ab/Ac [crystal protein]) were used to assess patterns of immune responses for each allergen family and then bioinformatics and digestive stability in simulated gastric fluid were employed to assess the overall utility of the Balb/c. The assay results indicated that, in this model, histamine and protein-specific IgE antibody levels and vascular permeability could be used to identify allergenicity of 11S globulin, OVA, and PAP (potato acid phosphatase) only. However, the results of the protein-specific IgG1 measures could only distinguish allergic food proteins with negative control. Based on bioinformatic analyses, the five different food proteins clearly induced distinct patterns of immune responses in the Balb/c model. [ABSTRACT FROM AUTHOR]

Aspergillus fumigatus is a filamentous fungus that produces abundant pigmented conidia. Several fungal components have been identified as virulence factors, including melanin; however, the impact of these factors in a repeated exposure model resembling natural environmental exposures remains unknown. This study examined the role of fungal melanin in the stimulation of pulmonary immune responses using immunocompetent BALB/c mice in a multiple exposure model. It compared conidia from wild-type A. fumigatus to two melanin mutants of the same strain, Δ arp2 (tan) or Δ alb1 (white). Mass spectrometry-based analysis of conidial extracts demonstrated that there was little difference in the protein fingerprint profiles between the three strains. Field emission scanning electron microscopy demonstrated that the immunologically inert Rodlet A layer remained intact in melanin-deficient conidia. Thus, the primary difference between the strains was the extent of melanization. Histopathology indicated that each A. fumigatus strain induced lung inflammation, regardless of the extent of melanization. In mice exposed to Δ alb1 conidia, an increase in airway eosinophils and a decrease in neutrophils and CD8+ IL-17+ (Tc17) cells were observed. Additionally, it was shown that melanin mutant conidia were more rapidly cleared from the lungs than wild-type conidia. These data suggest that the presence of fungal melanin may modulate the pulmonary immune response in a mouse model of repeated exposures to A. fumigatus conidia. [ABSTRACT FROM AUTHOR]

Increasingly in recent years, thyroid hormones (THs) have been considered to be important regulators of the immune system. However, their roles in host defense against viral infections are not clearly established. Therefore, this study was undertaken to examine proliferative activity and cytokine production by lymphocytes isolated from hyperthyroid and euthyroid Balb/c mice in response to herpes simplex virus-1 (HSV-1). Lymphocytes of hyperthyroid animals showed a significantly higher rate of proliferation and interferon (IFN)- γ production when compared with that by lymphocytes from euthyroid mice. In vitro thyroxine (T4) treatment was similarly effective in the potentiation of proliferation, but not IFN γ production, by euthyroid lymphocytes. Furthermore, the hyperthyroid state significantly attenuated ConA-, but not HSV-1-, induced interleukin (IL)-10 release; in vitro T4 treatment synergized this effect. These findings suggest that supra-physiologic TH levels (i.e. as occur in hyper-thyroid states) or in vitro TH treatment modulate T-helper (TH)1/TH2 lymphocyte responses and thereby amplifies host defenses against viral infections. One may also conclude that THs may have a potential application in viral immunization and/or treatment of viral infections. [ABSTRACT FROM AUTHOR]

Pediatric patients were recruited to analyze differences in Epstein-Barr virus (EBV) copy numbers and adaptive immune reactions in children with chronic active vs acute EBV infection (CAEBVI vs AEBVI), as well as to examine the relationship between these parameters and the pathogenesis of CAEBVI. Fluorescent qPCR was used to assess EBV-DNA levels, while ELISA, antibody affinity, flow cytometry, and heterophil agglutination (HA) assays were used to evaluate patient EBV-adaptive humoral and cellular immunity. Lastly, ELISPOT was employed to assess interferon (IFN)- γ secretory functions of EBV-specific cytotoxic T-lymphocytes (CTL) as a marker of subject EBV-specific adaptive cellular immunity. The results indicated that, compared with AEBVI patients or normal children, there was a dramatic elevation in viral copy levels, viral capsid antigen (VCA)-IgA, early antigen (EA)-IgA, and EA-IgG, but a lack of EBV nuclear antigen (EBNA)-IgG and a negative HA in CAEBVI patients ( p < 0.01). These subjects also had decreased CD4+, CD8+ (naïve), CD8+CD38+, and effective memory T-lymphocyte levels compared with AEBVI patients ( p < 0.01), and decreased EBV-specific CTL function compared with normal children ( p < 0.01). These results suggest that there is a disturbance in EBV antigen availability and in both the adaptive humoral and cellular immune responses in patients with CAEBVI, and that these outcomes may be associated with the chronic active re-infection process itself associated with CAEBVI. [ABSTRACT FROM AUTHOR]

