Immunological determinants in a mouse model of chemical-induced asthma after multiple exposures.

In a mouse model of chemical-induced asthma, we investigated the effects of multiple challenges, using toluene diisocyanate (TDI), a known cause of occupational asthma. On days 1 and 7, BALB/c mice received TDI or vehicle (acetone/olive oil). On days 10, 13 and 16 the mice received an intranasal instillation of TDI. Ventilatory function (Penh) was monitored by whole body plethysmography for 40 min after each challenge. Reactivity to methacholine was measured 22 h later. Pulmonary inflammation, TNF-alpha and MIP-2 levels were assessed 24 h after the last challenge by broncho-alveolar lavage (BAL). Other immunological parameters included total IgE, lymphocyte sub-populations in auricular and cervical lymph nodes, and IL-4, IFN-gamma and IL-13 levels in supernatants of lymph node cells, cultured with or without concanavalin A. Early ventilatory function and airway reactivity increased in all groups that received a dermal application and one or multiple intranasal challenges of TDI. After multiple challenges, lung inflammation was characterized by neutrophils (approximately 15%), and eosinophils (approximately 4%), along with an increase in BAL MIP-2 and TNF-alpha levels. The auricular and cervical lymph node cells of all sensitized mice showed an increase in B cells, Th cells and an increased concentration of in vitro release of IL-4, IFN-gamma and IL-13 after stimulation with concanavalin A. Total serum IgE was elevated in dermally TDI-sensitized mice. This protocol including multiple challenges results in a model that resembles human asthma, indicating that responses found in the model using a single challenge could be a good first indication for the development of asthma.

Immune effects and exposure to ethylenebisdithiocarbamate pesticides in re-entry workers in the Netherlands.

Ethylenebisdithiocarbamates are widely used as fungicides in agriculture. Although EBDC's have a low acute toxicity, they are suspected to have immune effects at low doses. However, little human studies on these effects have been published. In the Netherlands, a study was conducted among pesticide exposed workers aimed at evaluating the short-term and long-term immune effects of exposure and the relation between ethylenebisdithiocarbamate and immune effects. Forty-one re-entry workers and 40 nonexposed controls were medically examined; furthermore, immune parameters were determined in blood, and all participants filled in a questionnaire regarding exposure and outcome parameters. The level of ethylenethiourea in urine was determined as indicator of exposure. No relevant adverse immune effects were found in the pesticide exposed workers compared with the nonexposed controls. Also no exposure response relationship between immune effects and ethylenebisdithiocarbamate in urine was found. This finding might be due to very low exposure levels of the re-entry work but might also be due to a lack of immunotoxicity of ethylenebisdithiocarbamate at normal exposure levels.

Asthmatic symptoms after exposure to ethylenebisdithiocarbamates and other pesticides in the Europit field studies.

We conducted a multicenter prospective study to assess the effects of occupational exposure to ethylenebisdithiocarbamate fungicides and/or other pesticides on self-reported asthma and asthmatic symptoms. This multicenter study was conducted among 248 workers exposed to pesticides and 231 non-exposed workers from five field studies. The five field studies were carried out in The Netherlands, Italy, Finland, and two studies in Bulgaria. Subjects constituting this cohort completed a self-administered questionnaire at baseline (before the start of exposure). Ethylenethiourea in urine was determined to assess exposure to ethylenebisdithiocarbamates. In multivariate analyses adjusted for all potential confounders (age, education, residence, smoking, gender, and field study), we found inverse associations, all not statistically significant, between occupational exposure to pesticides and asthma diagnosis (OR 0.41; 95% CI 0.15-1.11), complains of chest tightness (OR 0.60; 95% CI 0.36-1.02), wheeze (OR 0.56; 95% CI 0.32-0.98), asthma attack (OR 0.52; 95% CI 0.12-2.25), and asthma medication (OR 0.79; 95% CI 0.25-2.53). Furthermore, we reported null associations for multivariate analysis using ethylenethiourea as determinant for exposure. Although exposure to pesticides remains a potential health risk, our results do not suggest an association between exposure to ethylenebisdithiocarbamates and/or other pesticides used in our study on asthma and asthmatic symptoms.

The effect of IL-18 on IL-12-induced CD30 expression and IL-4 and IFN-gamma production by allergen and PPD specific T cells.

