In vitro effect of 4-pentylphenol and 3-methyl-4-nitrophenol on murine splenic lymphocyte populations and cytokine/granzyme production

Gasoline exhaust particles (GEP) and diesel exhaust particles (DEP) are considered to be some of the most important air pollutants. Among the many constituents in these pollutant particles, 4-pentylphenol (PP) and 3-methyl-4-nitrophenol (PNMC) are considered important phenolics in GEP and DEP, respectively. The aim of this study was to investigate the effect of in vitro exposure to commercially-supplied PP and PNMC on populations of, and production of interleukin (IL)-2, IL-4 and granzyme-B by, mouse splenic lymphocytes. After in vitro exposure to PP or PNMC for 48 h, splenocyte viability was measured, cell phenotypes, e.g. B-cell (CD19), T-cells (CD3), T-cell subsets (CD4 and CD8), were quantified by flow cytometry and production of IL-2, IL-4 and granzyme-B was assessed via ELISA. The oxidative toxicity of PP and PNMC toward the splenocytes was also evaluated using measures of hydroxyl radical and malondiadehyde production and changes in glutathione peroxidase and superoxide dismutase activities. Results showed that in vitro exposure to PP and PNMC inhibited splenic cell parameters in a dose-related manner. Exposure to PP and PNMC decreased splenic T-lymphocyte populations and splenocyte production of cytokines and granzyme B, as well as induced oxidative stress in the splenocytes. The results also showed that the percentages of CD3⁺ T-cells overall and of CD4⁺ and CD8⁺ T-cells therein, among exposed splenocytes, were reduced; neither compound appeared to affect levels of CD19⁺ B-cells. Overall, the suppressive effects of PP were stronger than PNMC. The data here provide support for the proposal that PP-/PNMC-induced toxicity in splenocytes may be due at least in part to oxidative damage and that PP and PNMC – as components of GEP and DEP – might significantly impact on splenic T-cell formation/release of cytokines/granzymes in situ.     

Modulation of macrophage functionality induced in vitro by chlorpyrifos and carbendazim pesticides

The immune response is the first defense against pathogens; however, it is very sensitive and can be impacted on by agrochemicals such as carbamate and organophosphate pesticides widely present in the environment. To understand how pesticides can affect immune cell function in vitro, this study investigated the effects of chlorpyrifos (CPF) and carbendazim (CBZ), the most commonly used pesticides worldwide, on murine immune cell (i.e. macrophage) functions, including lysosomal enzyme activity and pro-inflammatory cytokines (IL-1β and TNFα) and nitric oxide (NO) production by isolated mouse peritoneal macrophages. This study showed for the first time that CPF and CBZ dose-relatedly reduced macrophage lysosomal enzyme activity and LPS-induced production of IL-1β, TNFα and NO. In general, the effects caused by CPF appeared more pronounced than those by CBZ. Collectively, these results demonstrated that CPF and CBZ exhibited marked immunomodulatory effects and could act as potent immunosuppressive factors in vitro. This inhibition of macrophage pro-inflammatory function may be an integral part of the underlying mode of action related to pesticide-induced immunosuppression.     

Long‐term exposure to high levels of decabrominated diphenyl ether inhibits CD4 T‐cell functions in C57Bl/6 mice

In recent years, the adverse health effects of decabrominated diphenyl ether (BDE‐209) have raised more concerns as a growing number of studies reported its persistence in the environment and abundance in the human population, especially in occupational environmental compartments and exposed personnel. This study applies our previous animal model simulating occupational exposure to BDE‐209 to investigate its potential adverse effects on CD4 T cells. Female C57Bl/6 mice were orally gavaged with BDE‐209 at a dose of 800 mg kg^?1 every 2 days for 10 months and the blood of each mouse was collected for analysis. Kinetic changes of the peripheral immune system were investigated from 1 to 5 months of exposure. The chronic effects on cytokine production, proliferation and the antigen‐specific responses of CD4 T cells were evaluated at 7, 9 and 10 months, respectively. The results have shown that impaired proliferation and cytokine (IFN‐γ, IL‐2 or TNF‐α) production of CD4 T cells were observed in BDE‐209‐exposed mice, accompanied by increased T regulatory cells in the blood. BDE‐209 exposure in vitro also suppressed the reactivity of CD4 T cells at concentrations of 0.01, 0.1, 1 and 10 μM. Furthermore, we observed weaker antigen‐specific CD4 T‐cell responses to Listeria monocytogenes infection in the mice exposed to BDE‐209, suggesting decreased resistance to exogenous pathogens. Taken together, these observations indicate an impaired cellular immunity after long‐term and relative high‐dose exposure to BDE‐209 in adult mice. Copyright © 2015 John Wiley & Sons, Ltd.     