It is well established that certain chemicals cause respiratory allergy. In common with contact allergens, chemicals that induce sensitization of the respiratory tract must form stable associations with host proteins to elicit an immune response. Measurement of the reactivity of chemical allergens to single nucleophilic peptides is increasingly well-described, and standardized assays have been developed for use in hazard assessment. This study employed standard and modified peptide reactivity assays to investigate the selectivity of chemical respiratory allergens for individual amino acids under competitive and non-competitive conditions. The reactivity of 20 known chemical respiratory sensitizers (including diisocyanates, anhydrides, and reactive dyes) were evaluated for reactivity towards individual peptides containing cysteine, lysine, histidine, arginine, or tyrosine. Respiratory allergens exhibited the common ability to deplete both lysine and cysteine peptides; however, reactivity for histidine, arginine, and tyrosine varied between chemicals, indicating differences in relative binding affinity toward each nucleophile. To evaluate amino acid selectivity for cysteine and lysine under competitive conditions a modified assay was used in which reaction mixtures contained different relative concentrations of the target peptides. Under these reaction conditions, the binding preferences of reference respiratory and contact allergens (dinitrochlorobenzene, dinitrofluorobenzene) were evaluated. Discrete patterns of reactivity were observed showing various levels of competitive selectivity between the two allergen classes. [ABSTRACT FROM AUTHOR]

In recent decades, in the US and in Western and Northern Europe, there has been a significant increase in the prevalence of atopic allergic disease. Although that increase may now be slowing, or have already reached a plateau, there remains considerable interest in the factor or factors that may have caused this increased susceptibility to allergy and asthma. Certainly, the changes recorded have been too rapid to implicate a change in the gene pool, and for that reason attention has focused on the possible impact of environmental, dietary, and lifestyle factors. Although the hygiene hypothesis proposes that increased susceptibility to allergic sensitization is associated with changes in childhood exposure pathogenic microorganisms, other factors have been considered also. Among these is exposure to chemicals and atmospheric pollutants. There is some evidence that exposure to certain chemicals may elicit or exacerbate respiratory reactions in those who are already sensitized, or who already have existing airway disease. However, a recent article has proposed that exposure to specific household cleaning products may be one factor that is able to affect susceptibility to allergic sensitization. In the light of that article it is timely now to consider again the ability of chemical exposure to influence sensitization to common antigens. [ABSTRACT FROM AUTHOR]

There is currently no validated animal model for evaluating the potential allergenicity of food proteins. This study aimed to compare the allergic reactions between BN and Wistar rats after oral exposure to ovalbumin (OVA) by studying immune responses and clinical manifestations. Female BN and Wistar rats were orally exposed to OVA on days 1 and 14, and thereafter daily from day 15 to day 42. Sera and plasma were screened for OVA-specific antibodies and histamine. On day 49, all the OVA-sensitized animals were orally challenged with OVA before blood pressure was measured. One day later (on day 50), histopathology and differential cell counts were performed. The results indicate that oral exposure of BN rats to OVA yielded IgE, IgG, and IgG2a antibody responses that were generally of higher levels than those observed in Wistar rats ( p < 0.05). However, the Wistar rats presented with more serious clinical manifestations and histopathologic changes that could have serious implications for any OVA-induced anaphylaxis. The studies here proved that OVA-sensitized BN and Wistar rats evinced different immune responses and clinical manifestations; these outcomes suggested that the two rat strains might differ in their immunologic mechanisms of allergy and that there was no correlation between immune responses and the severity of clinical symptoms. To be clear, the data from these studies should be viewed as 'preliminary', as only a single protein allergen was examined. Accordingly, further studies are needed to compare the allergic reactions between BN and Wistar rats by using purified strong-, weak-, and non-allergenic proteins based on the experiments reported here. [ABSTRACT FROM AUTHOR]