CD30 is expressed on activated T cells that, as has been suggested, preferentially produce IFN-gamma. Interleukin 12 increases antigen-induced CD30 expression on T cells and IFN-gamma production. Synthesis of IFN-gamma can be augmented further by IL-18. The aim of our study was to investigate whether IL-18 affects the IL-12 induced CD30 expression and cytokine production by allergen or PPD specific T cells. Mononuclear cells of healthy or atopic volunteers were stimulated with PPD or allergen, respectively, to obtain specific T cell lines. T cells were restimulated with appropriate antigen and antigen-presenting cells in the presence of IL-12, IL-18 or a combination of these cytokines. After 3 days, expression of CD30 was investigated on CD4 and CD8 T cells and IFN-gamma and IL-4 cytokine production was estimated in the culture supernatants. Flow cytometric analyses showed no effect of IL-18 on CD30 expression during IL-12 co-stimulation. At the same time after the optimal stimulation for CD30 expression, the levels of IFN-gamma were high in PPD-stimulated cell lines but have not been up-regulated by IL-18. IFN-gamma levels were much lower in allergen-stimulated T cells and although they were up-regulated by IL-12 there was no additional or synergistic effect from IL-18. IL-18, however, increased production of IL-4 in allergen-stimulated cell lines. Our studies provide new information about IL-18 activity on human cells and question its exclusive role in Th1 mediated responses.

The influence of diesel exhaust particles on mononuclear phagocytic cell-derived cytokines: IL-10, TGF-beta and IL-1 beta.

Diesel exhaust particles (DEP) are known to modulate the production of cytokines associated with acute and chronic respiratory symptoms and allergic respiratory disease. Tolerance is an important mechanism through which the immune system can maintain nonresponsiveness to common environmental antigens. We examined the effect of DEP on IL-10 and TGF-beta, cytokines produced by macrophages and repressor (Tr-like) lymphocytes which influence tolerance. Human PBMCs (n = 22) were incubated with 1-100 ng/ml of DEP, and suboptimally primed with LPS. IL-10 gene expression was assessed by the S1 nuclease protection assay, and production of IL-10, TGF-beta, TNF-alpha, IL-1 beta and IL-4 stimulated CD23 was evaluated by ELISA after 24 and 48 h. The effect of the order of exposure to DEP and LPS was evaluated on IL-10 protein and mRNA in cells (1) preincubated with LPS followed by DEP, or (2) exposed first to DEP followed by LPS. IL-10 was further evaluated using benzo[a]pyrene and [alpha]naphthoflavone as a surrogate for the polyaromatic hydrocarbons (PAHs) adsorbed to DEP. Control cells were incubated with carbon black, without PAHs. In PBMCs exposed to DEP with LPS, or preincubated with LPS before DEP, IL-10 production and mRNA fall significantly. TGF-beta is similarly suppressed, IL-1 beta secretion is significantly stimulated, and IL-4 stimulated CD23 release rises in the atopic subjects. In contrast, when DEP is added prior to LPS, IL-10 production rises, and IL-1 beta falls to zero. These effects on IL-10 are reproduced with benzo[a]pyrene and reversed by the coaddition of [alpha]naphthoflavone, its known antagonist. The carbon black fraction has no effect on IL-10 production. The effect of DEP on IL-10 can be inhibitory or stimulatory, depending on the order of exposure to DEP and LPS. Pro-inflammatory cytokines and factors rise when IL-10 is inhibited, and are suppressed when IL-10 is stimulated. These results are duplicated with benzo[a]pyrene, suggesting that the PAH portion of the DEP is the active agent.

[Psychoneuroimmunology. A new approach to the function of immunological system]. / Psychoneuroimmunologia. Nowe spojrzenie na funkcjonowanie ukladu odpornosciowego.

The most recent evidence suggests that the immune system responses are not regulated only by the presence of antigens but they are also influenced by the brain and behavior. It has been known for some time that stressful conditions alter the functioning of the immune system. Despite methodological difficulties in the quantitation of stress, and its association with the onset of illness, the concept of the stress impact on susceptibility to several diseases is widely acknowledged. This paper reviews the effects of stress on the endocrine and central nervous systems and presents the interactions between these systems and the immune response after exposure to stress signals.

[Genetic polymorphism of glutathione s-transferase as a factor predisposing to allergic dermatitis]. / Polimorfizm genetyczny s-transferaz glutationowych jako czynnik predysponujacy do wystapienia alergii skórnej.

