Rob Bleumink

Ultrafine but not fine particulate matter causes airway inflammation and allergic airway sensitization to co‐administered antigen in mice

Background Airborne particulate matter (PM) is an important factor associated with the enhanced prevalence of respiratory allergy. The PM adjuvant activity on allergic sensitization is a possible mechanism of action involved, and the induction of airway inflammation is suggested to be of importance in PM‐induced adjuvant activity.

Concurrence of P450 1A induction and toxic effects in the mirror carp (Cyprinus carpio), after administration of allow dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin

Abstract Juvenile mirror carp ( Cyprinus carpio ) received a single i.p. injection of 0.01, 0.03, 0.05, 0.27, 0.57 and 2.93 μg 2,3,7,8-TCDD per kg body weight. Between 6 and 12 weeks after administration of the highest dose, a mortality of 60% was found. Growth was effected for the duration of the study. A decrease in food intake, severe cutaneous haemorrhages, apathetical behaviour, swollen gills and sunken eyes were observed at dose levels of 0.27 μg/kg and higher after 3 weeks. Decreases in the haemoglobin and haematocrit contents were observed 6 weeks after administration of the highest dose. Histopathological examination of the liver revealed fat depletion and pericholangitis at the two highest dose levels. In the spleen an increase in number of erythrocytes and melano-macrophage centres (MMCs) was observed at dose levels of 0.06 μg/kg and higher. Lymphocyte depletion occurred at dose levels above 0.27 μg TCDD/kg. A dose-related induction of 7-ethoxyresorufin- O -deethylation (EROD) activity was found after 1 week, with a hundred-fold induction 1 week after administration of a dose of 0.27 μg TCDD/kg and higher. After 3, 6 and 12 weeks maximal EROD induction was still observed. One week after treatment, the lowest dose significantly inducing EROD activity was 0.03 μg/kg and the ED50 was 0.048 ± 0.001 μ g/kg. In view of the high inducibility of the cytochrome P450 1A activity and the severe pathological symptoms at low dose levels, the mirror carp can be classified among the most sensitive species to TCDD.

Concurrence of P450 lAl induction and toxic effects after administration of a low dose of 2,3,7,8-tetrachlorodibenzo-P-dioxin (TCDD) in the rainbow trout (Oncorhynchus mykiss)

Abstract Juvenile rainbow trout received a single intraperitoneal injection of 0.006, 0.03, 0.06, 0.30, 0.60 or 3.06 μg 2,3,7,8-tetrachlorodibenzo-P-dioxin (TCDD)/kg body weight and were killed after three, six or twelve weeks. In the twelfth week after treatment of the highest dose. a 20% mortality was observed in the remaining fish of this dose group. Growth inhibition was noted six weeks after the highest dose. The relative liver weight did not show pronounced changes. However, histopathological evaluation revealed inflammation, single cell necrosis and sinusoidal dilatation. Three and six weeks after treatment the relative spleen weight showed an increasing trend, which might be attributed to congestion of erythrocytes. In addition lymphocyte depletion and congestion were observed from dose levels of 0.30 μg/kg. A dose related EROD (7-ethoxyresorufin O-deethylation activity was observed after three weeks, statistically significant from the controls at dose levels of 0.30 μg/kg or higher. The ED50 for EROD activity was established at 0.79 ± 0.49 ωg TCDD/kg. The total cytochrome P450 content parallels more or less the EROD activity. Thus a concomitant occurrence oftoxicological effects and P450 lAl induction were found at dose levels of 0.30 ωg/kg or higher, which classifies the rainbow trout among the more sensitive species for these type of compounds.

Activation of the Aryl Hydrocarbon Receptor Suppresses Sensitization in a Mouse Peanut Allergy Model