Histamine, involved in many inflammatory reactions and immune responses, is reported to suppress-via H4R stimulation-injury concomitant with the late phase of warm hepatic ischemia/re-perfusion (I/R). The current study investigated the possible effects of histamine on the acute phase of hepatic I/R injury, and the possible underlying mechanisms like oxidative stress and release of inflammatory cytokines (e.g., tumor necrosis factor (TNF)-α nd interleukin [IL]-12). Rats were divided into naïve, sham-operated, and I/R groups. The I/R group was divided into sub-groups and pre-treated with histaminergic ligands before induction of ischemia. Anesthetized rats were subjected to warm ischemia for 30 min by occlusion of the portal vein and hepatic artery, then re-perfused for 90 min. Rats in the control I/R group showed significant increases in hepatic malondialdehyde (MDA), TNF α, and IL-12 contents, and in plasma alanine transaminase (ALT) and aspartate transaminase (AST) levels, along with significant decreases in hepatic reduced glutathione (GSH) content and marked diffuse histopathologic damage. Pre-treatment with histamine resulted in significant mitigation of each of these end-points. The protective effect of histamine was not antagonized by pre-treatment with mepyramine (H1R antagonist) or ranitidine (H2R antagonist) and completely reversed by pre-treatment with thioperamide (H3R and H4R antagonist). In addition, the histamine protective effect was mimicked by pre-treatment of rats with clozapine (H4R agonist). These observations strongly suggested that histamine has a protective effect against hepatic I/R-mediated tissue injury during the acute phase, and this effect was mediated through an H4R stimulation that led to a decrease in IL-12 and TNF α production-outcomes that consequently decreased localized oxidative stress and afforded hepatic protection in general. [ABSTRACT FROM AUTHOR]

It has been shown that naturally occurring regulatory T-cells (CD4+CD25+ Foxp3+ T-cells) have critical roles in tumor invasion and down-regulation of immune response against established tumors. High expression of CD25 (IL-2R α) by regulatory T (Treg) cells may cause an inefficient response when using IL-2-based cancer vaccines. It seems that selective elimination of Treg cells before treatment of tumor-bearing T-cells can strongly increase the efficacy of a vaccine. The aim of this study was to set up an efficient cost-effective protocol to eliminate CD4+CD25+ T-cells-using the immunotoxin anti-tac-SAP. Peripheral blood mononuclear cells (PBMC) taken from colon cancer patients were treated with different concentrations (i.e., 0-100 µg/dl) of the immunotoxin. Flow cytometric analyses were then preformed to analyze expression of CD4, CD25, CD3, CD8, and CD45 surface markers; semi-quantitative fluorescent-PCR was used for the detection of Foxp3 expression before and after anti-tac-SAP treatment. The results indicated that anti-tac-SAP effectively eliminated CD4+CD25+ Treg cells and that 25 µg/dl was the optimal concentration of anti-tac-SAP for selective depletion of these cells. These outcomes were verified by analyses of Foxp3 expression. The results also indicated that this immunotoxin had no non-specific effects on other T-cells, including CD4+CD25− and CD8+CD45+ T-cells. Building on the work here, ongoing/future studies with the anti-tac-SAP will focus on functional assessments of the remaining (i.e., non-eliminated) T-cells (i.e., CD8, CD4; using proliferation and peptide sensitization assays) to ascertain if the immunotoxin inadvertently alters the functions of these cells-an untoward outcome. [ABSTRACT FROM AUTHOR]

Chromium and nickel cause allergic contact dermatitis, a common biological skin response to sensitizing agents. This study used a conventional in vitro wounding model to study the impact of sensitizing agents on the innate immune response of human keratinocytes. Experiments were designed to evaluate the involvement of specific Toll-like receptors and metalloproteinases as effectors molecules downstream, at a molecular level. Further, keratinocytes were co-cultured with monocytes (THP-1 cells) to reproduce an inductive stimulus on monocytes made by metals. Human keratinocytes (HaCat) were grown on plates covered with collagen type I, chemically treated, and then mechanically injured with a sterile pipette tip. Restoration of the monolayer integrity was monitored by time-lapse video microscopy. Effector gene expression was evaluated by real-time PCR. The presence of chromium significantly dropped the rate of wound closure, while nickel-induced hyper-proliferation ended in an acceleration of the healing process, an event that does not occur in vivo. This latter outcome led to considering nickel as an unsuitable example for use in the experimental model. Focusing solely on the chromium aspect of this study, RNA profiles of selected molecular markers were generated to ascertain if the detrimental stimulus from chromium was eliminated or persisted both in keratinocytes alone and/or during co-cultures of keratinocytes and monocytes. Monocytes accelerated the process of wound repair. This in vitro experimental model highlighted the involvement of innate immunity in response to chromium and might be useful for test molecules of therapeutic interest for the treatment of skin lesions. However, the experience with nickel reveals that there are limitations to the utility of this wound model system after all. [ABSTRACT FROM AUTHOR]

