Immunological determinants of ventilatory changes induced in mice by dermal sensitization and respiratory challenge with toluene diisocyanate

University of Leuven, Louvain, Flemish, Belgium
AJP Lung Cellular and Molecular Physiology (Impact Factor: 4.08). 02/2007; 292(1):L207-14. DOI: 10.1152/ajplung.00157.2005
Source: PubMed


The objective of the study was to characterize better the immunologic mechanisms underlying a previously developed animal model of chemical-induced asthma. BALB/c and severe combined immunodeficiency disease (SCID) mice received toluene diisocyanate (TDI) or vehicle on each ear on day 1 and/or day 7. On day 10, they were intranasally challenged with TDI or vehicle. Ventilatory function was monitored by whole body plethysmography for 40 min after challenge. Reactivity to methacholine was measured 23 h later: enhanced pause and actual resistance measurements. Pulmonary inflammation was assessed 1, 6, and 24 h after challenge by bronchoalveolar lavage (BAL). Tumor necrosis factor-alpha and macrophage inflammatory protein (MIP)-2 levels were measured in BAL. Immunological parameters included total IgE, IgG1, and IgG2a in serum, lymphocyte populations in auricular and cervical lymph nodes, and IL-4 and IFN-gamma levels in supernatants of lymph node cells, cultured with or without concanavalin A. Ventilatory changes suggestive of airway obstruction and increased methacholine reactivity were observed in all TDI-sensitized and TDI intranasally instilled mice, except in SCID mice. A neutrophil influx, accompanied by an increase in MIP-2 levels, was found in BAL of all responding groups 6 and 24 h after intranasal challenge. In BALB/c mice an increased level of CD19+ B cells was found in the auricular lymph nodes. IL-4 and IFN-gamma levels were increased in supernatants of concanavalin A-stimulated auricular lymph node cells from BALB/c mice completely treated with TDI. These results indicate that our model is dependent on the presence of lymphocytes, but it is not characterized by a preferential stimulation of Th1 or Th2 lymphocytes.

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Available from: Jeroen Vanoirbeek
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    • "Additionally, MIP-2 has been shown to apparently reduce mycobacterial-induced recruitment of neutrophils [53]. Previous studies have shown that MIP-2 rose in TDI-induced asthma [54] [55]. Also, an influx of neutrophils, accompanied by a marked increase in MIP-2 level, was found in BAL of TDI group in the present study. "
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    ABSTRACT: Diisocyanates are one of the leading causes of occupational asthma, which is dominated by granulocytic inflammation in the airway. In this study, we intended to explore the role of ethyl pyruvate (EP) on neutrophil infiltration in a toluene-2,4-diisocyanate (TDI)-induced murine asthma model. The experimental mice were first dermally sensitized and then challenged with TDI via oropharyngeal aspiration. The mice were treated intraperitoneally with 100, 50 or 10mg/kg EP 1h before each challenge. One day after the last challenge, airway reactivity to methacholine was measured by a barometric plethysmographic chamber. Total and differential cell counts, along with levels of macrophage inflammatory protein-2 (MIP-2), TNF-α in bronchoalveolar lavage (BAL) fluid and mRNA expression of CXCR2 in the lung were assessed. To depict neutrophils, a naphthol AS-D chloroacetate esterase kit was used. High mobility group box 1 (HMGB1) was determined by western blot and immunohistochemistry. Treatment with EP dramatically decreased airway hyperresponsiveness in TDI-challenged mice, as well as numbers of neutrophils in BAL fluid and peribronchovascular regions. Both the TDI-induced raised protein level and abnormal distribution of HMGB1 were significantly recovered by EP in a dose-dependent manner. The concentration of MIP-2 in TDI-induced asthma mice was significantly higher than that of the control ones, while EP had few effects on MIP-2. The mRNA expression of CXCR2 didn't change significantly, and TNF-α was not detected in BAL fluids. EP reduces airway neutrophil infiltration partly through downregulating HMGB1 in a chemical-induced murine asthma model.
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    • "Previously, inhalation was identified as the most likely route of exposure, however, increasingly, the dermal route of dNCO sensitization has been of concern (Redlich, 2010). Using animal models, it has been demonstrated that dermal sensitization prior to intranasal challenge influences sensitization to TDI (De Vooght et al., 2010; Nabe et al., 2005; Tarkowski et al., 2007; Vanoirbeek et al., 2003, 2004), and may induce a Th 2 immune response (Ban et al., 2006). "
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    ABSTRACT: Diisocyanates (dNCOs) are potent chemical allergens utilized in various industries. It has been proposed that skin exposure to dNCOs produces immune sensitization leading to work-related asthma and allergic disease. We examined dNCOs sensitization by using a dermal murine model of toluene diisocyanate (TDI) exposure to characterize the disposition of TDI in the skin, identify the predominant haptenated proteins, and discern the associated antigen uptake by dendritic cells. Ears of BALB/c mice were dosed once with TDI (0.1% or 4% v/v acetone). Ears and draining lymph nodes were excised at selected time points between 1 hr and 15 days post-exposure and were processed for histological, immunohistochemical, and proteomic analyses. Monoclonal antibodies specific for TDI-haptenated protein (TDI-hp) and antibodies to various cell markers were utilized with confocal microscopy to determine co-localization patterns. Histopathological changes were observed following exposure in ear tissue of mice dosed with 4% TDI/acetone. Immunohistochemical staining demonstrated TDI-hp localization in the stratum corneum, hair follicles and sebaceous glands. TDI-hp were co-localized with CD11b(+) (integrin αM/Mac-1), CD207(+) (langerin), CD103(+) (integrin αE) cells in the hair follicles and in sebaceous glands. TDI-hp were also identified in the draining lymph nodes (DLN) 1 hr post exposure. Cytoskeletal and cuticular keratins along with mouse serum albumin were identified as major haptenated species in the skin. The results of this study demonstrate that the stratum corneum, hair follicles and associated sebaceous glands in mice are dendritic cell accessible reservoirs for TDI-hp and thus identify a mechanism for immune recognition following epicutaneous exposure to TDI.
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    • "Third, B-lymphocytes from lymph nodes of TDI-sensitized mice were transferred into naïve SCID mice. Previously, we had shown that SCID mice are not able to develop an asthma-like response after dermal sensitization and challenge with TDI [15]. However, after transferring B-lymphocytes obtained from TDI-sensitized mice into naïve SCID mice a significant increase in airway reactivity (Figure 3 F) and airway inflammation (Figure 3 G) was found after TDI challenge. "
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