水环境镉对鲫鱼免疫毒性的研究

目的：探讨环境重金属镉对鲫鱼免疫功能的影响。方法：将鲫鱼分置于含不同浓度CdCl2的水中饲养,10天后取鱼称重,采血进行白细胞计数,分离血清检测溶菌酶含量,解剖前肾,检测巨噬细胞吞呀鸡红细胞的吞噬率和吞噬指数。结果：表明低镉组（2．5ug/L)鱼血白细胞数显高于对照组,而中,高镉组（5．0ug/L,10.0ug/L)与对照组相比却无显差异。血清溶菌酶含量随镉浓度的增高有升高的趋势,且高镉组明显高于对照组,此外,各染镉组鱼前肾巨噬细胞的吞噬率,吞噬指数与对照组相比均无判别。结论：提示镉对鲫鱼的免疫功能有一定的影响,对鲫鱼免疫功能的测定可作为水生环境污染的生物检测手段。     

外源性镉金属硫蛋白对小鼠脾淋巴细胞功能影响的研究

目的 分析外源性镉金属硫蛋白（CdMT）的免疫毒性。方法 采用分离纯化经诱导合成的CdMT作为受试物与CdCI2比较,经口给予BALB／C小鼠不同剂量染毒2周和4周,检测脾T淋巴细胞增殖和T细胞亚群评价细胞免疫功能。结果 与阴性对照和脱金属硫蛋白（Apo-MT)组相比,CdMT组和CdCI2组表现为T细胞增殖功能降低;L3T4^ 亚群减少、Lyt2^ 亚群升高、L3T4^ /Lyt2^ 比值降低;且在CdMT组的改变明显低于相同含量的CdCI2组。结论 外源性CdMT经口作用可体内脾淋巴细胞免疫抑制作用,并与染毒剂量和时间有关,但CdMT经口免疫毒性低于CdCI2;结果可为评价环境镉暴露的生物学作用提供依据。     

CRF阻断镉对大鼠脾淋巴细胞免疫毒性的体外实验研究

目的：探讨体外镉的免疫功能抑制过程中促肾上腺皮质激素释放因子（CRF）的修饰调节作用。方法：离体培养大鼠脾淋巴细胞,用^3H-TdR掺入法测定分别在给氯化镉、CRF及两者联合作用条件下的T、B淋巴细胞的增殖转化功能。结果：镉抑制大鼠脾淋巴细胞的增殖转化,各染镉实验组T、B淋巴细胞增殖指数低于对照组（P＜0．05）;且有随剂量升高而而降低的趋势;1．0－100．0nmol/L CRF标准浓度组T、B淋巴细胞增殖指数明显高于对照组（P＜0．05）;当以1．0nmol/L CRF与5－20 μmol/L氯化镉联合作用时两种免疫细胞的增殖功能依然明显受到刺激,各实验组^3H-TdR掺入率高于对照组（P＜0．05）。结论：体外CRF能增强免疫细胞增殖活性并可阻断镉对T、B淋巴细胞的增殖抑制毒性。     

胸腺在免疫毒性病理学评价中的作用和意义

胸腺是中枢性淋巴器官，无须抗原的刺激T淋巴细胞在皮质自主地进行分化和成熟，这是免疫系统正常功能发育的重要组成部分。当暴露于免疫毒性物质和内源性糖皮质激素时，胸腺是敏感的靶器官，胸腺的大小或重量出现明显的降低，这往往是化合物或药物导致的敏感的皮质胸腺细胞改变最初观测到的指标。因此，胸腺组织病理学和重量的改变与免疫毒性的筛选具有特定的关联，对胸腺的病理学评价在免疫毒性研究中具有重要作用和意义。文中从胸腺生理和毒性病理学的角度对其作用和研究意义进行综述。     

Investigations of immunotoxicity and allergic potential induced by topical application of triclosan in mice