Vaccines represent a potent tool to prevent or contain diseases with high morbidity or mortality. However, despite their widespread use, there is still a limited understanding of the mechanisms underlying the effective elicitation of protective immune responses by vaccines. The integrated co-operation between cells and molecules of innate and adaptive immune systems is under intense study by several groups and constantly updated. The recent development of new technologies and computational tools permits the comprehensive and quantitative analysis of the interactions between all of the components of immunity over time. This study reviews recent progress in exploiting an immunogenomics approach, within the systems biology strategy, to study and evaluate vaccine strategies for infectious and neoplastic diseases. The final goal of this approach is 2-fold, looking for novel and unpredictable mechanisms as well as identifying common immune signatures, relevant for predicting immune responsiveness to improve the design of vaccine strategies. Such approach, indeed, would enable the switch from 'empirical' to 'knowledge-based' vaccinology, leading to a patient-tailored treatment. [ABSTRACT FROM AUTHOR]

Immunotherapy in the treatment of cancer is increasing, particularly with the recent FDA approval of sipuleucel-T and ipilimumab. The efficacy of anti-tumor immunotherapies has been modest compared to their theoretical and pre-clinical promise. This review evaluates the promise and pitfalls of immunotherapy and highlight some of the obstacles to improving anti-tumor immunotherapy: the need for technical refinement of therapies, the need for an increased understanding of how best to combine therapies with traditional cytotoxic therapies, the inability of patients to mount an effective immune response either due to disease burden or tumor induced immune suppression, the significant toxicities associated with many immunotherapies, and the lack of strongly immunogenic antigens required by many therapies. Further, antigen-non-specific immunotherapies, including cytokines such as interleukins and interferons, immuno-stimulatory agents such as CpG oligonucleotides, or BCG, antibodies targeted against receptors such as the agonistic CD40 or inhibitory CTLA-4 antibodies, and enzyme inhibitors such as those targeting cyclo-oxygenase or indolamine-2,3-dioxygenase are discussed. In addition, potential mechanisms of these therapies such as direct anti-tumor effects, reversal of immune suppression, activation of innate immunity, and antigen-non-specific T-cell activation are reviewed. We also appraise the potential of these antigen-non-specific therapies to overcome some of the previously described pitfalls of immunotherapy. Lastly, we discuss a recent series of studies from our laboratory demonstrating the importance of antigen-non-specific 'bystander activation' of memory T-lymphocytes by immunomodulatory therapies such as interleukin-2 and the antigen-non-specific anti-tumor effects of these cells. [ABSTRACT FROM AUTHOR]

Dendritic cells are characterized by the ability to induce primary antigen-specific immune responses in both major histocompatibility complex (MHC) Class I-restricted CD8 cells and MHC Class II-restricted CD4 cells. This professional antigen presentation function is associated with the up-regulation of co-stimulatory molecules and Class II MHC. While it has been recognized that several types of innate lymphocytes in mouse and humans can express co-stimulatory molecules and present antigen, the property of antigen presentation to elicit responses in naïve cells has been considered the exclusive domain of the dendritic cell. This concept has been challenged through the description of innate lymphocytes, capable of killing using NK receptors, but also up-regulating co-stimulatory molecules and driving the antigen-specific proliferation of naïve lymphocytes to the same extent as dendritic cells. Interferon (IFN)- γ secreting killer dendritic cells (IKDC) have been described in mice and share immunophenotypic properties of both dendritic cells and natural killer cells. Human blood γδ T-lymphocytes have innate tumor cell killing properties by both antibody-dependent and natural killer receptor-dependent mechanisms. This article reviews data from the authors' own laboratory showing a particular feature in common between the mouse IKDC and human blood γδ T-lymphocytes; namely their requirement for interaction with a target cell for specific licensing for professional antigen presentation. [ABSTRACT FROM AUTHOR]