Food allergy is an increasing health problem in Western countries. Previously, it has been shown that the intensity of food allergic reactions can be regulated by regulatory T (T(reg)) cells. In addition, it has been shown that activation of the aryl hydrocarbon receptor (AhR) regulates T-cell responses by induction of T(reg) cells. Therefore, we hypothesized that activation of the AhR pathway can suppress development of food allergic responses through the induction of T(reg) cells. This was investigated by using a mouse model for peanut allergy. C3H/HeOuJ mice (AhR(b)(-2)) were sensitized to peanut by administering peanut extract (PE) by gavage in the presence of cholera toxin and were treated with the prototypical AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (0.6, 1.7, 5, and 15 μg/kg body weight) on days 3 and 11 orally. The functional role of CD4(+)CD25(+)Foxp3(+) T(reg) cells was investigated by depleting these cells with anti-CD25 mAb during sensitization to PE. TCDD treatment dose dependently suppressed sensitization to peanut (PE-specific IgE, IgG1, and IgG2a and PE-induced IL-5, IL-10, and IL-13, respectively). The percentage, but not the number, of CD4(+)CD25(+)Foxp3(+) T(reg) cells dose dependently increased by AhR activation in both spleen and mesenteric lymph nodes. Depletion of CD4(+)CD25(+)Foxp3(+) T(reg) cells markedly reversed the suppressive effect of TCDD on PE-specific antibody levels and PE-induced IL-5, IL-10, and IL-13 cytokine production. Present data demonstrate for the first time that activation of the AhR by TCDD suppressed the development of Th2-mediated food allergic responses. A functional shift within the CD4(+) cell population toward CD4(+)CD25(+)Foxp3(+) T(reg) cells appeared to underlie this effect. This suggests that the AhR pathway might provide potential therapeutic targets to treat food allergic diseases.

The role of intestinal dendritic cells subsets in the establishment of food allergy

Cite this as: J. J. Smit, M. Bol‐Schoenmakers, I. Hassing, D. Fiechter, L. Boon, R. Bleumink and R. H. H. Pieters, Clinical & Experimental Allergy, 2011 (41) 890–898.

Intestinal alkaline phosphatase contributes to the reduction of severe intestinal epithelial damage

Inflammatory bowel disease is characterized by chronic inflammation of the intestine and is accompanied by damage of the epithelial lining and by undesired immune responses towards enteric bacteria. It has been demonstrated that intestinal alkaline phosphatase (iAP) protects against the induction of inflammation, possibly due to dephosphorylation of lipopolysaccharide (LPS). The present study investigated the therapeutic potential of iAP in intestinal inflammation and epithelial damage. Intestinal epithelial damage was induced in C57BL/6 mice using detran sulfate sodium (DSS) and iAP was administered 4days after initial DSS exposure. Loss in body weight was significantly less in iAP-treated mice and accompanied with reduced colon damage (determined by combination of crypt loss, loss of goblet cells, oedema and infiltrations of neutrophils). Treatment with iAP was more effective in case of severe inflammation compared to situations of mild to moderate inflammation. Rectal administration of LPS into a moderate inflamed colon did not aggravate inflammation. Furthermore, soluble iAP did not lower LPS-induced nuclear factor-kappaB activation in epithelial cells in vitro but induction of cellular AP expression by butyrate resulted in decreased LPS response. In conclusion, the present study shows that oral iAP administration has beneficial effects in situations of severe intestinal epithelial damage, whereas in moderate inflammation endogenous iAP may be sufficient to counteract disease-aggravating effects of LPS. An approach including iAP treatment holds a therapeutic promise in case of severe inflammatory bowel disease.

Effects of Supplementation With Vitamins A, C, and E, Selenium, and Zinc on Immune Function in a Murine Sensitization Model

OBJECTIVE We compared the effects of supplementing with vitamins A, C, and E, selenium, and zinc on a range of innate and specific T-helper 1 (Th1) and Th2-driven adaptive immune responses. METHODS BALB/c mice were fed semi-purified AIN93 diets and randomly assigned to receive a diet supplemented with 120 mg/kg of vitamin A, 2500 mg/kg of vitamin C, 1000 mg/kg of vitamin E, 2 mg/kg of selenium, and 500 mg/kg of zinc (n = 15/group). After 4 wk of supplementation, mice were sensitized by topical application of di-nitro-chlorobenzene (DNCB); 2 wk later mice were challenged; and 5 d later they were killed to assess the effect on a range of innate responses (phagocytic activity, oxidative burst and tumor necrosis factor-alpha), adaptive Th1-driven responses (delayed-type hypersensitivity, DNCB-specific immunoglobulin [Ig] G2a and IgG2b, and interferon-gamma [IFN-gamma]), and adaptive Th2-driven responses (DNCB-specific IgE and IgG1 and interleukin-4 [IL-4]). RESULTS Immune function was affected only in the vitamin A group. These mice gained less weight and were less capable of resolving the inflammatory response elicited during sensitization. The oxidative burst of blood cells was increased, but production of IFN-gamma and IL-4 and the ratio of IFN-gamma to IL-4 were markedly depressed. In concordance with the latter result, production of Th1-driven IgG2a antibodies was decreased, whereas Th2-driven isotypes were not affected (IgG1, IgE) and mucosal IgA was increased. CONCLUSIONS These findings confirmed that supplementary amounts of vitamin A above dietary requirements enhance inflammatory responses accompanied by decreased Th1 and increased mucosal responses. However, supplementation of these sufficiently fed, non-stressed, young adult mice with vitamins C and E, selenium, or zinc had no effect on immune function. We speculate that using this model in aged, physiologically, or nutritionally stressed mice may provide outcomes more similar to those in sensitive human populations. If so, this would improve the usefulness of the model to assess, characterize, and rank effects of foods or nutrients on a range of immune functions, including Th1/Th2 polarization.

