J. Garssen

Previously, maternal supplementation with short-chain galacto- and long-chain fructo-oligosaccharides (scGOS/lcFOS; ratio 9:1) was shown to affect maternal and fetal immune status in mice. This study was designed to test the long-term effects of supplementation of mice with scGOS/lcFOS before and during pregnancy on the immune response in the offspring, using an ovalbumin (OVA)-induced model for experimental allergic asthma. Female Balb/c mice were fed a control diet or a diet supplemented with 3% scGOS/lcFOS and mated to C57BL/6 males. All dams were fed the control diet after delivery. At 6 wk, male offspring received an intraperitoneal injection of aluminum hydroxide and OVA (control and scGOS/lcFOS group) or saline (sham group). The acute allergic skin response (ASR) after intradermal challenge with OVA or saline was measured at 8 wk. After 3 airway challenges with nebulized OVA or saline, lung function was measured. The scGOS/lcFOS group had a significantly lower acute ASR (85 ±...

We previously demonstrated that tracheal hyperreactivity (in vitro) and altered lung functions (in vivo) were induced during a delayed-type hypersensitivity (DTH) reaction in murine lungs. These alterations were transferable with T cells, suggesting that this animal model could be used as a model for cellular IgE-independent immunity. In the present study we demonstrated that depletion of T suppressor/cytotoxic cells failed to abolish the ability of transferred cells to induce hyperresponsiveness. Depletion of T helper cells partially inhibited the induction of hyperreactivity. Depletion of 14-30+ cells (the monoclonal antibody 14-30 reacts with a common isotype of T cell-derived antigen binding molecules [TABM] that can arm mast cells) completely abolished the ability to transfer hyperreactivity. The cromoglycate-like antiasthmatic drug nedocromil, which stabilizes mast cells, inhibited the induction of T cell-mediated hyperresponsiveness. Moreover, in mast cell-deficient mice, T cell-mediated hyperresponsiveness can be less induced compared with normal littermates. These experiments indicate that mast cells play at least a partial role in the induction of airway hyperresponsiveness in this model. Dexamethasone, a well-known inhibitor of phospholipase A2, inhibited the T cell-mediated hyperresponsiveness, whereas the cyclooxygenase inhibitor suprofen did not. This indicated that arachidonic acid metabolites, but not cyclooxygenase products, play a role in the induction of T cell-mediated hyperreactivity. Pretreatment with the lipoxygenase inhibitor AA-861 significantly inhibited the induction of tracheal hyperreactivity. Platelet-activating factor appeared not to be involved in the induction of hyperresponsiveness in this model, because the platelet-activating factor antagonist WEB 2170 failed to abolish the induction of T cell-mediated hyperreactivity. Intravenous injection of purified mast cell-arming TABM, followed by intranasal hapten challenge 30 min later, resulted in increased vascular permeability 2 h after challenge, which is characteristic of the early initiating phase of DTH. In addition, tracheal hyperreactivity (in vitro) and altered lung functions (in vivo) were observed 2 h after challenge. From these data we conclude that airway hyperreactivity and altered lung functions are induced by early steps in the cellular cascade of DTH.

Toluene diisocyanate (TDI) is a low-molecular-weight compound which is known to cause occupational asthma in 5 to 10% of exposed workers. Previously, we developed a murine model to investigate TDI-induced occupational asthma. Short-term exposure to TDI (skin sensitization twice daily on Day 0 and Day 1 and intranasal challenge on Day 8) led to a nonspecific tracheal hyperractivity 24 h after the challenge in TDI-sensitized mice when compared with nonsensitized mice whereas no TDI-specific IgE antibodies were found in the serum. Because 20% of subjects with TDI-induced occupational asthma exhibit an increase in serum IgE antibodies, we exposed mice for a longer period of time to investigate whether this procedure could induce TDI-specific antibody production in exposed mice. Long-term exposure (skin sensitization on 6 consecutive weeks followed by intranasal challenge on Week 7) resulted in the production of total IgE and IgG and TDI-specific IgE and IgG antibodies. Airway reactivity to various agonists was also measured in vitro and in vivo in long-term exposed mice. TDI-sensitized mice exhibited in vitro tracheal hyperreactivity to carbachol 3 h after the challenge when compared with the nonsensitized mice. Moreover, in vivo airway hyperresponsiveness to serotonin (5-hydroxytryptamine [5HT]) was found 3 h after the challenge in TDI-sensitized mice. Interestingly, in vivo airway hyperresponsiveness was not observed at any time point in the mice exposed to TDI according to the short-term protocol. In conclusion, by altering the exposure time and/or cumulative dosage of TDI different biological reactions can be elicited in exposed mice. This important finding might be a reflection of the diversity of symptoms found in patients suffering from TDI-induced asthma. Both the short-exposure and the long-exposure model will be useful to further investigate the mechanisms of action of TDI.