Welding fume inhalation affects the immune system of exposed workers. Manganese (Mn) in welding fume may induce immunosuppressive effects. The goal was to determine if Mn in welding fume alters immunity by reducing the number of circulating total leukocytes and specific leukocyte sub-populations. Sprague-Dawley rats were treated by intratracheal instillation (ITI) with either a single dose (2.00 mg/rat) or repeated doses (0.125 or 2.00 mg/rat for 7 weeks) with welding fumes that contained different levels of Mn. Additional rats were treated by ITI once a week for 7 weeks with the two doses of manganese chloride (MnCl2). Bronchoalveolar lavage was performed to assess lung inflammation. Also, whole blood was recovered, and the number of circulating total leukocytes, as well as specific lymphocyte subsets, was determined by flow cytometry. The welding fume highest in Mn content significantly increased lung inflammation, injury, and production of inflammatory cytokines and chemokines compared to all other treatment groups. In addition, the same group expressed significant decreases in the number of circulating CD4+ and CD8+ T-lymphocytes after a single exposure, and significant reductions in the number of circulating total lymphocytes, primarily CD4+ and CD8+ T-lymphocytes, after repeated exposures (compared to control values). Repeated MnCl2 exposure led to a trend of a reduction (but not statistically significant) in circulating total lymphocytes, attributable to the changes in the CD4+ T-lymphocyte population levels. The welding fume with the lower concentration of Mn had no significant effect on the numbers of blood lymphocytes and lymphocyte subsets compared to control values. Evidence from this study indicates that pulmonary exposure to certain welding fumes cause decrements in systemic immune cell populations, specifically circulating T-lymphocytes, and these alterations in immune cell number are not dependent exclusively on Mn, but likely a combination of other metals present in welding fume. [ABSTRACT FROM AUTHOR]

The present study was performed to assess the immune response in women with human papilloma virus (HPV) DNA+ and DNA− cervical lesions. Eighty women with cervical lesions (age range = 25-70 years) and 20 healthy individuals (control group) were enrolled in the study. Lesions were cytologically classified into four groups: ASC-US (20), CINI (30), CINII-III (16), and cervical carcinoma (14) prior to HPV DNA detection. Estimation of interleukin (IL)-10 and tumor necrosis factor (TNF)- α levels in cervical secretions and serum of the studied patients was performed utilizing ELISA. PCR screening kits were used to detect HPV DNA in cervical smears obtained from the studied cases with the different lesions. IL-10 levels in cervical secretions of HPV DNA+ were significantly greater than those from DNA− patients (i.e., 88.73 vs 24.00 pg/ml) and from controls (i.e., 88.73 vs 8.27 pg/ml) and the levels were higher in DNA− patients than in controls (i.e., 24.00 vs 8.27 pg/ml). In comparison, serum IL-10 levels in these patients did not significantly differ from control values (i.e., 13.69 vs 12.16 vs 9.99 pg/ml, respectively). TNF α levels in cervical secretions of the HPV DNA+ and DNA− cases did not significantly differ from values for the controls (i.e., 12.18 vs 9.90 vs 7.90 pg/ml, respectively). Serum TNF α of these patients also did not differ significantly from controls (i.e., 11.59 vs 11.90 vs 10.83 pg/ml, respectively). The detected levels of IL-10 in cervical secretions of patients with HPV DNA+ lesions was significantly higher than in their sera, while secretion TNF α levels were nominally greater than sera values. Lastly, higher levels of IL-10 were observed in secretions of 10-14 (71.4%) patients who had progressive cervical lesions (HSIL and cervical cancer stages) who were HPV DNA+ than observed in 20 of 66 (30.0%) of DNA− patients with similar progressive lesions. In general, the higher levels of IL-10 than of TNF α suggested a potential down-modulation of tumor-specific immune responses to HPV-infected lesions. This phenomenon appears to provide a tumor 'progressive' microenvironment in these particular patients. [ABSTRACT FROM AUTHOR]