Regulation by intestinal γδ T cells during establishment of food allergic sensitization in mice

To cite this article: Bol‐Schoenmakers M, Marcondes Rezende M, Bleumink R, Boon L, Man S, Hassing I, Fiechter D, Pieters RHH, Smit JJ. Regulation by intestinal γδ T cells during establishment of food allergic sensitization in mice. Allergy 2011; 66: 331–340.

Selective immunomodulation by the autoimmunity-inducing xenobiotics streptozotocin and HgCl2.

Exposure to certain drugs and environmental chemicals can provoke the onset of autoimmune disease in susceptible individuals by releasing (self) epitopes for which tolerance has not been established, while simultaneously providing the necessary adjuvant activity. The resulting response type is influenced by the genotype of exposed individuals and relates to susceptibility to the adverse immune effects of the chemicals. Here, we assessed the modulatory role of the chemical compounds themselves. A single injection of streptozotocin (STZ) increased the number of CD8+ cells, macrophages, apoptotic cells, and IFN‐γ‐producing T  helper and T cytotoxic cells, whereas the number of CD4+ cells and B cells was reduced in the draining lymphnode. Coinjection with the reporter antigen TNP‐OVA resulted in primary and secondary production of TNP‐specific antibodies that were predominantly of IgG2a and IgG2b isotype, whereas STZ did not enhance priming for delayed‐type hypersensitivity (DTH) responses to TNP‐OVA. Injection of HgCl2 on the other hand, reduced the number of IFN‐γ‐producing cells, induced accumulation of B cells and CD4+ and CD8+ T cells, enhanced IgG1 and IgE production to TNP‐OVA, and primed for secondary IgG1 and IgE production as well as for DTH reactions. Together these results indicate that a single injection of STZ stimulates type‐1 responses, whereas HgCl2 enhanced mixed type‐1 and −2 responses in BALB/c mice. These response types match the (auto)immune effects elicited to unknown (auto)antigens following multiple injections of these chemicals.

Selective Requirement for CD40-CD154 in Drug-Induced Type 1 Versus Type 2 Responses to Trinitrophenyl-Ovalbumin

CD154 is transiently expressed by activated T cells and interacts with CD40 on B cells, dendritic cells, macrophages, and monocytes. This costimulatory receptor-ligand couple seems decisive in Ag-driven immune responses but may be differentially involved in type 1 vs type 2 responses. We studied the importance of CD40-CD154 in both responses using the reporter Ag popliteal lymph node assay in which selectively acting drugs generate clearly polarized type 1 (streptozotocin) or type 2 (D-penicillamine, diphenylhydantoin) responses to a constant coinjected Ag in the same mouse strain. Treatment of mice with anti-CD154 reduced characteristic immunological parameters in type 2 responses (B and CD4+ T cell proliferation, IgG1 and IgE Abs, and IL-4 secretion) and only slightly affected the type 1 response (small decrease in IFN-γ production, influx of CD11c+ and F4/80+ cells, and prevention of architectural disruption of the lymph node, but no effect on IgG2a Ab and TNF-α secretion or B and CD4+ T cell proliferation). The findings indicate that the CD40-CD154 costimulatory interaction is a prerequisite in drug-induced type 2 responses and is only marginally involved in type 1 responses. The observed expression patterns of CD80 and CD86 on different APC (B cells in type 2 and dendritic cells in type 1) may be responsible for this discrepancy.