In the inductive phase of contact allergic dermatitis, simple chemical compounds (haptens) produce together with epidermic proteins adducts presented by Langerhans cells to T lymphocytes. Binding to protein carrier is a necessary condition of transforming a low-molecular allergen into immunogenic one and evoking immunological reaction. The production of allergen adducts with proteins is conditioned by the presence of electrophilic groups in their molecules, or their acquiring during biotransformation phase I. Active allergen metabolites undergo further alterations during biotransformation phase II which leads most frequently to the decline in their chemical activity and more rapid excretion from the body. The number of reactive metabolites (reactive allergens) available for producing adducts with proteins keeps the balance between activation and deactivation reactions. Glutathione S-transferases play a particular role in the allergens (or their metabolites) deactivation process in biotransformation phase II. These enzymes catalyse reactions responsible for the declined electrophilic potential of allergens (or their metabolites), and thus for the decrease in the number of allergen molecules able to produce protein covalent bindings (adducts). Glutathione S-transferases, occurring in the human cellular cytoplasm belong to five classes: alpha(GST A), mu(GST M), theta(GST P), pi(GST T) and Z(GST Z), as well as to one class present in microsomes. The study indicated the presence of isoenzymes GST T1 and GST M1 in the skin. Both isoforms participate in the process of low-molecular allergen biotransformation. Carriers of defective genes GST T1 and/or GST M1 are more vulnerable to allergenic effect of some allergens, e.g. thimerosal, which is associated with the absence of or decrease in the activity of isoenzymes GST T1 and GST M1.

The effect of antigen stimulation on alpha(4), beta(1) and beta(7) chain integrin expression and function in CD4+ cells.

BACKGROUND: The alpha(4) integrin, as alpha(4)beta(1) (VLA-4) or alpha(4)beta(7), is critical for T cell migration and proliferation, although its functional modulation remains poorly understood. We hypothesized that increased receptor density, based on new receptor chain synthesis, was one such mechanism. We examined the surface receptor density of the alpha(4) and beta(1) chains on CD4+CD45RO+ cells, and the mRNA expression of these and the beta(7) chain in response to allergen and nonallergen antigen stimulation. METHODS: Flow-cytometric analyses for CD49d, CD29, and CD45RO were performed on T cell lines specific for timothy, tetanus, and Candida from atopic and nonatopic donors. RNA was extracted from cells sorted to select CD4+/CD49d-positive cells before and after stimulation. Equivalent amounts of cDNA for beta-actin, alpha(4), beta(1) and beta(7) were used in PCR, and the products were quantified using phosphoimaging. RESULTS: CD49d expression is heterogeneous on T cell lines and is upregulated by antigen stimulation on CD4+ T cells. The surface expression on CD4+CD45RO+ timothy allergen or tetanus toxoid T cell lines is at least double that found on CD45RO- cells. Antigen stimulation upregulated CD49d expression on the CD4+CD45RO+ subpopulation of both cell lines although it was not as significant as in the case of all CD4+ T cells. CD29 surface expression behaves similarly. Candida had no effect on CD49d or CD29. Messenger RNA expression for the alpha(4) chain (CD49d) is significantly upregulated 48 h following the addition of timothy or tetanus. beta(7) chain expression also rises significantly on both cell lines. beta(1) chain expression increases, but not significantly. CONCLUSIONS: The surface expression of the CD49d is heterogeneous and much higher on CD4+CD45RO+ cells than on CD4+RO- T cells. The CD49d integrin chain on CD4+ T cells is upregulated following antigen exposure. However, the CD4+CD45RO+ subpopulation is only partially responsible for this increase suggesting other T cells to have this receptor expression upregulated. CD29 expression behaves similarly. Messenger RNA expression increases coordinately for alpha(4), beta(7), and not significantly for beta(1) in these cells. These observations provide a potential mechanism for the selective accumulation of T cells at sites of inflammation, and suggest an important point of intervention for allergic and inflammatory disease.

Expression and function of CD30 on T lymphocytes.

T cell receptor, accessory molecules, cytokines are important regulatory factors that determine the development and function of T lymphocytes. Among them are also molecules belonging to superfamily of tumor necrosis factor receptor (TNFR) which beside CD30 include CD27, CD40, TNFR-I and -II, Fas (CD95), OX40, 4-1BB (CDw137), nerve growth factor receptor, lymphotoxin-beta receptor, Apo3/DR3/Ws1-1/lymphocyte associated receptor of death, DR4, DR5/TNF-related apoptosis-inducing ligand, osteoprotegerin, and TNFR-related 2. CD30 recognized originally on Reed-Sternberg cells of Hodgkin's lymphoma became of interest in studies of Th1 and Th2 cell differentiation. This paper shows recent findings regarding CD30 expression and its pleiotropic role in T cell function. It provides information about controversial role of CD30 as Th2 cell differentiation marker and gives concise insight into the function of this receptor as a signal transducing molecule.

CD49d expression and function on allergen-stimulated T cells from blood and airway.