Triclosan is an antimicrobial chemical commonly used occupationally and by the general public. Using select immune function assays, the purpose of these studies was to evaluate the immunotoxicity of triclosan following dermal exposure using a murine model. Triclosan was not identified to be a sensitizer in the murine local lymph node assay (LLNA) when tested at concentrations ranging from 0.75–3.0%. Following a 28-day exposure, triclosan produced a significant increase in liver weight at concentrations of ≥ 1.5%. Exposure to the high dose (3.0%) also produced a significant increase in spleen weights and number of platelets. The absolute number of B-cells, T-cells, dendritic cells and NK cells were significantly increased in the skin draining lymph node, but not the spleen. An increase in the frequency of dendritic cells was also observed in the lymph node following exposure to 3.0% triclosan. The IgM antibody response to sheep red blood cells (SRBC) was significantly increased at 0.75% – but not at the higher concentrations – in the spleen and serum. These results demonstrate that dermal exposure to triclosan induces stimulation of the immune system in a murine model and raise concerns about potential human exposure.     

Systemic immunosuppression following a single pharyngeal aspiration of 1,2:5,6-dibenzanthracene in female B6C3F1 mice

1,2:5,6-Dibenzanthracene (DBA) is ubiquitous in our environment as a contaminant produced by incomplete combustion of organics from sources such as forest fires, cigarette smoke, and asphalt paving, and it is more immunosuppressive of the T-dependent antibody-forming cell (AFC) response than the well-studied polycyclic aromatic hydrocarbon, benzo(a)pyrene. The systemic immunosuppressive effects of DBA were investigated following a single pharyngeal aspiration (pa) in female B₆C₃F₁ mice. The immunotoxic effects of DBA were evaluated using numerous assays of varying complexity to evaluate innate (natural killer [NK] cell activity), cell-mediated (T-lymphocyte proliferation, mixed leukocyte response [MLR], cytotoxic T-lymphocyte [CTL] activity, delayed-type hypersensitivity [DTH]), and humoral immunity (B-lymphocyte proliferation, T-dependent antibody responses). A single pa of DBA at doses up to 30?mg/kg had no effect on NK cell activity, anti-CD3 antibody-mediated T-lymphocyte proliferation, the MLR, or B-lymphocyte proliferation. DBA at 30?mg/kg suppressed Concanavalin A (ConA)-stimulated T-lymphocyte proliferation and the CTL response. DBA exposure reduced cytokine production in spleen cell culture supernatants after in vitro stimulation with ConA or lipopolysaccharide (LPS). Immunosuppression was observed at lower doses in the holistic assays. The DTH response to Candida albicans was significantly decreased at 3.0?mg/?kg DBA, while the AFC response was intermittently suppressed at 1.0?mg/kg, with no effect observed at 0.3?mg/kg. These results demonstrate that a single pa of DBA produces systemic immunotoxicity, and of the assays utilized, the holistic assays (i.e., DTH, AFC) appear to be most sensitive to the immunosuppressive effects of DBA.     

Immunotoxicological profile of chloramine in female B6C3F1 mice when administered in the drinking water for 28 days

Monochloramine has been used to provide a disinfecting residual in water distribution systems where it is difficult to maintain an adequate free-chlorine residual or where disinfection by-product formation is of concern. The goal of this study was to characterize the immunotoxic effects of chloramine in female B₆C₃F₁ mice when administered via the drinking water. Mice were exposed to chloramine-containing deionized tap water at 2, 10, 20, 100, or 200?ppm for 28 days. No statistically significant differences in drinking water consumption, body weight, body weight gain, organ weights, or hematological parameters between the exposed and control animals were noted during the experimental period. There were no changes in the percentages and numbers of total B-lymphocytes, T-lymphocytes, CD4⁺ and CD8⁺ T-lymphocytes, natural killer (NK) cells, and macrophages in the spleen. Exposure to chloramine did not affect the IgM antibody-forming cell response to sheep red blood cells (SRBC) or anti-SRBC IgM antibody production. Minimal effects, judged to be biologically insignificant, were observed in the mixed-leukocyte response and NK activity. In conclusion, chloramine produced no toxicological and immunotoxic effects in female B₆C₃F₁ mice when administered for 28 days in the drinking water at concentrations ranging from 2–200?ppm.