Background: Oligosaccharides may support postnatal immune development by influencing the constitution of gastrointestinal microbiota. This prospective, double-blind, randomised, placebo controlled trial investigated the effect of a specific prebiotic mixture of short chain galactooligosaccharides (scGOS) and long chain fructooligosaccharides (lcFOS) on microbiota and immune biomarkers during the first six months of life in high risk infants for allergies fed a formula based on intact cow's milk protein. Methods: If formula feeding was started, the infant was randomly assigned to one of two cow's milk formula groups (0.8 g/100 ml scGOS/lcFOS or maltodextrine as control). The faecal microbiota of the scGOS/lcFOS and control groups was analysed. In a subgroup blood was collected at the age of six months for serum biomarkers. A reference group consisted of 90 exclusively breast fed infants up to six months of age. Results: In both the prebiotic group and control group a total of...

It is known that ultraviolet-B light (UV-B) affects human health. In addition to deleterious effects on the skin and the eyes, such as erythema, photoageing, keratitis and cataract, UV-B is also able to impair the resistance against skin-associated tumours and infections. Our data implicate that UV-B can impair the resistance against certain non-skin-associated infections in rats, such as Listeria monocytogenes, Trichinella spiralis and Ratcytomegalovirus (RCMV). Rats, infected with T. spiralis, had an increased amount of T. spiralis larvae in their carcasses after UV-B exposure in comparison to control animals, indicating that the resistance to this parasite was decreased by UV-B. Exposure to UV-B caused an increase of RCMV load in the salivary gland 26 days after infection with this virus, indicating that especially the resistance against the second generation of viruses was impaired. In L. monocytogenes-infected rats, UV-B exposure caused an increased number of bacteria in the spleen, coupled to a decreased specific response of T lymphocytes to the bacteria. We conclude that UV-B radiation may affect the resistance against several non-skin-associated infectious diseases, which is probably caused by a defect in the specific lymphocyte response to the antigen.

Airway hyperreactivity is an almost universal feature of asthma. The origin of this phenomenon is poorly understood. Although a role has been suggested for cell-mediated immune responses in the induction of bronchial hyperreactivity, direct evidence for such a role is not available. In the present study it was investigated whether delayed-type hypersensitivity (DTH) to picryl chloride (PCI) in mice used as a model for cellular immunity can induce airway hyperreactivity. DTH infiltrates in the lungs of PCI-sensitized and challenged BALB/c mice occurred at 24 h after challenge, and they were maximal at 48 h. The inflammatory infiltrate resolved gradually and disappeared completely after 14 days. Whether or not the DTH-like inflammatory reaction influenced lung function parameters was tested in vivo. From these experiments it was concluded that the pulmonary resistance in mice with a DTH-like inflammation was increased. Dynamic compliance was unchanged. In PCI-sensitized and challenged...

Patients with the nucleotide excision repair (NER) disorder xeroderma pigmentosum (XP) are highly predisposed to develop sunlight-induced skin cancer, in remarkable contrast to photosensitive NER-deficient trichothiodystrophy (TTD) patients carrying mutations in the same XPD gene. XPD encodes a helicase subunit of the dually functional DNA repair/basal transcription complex TFIIH. The pleiotropic disease phenotype is hypothesized to be, in part, derived from a repair defect causing UV sensitivity and, in part, from a subtle, viable basal transcription deficiency accounting for the cutaneous, developmental, and the typical brittle hair features of TTD. To understand the relationship between deficient NER and tumor susceptibility, we used a mouse model for TTD that mimics an XPD point mutation of a TTD patient in the mouse germline. Like the fibroblasts from the patient, mouse cells exhibit a partial NER defect, evident from the reduced UV-induced DNA repair synthesis (residual repair...

Previously it was demonstrated that during delayed-type hypersensitivity reactions (DTH) to picryl chloride (PCl) in murine lungs, as a model for cellular IgE-independent immunity, tracheal hyperreactivity and increased pulmonary resistance are induced. In the present study it is demonstrated that after pretreatment with 5HT-2 antagonists, such as ketanserin and methysergide, DTH lung reactions to PCl in mice are suppressed. The increase in vascular permeability, detectable at 2 h after intranasal hapten challenge and probably necessary for the development of a classic DTH reaction, as was demonstrated in skin DTH models, as well as the classic late inflammatory component of lung DTH, is inhibited. However, in vitro tracheal hyperreactivity to the cholinergic receptor agonist carbachol and increased pulmonary resistance in vivo, both induced during the development of these inflammatory DTH lung reactions, are not affected by 5HT-2 receptor antagonist pretreatment. These results indi...