The alpha4 chain (CD49d), which constitutes one of the chains of alpha4beta1 (very late activating antigen-4 [VLA-4]) and alpha4beta7 integrins, mediates migration of T cells to extravascular spaces. The interaction between VLA-4 and vascular cell adhesion molecule-1 (VCAM-1) has been shown to be the critical pathway for the selective accumulation of eosinophils and basophils at sites of allergic inflammation. T lymphocytes are also specifically recruited into allergic sites, including the allergic asthmatic airway. Increased numbers of activated CD4+ cells expressing the DR antigen subset of the human leukocyte antigens (HLA-DR) appear in the allergic lung 48 h after allergen inhalation. The mechanisms by which these cells localize into the lung are still unknown. We report that stimulation of allergen-specific T cells with allergen in vitro resulted in enhanced expression of alpha4 chain (CD49d) as measured by receptor density on allergen-specific T-cell lines and T-cell clones. Kinetic studies showed that CD49d density was enhanced over a 24- to 48-h period in a time-dependent fashion, and was coordinately upregulated with HLA-DR expression. We also demonstrated that increased expression of CD49d on T-cell lines 24 h and 48 h after stimulation correlated with increased adhesion to the CS-1 fragment of fibronectin. In contrast, lymphocyte function-associated antigen-1b (LFA-1b) (CD11b), LFA-3 (CD58), and intercellular adhesion molecule-1 (ICAM-1) (CD54) expression did not change with allergen stimulation. We also showed that CD49d receptor density on T cells obtained by bronchoalveolar lavage (BAL) of allergic patients before and 48 h after allergen challenge was significantly higher than that on T cells taken from BAL of normal subjects and from controls with other inflammatory lung diseases. Taken together, these findings indicate that allergen stimulation activates allergen-specific T cells and coordinately induces increased CD49d receptor expression and binding to counterligands. We postulate that allergen-driven upregulation of CD49d, which together with the beta1 chain constitutes VLA-4 integrin, may be responsible for the selective accumulation of T cells in the allergic asthmatic lung.

Increased IgE antiovalbumin level in mice exposed to formaldehyde.

The effect of formaldehyde exposure on the sensitization of mice to ovalbumin was investigated. Significantly increased IgE antiovalbumin titers were found in mice sensitized intranasally to ovalbumin and exposed for 10 days to 2 mg/m3 of formaldehyde. In contrast, mice not exposed to formaldehyde or exposed once a week produced low levels of this antibody. The exposure of mice, sensitized intraperitoneally with ovalbumin, to formaldehyde did not increase sensitization. It was concluded that formaldehyde facilitates sensitization of mice to ovalbumin by changes that occur in the respiratory tract.

Non specific environmental factors and asthma development.

Environmental pollutants seem to be responsible for dramatical increase of allergic disorders that have been observed lately. The best documented environmental factors facilitating allergy development are: ozone, diesel-exhaust particulate matter and tobacco smoke. Formaldehyde and SO2 seem to be also very important but still are not sufficiently documented. Mechanisms involved in allergy promotion include: better penetration of allergens across respiratory mucosa or direct modulation of immunological response.

Neutrophil chemiluminescence following exposure to formaldehyde in healthy subjects and in patients with contact dermatitis.

13 formaldehyde-sensitive contact dermatitis patients and 5 healthy subjects were exposed to formaldehyde (FM) at a concentration 0.5 mg/m3, in an exposure chamber for 2 hours. There was no significant decrease of the ventilatory parameters either in healthy subjects or in contact dermatitis patients following the exposure Bronchial hyperreactivity to histamine (PC20) increased in one healthy and two patients with contact dermatitis. Neutrophils were isolated from whole venous blood before the test and 30 minutes and 24 hours after the exposure. All subjects with allergic contact dermatitis had chemiluminescence higher before the FM provocation in a comparison with the healthy ones. It increased significantly 30 minutes post the exposure and was much higher 24 hours after the exposure in the comparison with the neutrophil chemiluminescence before the test.

Macrophage activity in asbestos related diseases.

This paper indicates some immunological aspects of asbestos-related diseases and especially concerns the activity of macrophages--cells of immunological surveillance. Macrophages establish a very important population of cells which initiate or suppress specific immune response; they are responsible for effective T-cell activation, express antitumour activity. The process of lung fibrosis generated by the inhalation and deposition of asbestos fibres is also closely related to macrophage activity. An open question which is still to be resolved concerns asbestos-induced fibrosis; it may arise as a consequence of tissue injury and repair or change collagen synthesis. Another question is, to what extent macrophages may be protective cells and when they become undesirable? Since their overstimulation or damage in the case of chronic exposure to asbestos dust may be the reason of the increased release of inflammatory mediators, reactive oxygen intermediates which may in turn cause tissue injury, fibrosis or, in final effect, cancer. If so, we could then say that lung response (expressed by e.g. alveolar macrophage activity) to chemical insult may cause further damage to this tissue.