This study was designed to evaluate some immunological responses of male White Leghorn (WL) chicks kept on an ochratoxin A (OTA)-contaminated diet. For this purpose, 350 1-day-old male WL chicks were divided into five groups (A-E). Group A was kept as control, while Groups B, C, D, and E were fed OTA-contaminated feed at 0.1, 0.5, 1.0, and 1.5 mg/Kg diet, respectively, for 21 days, and then basal ration for the remaining period. At 14- and 16-days of age, random chicks ( n == 10) from each group were used for analyses of phagocytic function of the reticuloendothelial system or for measuring the lymphoproliferative responses to intradermally-administered T-cell mitogen, phytohemagglutinin-P (PHA-P), respectively. At 30-days of age, abdominal macrophages were collected from 15 chicks/group and utilized for determination of their phagocytic potential and for nitrite production. Antibody (Ab) titers (i.e., total antibodies, IgM, and IgG) against sheep red blood cells (SRBC) were determined at 7 and 14 days after a primary (at 7 days of age) and a booster (given 14 days after primary [at 21-days of age]) dose (intravenous) of the antigen. Data from the present study showed that the relative weight of the bursa of Fabricius of chicks fed OTA for 14 and 21 days and the spleen of chicks fed OTA for 21 days were significantly lower than their control counterpart. Phagocytic function of reticuloendothelial system evaluated by carbon clearance, and lymphoproliferative response to PHA-P, of chicks kept on OTA-contaminated diet were significantly lowered. The percentage of abdominal macrophages displaying phagocytosis of SRBC, the number of SRBC/macrophage, and nitrite production were each significantly lower in cells from chicks in the OTA-fed groups. Total Ab (at days 7 and 14 post-booster SRBC injection) and IgG (at day 14 post-primary and day 7 post-booster SRBC injection) titers against SRBC showed significant reductions in the groups fed OTA-contaminated diet. The findings of this study are in line with the previous work suggesting the immunosuppressive effect of OTA in male WL chicks regarding functional impairment in some of the components of the immune system. [ABSTRACT FROM AUTHOR]

Cell-mediated immunity offers protection against virus-infected cells and tumor cells, involves activation of natural killer (NK) cells, production of antigen-specific cytotoxic T-lymphocytes, and release of various cytokines in response to an antigen. Administration of an ethanolic extract of Aerva lanata was found to stimulate cell-mediated immunological responses in normal and tumor-bearing BALB/c mice. A significant enhancement in NK cell activity in both normal and tumor-bearing hosts was observed after administration of A. lanata. Antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent complement-mediated cytotoxicity (ACC) were significantly enhanced as well in both sets of treated hosts. In addition, in vivo production of IL-2 and IFNg were each significantly enhanced by extract treatment. The stimulatory effect of A. lanata on cytotoxic T-lymphocyte (CTL) production was determined by Winn's neutralization assay using CTL-sensitive EL4 thymoma cells. A. lanata treatment caused a significant increase in CTL production in both in vivo and in vitro models, in each case as indicated by a significant increase in the life-spans of tumor-injected mice. Taken together, all of these results in the murine model indicate that administration of an ethanolic extract of A. lanata could enhance the cell-mediated anti-tumor response. [ABSTRACT FROM AUTHOR]

Plants may have the ability to modulate immune responses. In the present study, the effects of three plants belonging to Labiatae family, each traditionally used for the treatments of infections and inflammatory diseases, as well as the role of thymol (as one the major components of these plants), were investigated for their potential to affect the activation of lymphocytes. Four organic extracts of Thymus vulgaris and two other plants (i.e., T. daenensis and Zataria multiflora) were prepared. The effect of the extracts on mitogen (PHA)-stimulated peripheral blood lymphocytes was determined using a cell proliferation assay. The hexane extracts obtained from the three plants showed the strongest inhibitory effects on PHA-induced proliferation. Use of preparative thin layer and gas chromatographies in conjunction with the proliferation assay confirmed that thymol was the major component responsible for the observed effects from the three plants. Thymol inhibited inducible lymphocyte proliferation in a concentrationdependent manner, with reductions ranging from 62.8% at 50 µg/ml to 89.8% at 200 µg/ml (> 0.1 µg/ml (p < 0.01). Flow cytometric analysis using propidium iodide staining showed that the inhibitory effect of thymol at 200 µg/ml was due to a cytotoxic activity. In conclusion, the three Labiatae plants studied here each showed immunosuppressive effects against lymphocytes and it was most likely that thymol was the compound in these plants responsible for this effect. [ABSTRACT FROM AUTHOR]

