Search results for "allergens"
showing 10 items of 172 documents
Comparison of allergen-stimulated dendritic cells from atopic and nonatopic donors dissecting their effect on autologous naive and memory T helper ce…
2000
Abstract Background: Because of their production of IL-12, mature dendritic cells (DC) are potent inducers of T H 1 responses. However, recent reports have demonstrated that DCs can also induce T H 2 differentiation. Objective: In the current study we investigated which immune response is induced by DCs in naive CD45RA + or memory CD45R0 + CD4 + T cells from atopic individuals (patients with grass pollen, birch pollen, or house dust mite allergy) compared with nonatopic control subjects. Methods: Immature DCs, generated from peripheral blood monocytes from atopic and nonatopic donors, were pulsed with the respective allergen and fully matured. Then the mature DCs were cocultured in vitro wi…
Regulatory activity of human CD4 CD25 T cells depends on allergen concentration, type of allergen and atopy status of the donor.
2005
Regulatory CD4+ CD25+ FoxP3-positive T cells (Treg) are functional in most atopic patients with allergic rhinitis and are able to inhibit T helper type 1 (Th1) and Th2 cytokine production of CD4+ CD25- T cells. This study was designed to analyse the following additional aspects: influence of allergen concentration, influence of the type of allergen, and influence of the atopy status of the donor on the strength of the regulatory activity. CD4+ CD25- T cells from healthy non-atopic controls or from grass-pollen-allergic or wasp-venom-allergic donors were stimulated alone or in the presence of Treg with autologous mature monocyte-derived dendritic cells which were pulsed with different concen…
Inhibition of human allergic T-cell responses by IL-10–treated dendritic cells: Differences from hydrocortisone-treated dendritic cells
2001
Abstract Background: Dendritic cells (DCs) are able to induce human allergic T H 1 responses as well as T H 2 responses. Objective: In this study, we examined the effect of antiinflammatory agents such as IL-10 and hydrocortisone (HC) on the accessory function of DCs and the resulting T-cell response, especially that of T H 2 cells. Methods: Naive and memory CD4 + T cells from atopic donors were stimulated with autologous allergen-pulsed DCs generated from CD14 + monocytes by culture with GM-CSF/IL-4 and fully matured with IL-1β, TNF-α, and PGE 2 in the presence or absence of IL-10 or HC. Results: IL-10–treated DCs and, to a lesser extent, HC-treated DCs showed a decreased expression of MHC…
Modification of the human allergic immune response by allergen-DNA-transfected dendritic cells in vitro.
2004
Abstract Background Atopic-allergic diseases are characterized by T H 2-dominated immune responses, resulting in IgE production. DNA-based immunotherapies have been shown to shift the immune response toward a T H 1-type response in animal models. Objective The aim of the study was to analyze whether dendritic cells (DCs) transfected with allergen-DNA conjugates are able to stimulate human autologous CD4 + T cells, CD8 + T cells, or both from atopic individuals to produce T H 1 cytokines instead of T H 2 cytokines. Methods For this purpose, human mature DCs from atopic donors were transfected with an adenovirus encoding the allergen Phl p 1. Autologous CD4 + and CD8 + T cells were stimulated…
Epicutaneous and Oral Low-Zone Tolerance Protects from Colitis in Mice
2016
Tolerance to environmental antigens that encounter the organism at interfaces like skin or gut prevents deleterious systemic immune responses. The aim of this study was to analyze whether and how low doses of haptens, by entry through the skin or gastrointestinal tract, affect the outcome of the predominantly Th1/Th17-mediated 2,4,6-trinitro-benzenesulfonic acid-induced colitis, which mimics an autoimmune bowl disease in man. Epicutaneous and oral applications of low doses of the allergen resulted in the induction of low-zone tolerance (LZT) and protected from colitis development, demonstrated by a significantly reduced inflammatory response of the gut in vivo. In line with this observation…
Induction of regulatory T cells by leflunomide in a murine model of contact allergen sensitivity.
2006
Allergic contact dermatitis and contact hypersensitivity (CHS) are characterized by allergen-specific activation of CD8 + and CD4 + T cells and the production of cytokines resulting in an inflammatory response and tissue damage. We show here that the immunosuppressive compound leflunomide ( N -[4-trifluoro-methylphenyl]-5-methylisoxazol-4 carboxamide, HWA 486) (LF) inhibited the contact allergic response induced in mice by epicutaneous application of the haptens dinitrofluorobenzene (DNFB) and oxazolone. The extent of ear swelling remained significantly reduced following repeated challenge with DNFB for up to 18 weeks. LF and DNFB had to be applied simultaneously for inhibition to occur. Th…
Activated glycoprotein A repetitions predominant (GARP)-expressing regulatory T cells inhibit allergen-induced intestinal inflammation in humanized m…
2015
Background Recently, we developed a humanized mouse model of allergen-induced IgE-dependent gut inflammation in PBMC-engrafted immunodeficient mice. Objective In the present study, we wanted to investigate the role of regulatory T (Treg) cells and their activation status in this model. Methods Nonobese diabetic-severe combined immunodeficiency-γc −/− mice were injected intraperitoneally with human PBMCs from allergic donors together with the respective allergen or NaCl as control in the presence or absence of different concentrations of CD4 + CD25 + Treg cells of the same donor. After an additional allergen boost 1 week later, mice were challenged with the allergen rectally on day 21 and gu…
IL-2 receptor beta-chain signaling controls immunosuppressive CD4+ T cells in the draining lymph nodes and lung during allergic airway inflammation i…
2008
Abstract IL-2 influences both survival and differentiation of CD4+ T effector and regulatory T cells. We studied the effect of i.n. administration of Abs against the α- and the β-chains of the IL-2R in a murine model of allergic asthma. Blockade of the β- but not the α-chain of the IL-2R after allergen challenge led to a significant reduction of airway hyperresponsiveness. Although both treatments led to reduction of lung inflammation, IL-2 signaling, STAT-5 phosphorylation, and Th2-type cytokine production (IL-4 and IL-5) by lung T cells, IL-13 production and CD4+ T cell survival were solely inhibited by the blockade of the IL-2R β-chain. Moreover, local blockade of the common IL-2R/IL-15R…
Influenza A virus infection inhibits the efficient recruitment of Th2 cells into the airways and the development of airway eosinophilia.
2003
Abstract Most infections with respiratory viruses induce Th1 responses characterized by the generation of Th1 and CD8+ T cells secreting IFN-γ, which in turn have been shown to inhibit the development of Th2 cells. Therefore, it could be expected that respiratory viral infections mediate protection against asthma. However, the opposite seems to be true, because viral infections are often associated with the exacerbation of asthma. For this reason, we investigated what effect an influenza A (flu) virus infection has on the development of asthma. We found that flu infection 1, 3, 6, or 9 wk before allergen airway challenge resulted in a strong suppression of allergen-induced airway eosinophil…
Cypress pollen: An unexpected major sensitizing agent in different regions of Italy
2014
In this multicenter survey, we assessed the impact of sensitization to cypress in atopic patients in Italy and determined whether cypress pollen concentration changed over time.Allergists were required to collect the results of 100-200 consecutive skin prick tests (SPTs) performed during 2012. Seasonal symptoms were also recorded, as were airborne cypress pollen concentrations (data from the Italian Aerobiology Association) in 1998-2000 and 2010-2012.We examined 2258 atopic outpatients (56% females; age, 2-84 years) sensitized to at least 1 of the aeroallergens tested (Dermatophagoides species, grass, pellitory, olive, cypress, birch, Alternaria tenuis, and dog and cat dander). We found tha…