Ultraviolet (UV) B-induced morphological and functional changes in the skin of mice, rats and humans were investigated. Changes in the morphological structure of Langerhans cells (LC), the major antigen-presenting cells in the skin, using confocal laser scanning microscopy, were found in mouse and rat skin after in situ exposure to high doses of UVB radiation (FS40) (3-9 kJ/m2). Similar UVB doses failed to induce alterations in the morphological structure of human LC. Alterations in the function of epidermal cells (especially LC) were studied, using the mixed skin lymphocyte response (MSLR). In vitro UVB exposure of epidermal cells (EC), derived from the skin of the different species, revealed that low doses of UVB radiation impaired the stimulatory capacity of these cells dose-dependently; mouse epidermal cells were most UVB-susceptible, while human cells were least UVB susceptible. For suppression of the stimulatory capacity of EC after in situ UVB exposure of skin tissue, higher doses of UVB radiation than the in vitro UVB exposure were needed in all species tested. Also in this in situ set-up mouse epidermal cells were most UVB-susceptible, and human epidermal cells were least UVB-susceptible. The magnitude of differences in susceptibility for UVB-induced changes in the stimulatory capacity of EC after in situ and after in vitro exposure experiments was similar. Firstly, it may be concluded that UVB impairs the functional activity of LC at a lower dose than that which alters the morphology of these cells. Secondly, it is clear that epidermal cells, especially LC, from the skin of rodents are more susceptible to UVB than epidermal cells derived from human skin. It is important to account for these differences in susceptibility when data on the effects of UVB radiation on the immune system in rodents are extrapolated to humans.

Over the last decade, there has been a growing interest in the use of interventions that target the intestinal microbiota as a treatment approach for asthma. This study is aimed at exploring the therapeutic effects of long-term treatment with a combination of Bifidobacterium breve with non-digestible oligosaccharides on airway inflammation and remodeling. A murine ovalbumin-induced chronic asthma model was used. Pulmonary airway inflammation; mRNA expression of pattern recognition receptors, Th-specific cytokines and transcription factors in lung tissue; expression of Foxp3 in blood Th cells; in vitro T cell activation; mast cell degranulation; and airway remodeling were examined. The combination of B. breve with non-digestible oligosaccharides suppressed pulmonary airway inflammation; reduced T cell activation and mast cell degranulation; modulated expression of pattern recognition receptors, cytokines and transcription factors; and reduced airway remodeling. The treatment induced regulatory T cell responses, as shown by increased Il10 and Foxp3 transcription in lung tissue, and augmented Foxp3 protein expression in blood CD4+CD25+Foxp3+ T cells. This specific combination of beneficial bacteria with non-digestible oligosaccharides has strong anti-inflammatory properties, possibly via the induction of a regulatory T cell response, resulting in reduced airway remodeling and, therefore, may be beneficial in the treatment of chronic inflammation in allergic asthma.

To evaluate the effects of differences in host cellular immunity, we studied the dose-response relationship for infection with Salmonella enterica serovar Enteritidis (SE) in two different rat strains, skewed towards T helper 1 (Th1, Lewis rats) or T helper 2 (Th2, Brown Norway rats) immunoregulation. Rats were exposed orally to different doses of SE after overnight starvation and neutralization of gastric acid. Animals were observed for clinical signs of disease, fecal excretion and SE load in spleen and cecum, histopathology of the cecum, hematology, and cellular and humoral immune responses. Exponential dose-response models were used for binary or continuous outcomes to analyze the experimental data. Cytokine patterns, antibody isotypes, and contact hypersensitivity tests confirmed that Lewis rats are Th1 prone, whereas Brown Norway rats are Th2 prone. The probability of infection per single SE cell was approximately 100 times higher in Brown Norway rats than in Lewis rats. Cellu...

Toluene diisocyantate (TDI) is a low-molecular-weight compound that is known to cause occupational asthma in 5% to 10% of exposed workers. These patients exhibit marked airway hyperresponsiveness and granulocyte accumulation in the airways, and 10% to 20% were also determined to have TDI-specific IgE in their serum. In this study, we developed a murine model for TDI-induced asthma. After several sensitization and challenge regimens were tested, it was decided that optimal sensitization was observed after mice (BALB/c) were skin sensitized with TDI (1%) two times on two consecutive days and challenged intranasally 8 d later with TDI (1%). Sensitized mice exhibited tracheal hyperreactivity to carbachol 24 h after challenge (69% increase in maximal contractile response). In contrast, no differences between the control and TDI-treated groups was observed 2 and 48 h after challenge with 1% TDI. There appeared to be no elevation in TDI-specific IgE antibodies in the serum at all time points measured. In addition, no influx of leukocytes could be detected histologically in the trachea and lung tissue or airway lumen 2, 24, and 48 h after the challenge. Surprisingly, the tracheal hyperreactivity was associated with a marked increase in myeloperoxidase but not eosinophil peroxidase activity in the lung tissue and in the cells of the bronchoalveolar lavage fluid at 24 h after the challenge. To investigate the role of lymphocytes in the induction of tracheal hyperreactivity, mice were passively sensitized by intravenous injection of lymphoid cells from TDI-sensitized donor mice. Similar to active sensitization, adoptive transfer of lymphocytes from sensitized donors resulted in tracheal hyperreactivity 24 h after challenge of the recipients. In conclusion, these data show that TDI is capable of inducing lymphocyte-dependent but IgE-independent tracheal hyperreactivity in the mouse that is not associated with cellular infiltration in the airways. This model can be used to further investigate the possible mechanisms involved in the development of occupational asthma induced by TDl.