In addition to the effector T-cells subsets, T-cells can also differentiate into cells that play a suppressive or regulatory role in adaptive immune responses. The cell types currently identified as regulatory T-cells (Tregs) include natural or thymic-derived Tregs, T-cells which express Foxp3+CD25+CD4+ and can suppress immune responses to autoreactive T-cells, as well as inducible Tregs, that are generated from naïve T-cells in the periphery after interaction with antigens presented by dendritic cells. Inducible Tregs include TH3 cells, Tr1 cells, and Foxp3+-inducible Tregs. Tregs have been shown to be critical in the maintenance of immune responses and T-cell homeostasis. These cells play an important role in suppressing responses to self-antigens and in controlling inappropriate responses to non-self-antigens, such as commensal bacteria or food in the gut. For example, depletion of CD4+CD25+ Tregs from mice resulted in the development of multi-organ autoimmune diseases. CD4+CD25+ Tregs and/or IL-10-producing Tr1 cells are capable of suppressing or attenuating TH2 responses to allergens. Moreover, adoptive transfer of CD4+CD25+ Tregs from healthy to diseased animals resulted in the prevention or cure of certain autoimmune diseases, and was able to induce transplantation tolerance. Clinical improvement seen after allergen immunotherapy for allergic diseases such as rhinitis and asthma is associated with the induction of IL-10- and TGFβ-producing Tr1 cells as well as FoxP3- expressing IL-10 T-cells, with resulting suppression of the TH2 cytokine milieu. Activation, expansion, or suppression of CD4+CD25+ Tregs in vivo by xenobiotics, including drugs, may therefore represent a relevant mechanism underlying immunotoxicity, including immunosuppression, allergic asthma, and autoimmune diseases. [ABSTRACT FROM AUTHOR]

Nanomaterial of titanium dioxide (TiO2) is manufactured in large-scale production plants, resulting in risks for accidental high exposures of humans. Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects. By using the Dark Agouti (DA) rat, a strain disposed to develop chronic inflammation following exposure to immunoactivating adjuvants, we investigated local and systemic inflammatory responses after lung exposure of nanosized TiO2 particles up to 90 days after intratracheal instillation. TiO2 induced a transient response of proinflammatory and T-cell-activating cytokines (interleukin [IL]-1αα, IL-1ββ, IL-6, cytokine-induced neutrophil chemoattractant [CINC]-1, granulocyte--macrophage colony-stimulating factor [GM-CSF], and IL-2) in airways 1--2 days after exposure, accompanied by an influx of eosinophils and neutrophils. Neutrophil numbers remained elevated for 30 days, whereas the eosinophils declined to baseline levels at Day 8, simultaneously with an increase of dendritic cells and natural killer (NK) cells. The innate immune activation was followed by a lymphocyte expansion that persisted throughout the 90-day study. Lymphocytes recruited to the lungs were predominantly CD4++ helper T-cells, but we also demonstrated presence of CD8++ T-cells, B-cells, and CD25++ T-cells. In serum, we detected both an early cytokine expression at Days 1--2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γγ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-αα), indicating systemic late-phase effects in addition to the local response in airways. In summary, these data demonstrate a dynamic response to TiO2 nanoparticles in the lungs of DA rats, beginning with an innate immune activation of eosinophils, neutrophils, dendritic cells, and NK cells, followed by a long-lasting activation of lymphocytes involved in adaptive immunity. The results have implications for the assessment of risks for adverse and persistent immune stimulation following nanoparticle exposures in sensitive populations. [ABSTRACT FROM AUTHOR]

The immune system is a critical element involved in the control of tumor development and progression. While we have learned how to manipulate the immune system to generate tumor-specific immune responses, cancer immunotherapy has not yet delivered substantial clinical benefits. It has become increasingly clear that tumor-induced abnormalities in the immune system not only hamper natural tumor immune surveillance, but also limit the effect of cancer immunotherapy. If the results of recent studies are of any indication, then we are on the verge of a real breakthrough in our understanding of the immunobiology of tumor-host interactions and of ways to manipulate it. This 1st International Conference on “Cancer Immunotherapy and Immunomonitoring (CITIM)” was the first meeting in Eastern Europe to specifically focus on the issue of immune regulation in the tumor environment, cancer immunotherapy, and immunomonitoring of immunotherapeutic clinical trials. This CITIM Conference held in Kiev, Ukraine, was comprised from eight plenary sessions and two special selected poster presentation sessions. Selected contributions from the participants of the Conference are presented in this issue of the Journal of Immunotoxicology. [ABSTRACT FROM AUTHOR]