首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 11 毫秒
1.
  相似文献   

2.
Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by IgE-mediated reactions to bites of insects of the genus Culicoides. IBH does not occur in Iceland due to the absence of Culicoides. However, Icelandic horses exported to mainland Europe as adults (1st generation) have a > or =50% incidence of developing IBH. In contrast, their progeny (2nd generation) has a <10% incidence of IBH. Here we show that peripheral blood mononuclear cells (PBMC) from Icelandic horses born in mainland Europe and belonging either to the IBH or healthy subgroup produce less interleukin (IL)-4 after polyclonal or allergen-specific stimulation when compared with counterparts from horses born in Iceland. We examined a role of IL-10 and transforming growth factor (TGF)-beta1 in down-regulation of IL-4 in healthy 2nd generation Icelandic horses. Supernatants of PBMC from 2nd generation healthy horses down-regulated the proportion of IL-4-producing cells and IL-4 production in stimulated cultures of PBMC from 1st generation IBH. This inhibition was mimicked by a combination of IL-10 and TGF-beta1 but not by the single cytokines. Cultures of stimulated PBMC of healthy 2nd generation horses produced a low level of IL-4, but IL-4 production was increased by anti-equine IL-10 and anti-human TGF-beta1. This shows for the first time that in horses, IL-10 and TGF-beta1 combined regulate IL-4 production in vitro. It is suggested that in this naturally occurring IgE-mediated allergy, IL-10 and TGF-beta1 have a role in the down-regulation of IL-4-induced allergen-specific Th2 cells, thereby reducing the incidence of IBH.  相似文献   

3.
  相似文献   

4.
REASONS FOR PERFORMING STUDY: Insect bite hypersensitivity (IBH) is an IgE-mediated allergic dermatitis caused by bites of Culicoides and Simulium species, and improved means of diagnosis are required. OBJECTIVES: The cellular antigen simulation test (CAST) with C. nubeculosus and S. vittatum extracts was assessed in a population of IBH-affected and healthy horses. Variations in test results over a one year period and possible cross-reactivity between different insect extracts was studied. METHODS: A total of 314 mature horses were studied using the CAST. Influence of severity of clinical signs, gender and age were evaluated, and 32 horses were tested repeatedly over one year. The kappa reliability test was used to assess agreement of the test results with different insect extracts. RESULTS: Horses with IBH had significantly higher sLT release than controls with C. nubeculosus and S. vittatum. The highest diagnostic sensitivity and specificity levels were attained when using adult C. nubeculosus extracts with the CAST (78% and 97%, respectively), suggesting that most horses with IBH are sensitised against Culicoides allergens. A proportion of IBH-affected horses was found to be sensitised to allergens of Simulium spp. in addition to those of C. nubeculosus. The CAST with C. nubeculosus had positive and negative predictive values > or = 80% for a true prevalence of IBH of 12-52%. In the follow-up study, the proportion of IBH-affected horses with a positive test result ranged from 90% in November to 68% in March. Severity of clinical signs or age did not influence test results significantly. However, IBH-affected males achieved significantly more positive test results than IBH-affected females. CONCLUSIONS: The CAST with adult C. nubeculosus has high specificity and good sensitivity for diagnosis of IBH. Horses with IBH are mainly sensitised to Culicoides allergens, and some horses are additionally also sensitised to allergens in Simulium spp. POTENTIAL RELEVANCE: The CAST is likely to be a useful test for diagnosis of IBH, even allowing the identification of IBH-affected but asymptomatic horses. This test may also help in further characterisation of allergens involved in this condition.  相似文献   

5.
Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by IgE-mediated reactions to bites of Culicoides and sometimes Simulium spp. The allergens causing IBH are probably salivary gland proteins from these insects, but they have not yet been identified. The aim of our study was to identify the number and molecular weight of salivary gland extract (SGE) proteins derived from Culicoides nubeculosus which are able to bind IgE antibodies (ab) from the sera of IBH-affected horses. Additionally, we sought to investigate the IgG subclass (IgGa, IgGb and IgGT) reactivity to these proteins. Individual IgE and IgG subclass responses to proteins of C. nubeculosus SGE were evaluated by immunoblot in 42 IBH-affected and 26 healthy horses belonging to different groups (Icelandic horses born in Iceland, Icelandic horses and horses from different breeds born in mainland Europe). Additionally, the specific antibody response was studied before exposure to bites of Culicoides spp. and over a period of 3 years in a cohort of 10 Icelandic horses born in Iceland and imported to Switzerland. Ten IgE-binding protein bands with approximate molecular weights of 75, 66, 52, 48, 47, 32, 22/21, 19, 15, 13/12 kDa were found in the SGE. Five of these bands bound IgE from 50% or more of the horse sera. Thirty-nine of the 42 IBH-affected horses but only 2 of the 26 healthy horses showed IgE-binding to the SGE (p<0.000001). Similarly, more IBH-affected than healthy horses had IgGa ab binding to the Culicoides SGE (19/22 and 9/22, respectively, p<0.01). Sera of IBH-affected horses contained IgE, IgGa and IgGT but not IgGb ab against significantly more protein bands than the sera of the healthy horses. The cohort of 10 Icelandic horses confirmed these results and showed that Culicoides SGE specific IgE correlates with onset of IBH. IBH-affected horses that were born in Iceland had IgGa and IgGT ab (p< or =0.01) as well as IgE ab (p=0.06) against a significantly higher number of SGE proteins than IBH-affected horses born in mainland Europe. The present study shows that Culicoides SGE contains at least 10 potential allergens for IBH and that IBH-affected horses show a large variety of IgE-binding patterns in immunoblots. These findings are important for the future development of a specific immunotherapy with recombinant salivary gland allergens.  相似文献   

6.
Several distinct T lymphocyte subpopulations with immunoregulatory activity have been described in a number of mammalian species. This study performed a phenotypic analysis of cells expressing regulatory T cell (Treg) markers in the peripheral blood of a cohort of 18 horses aged 6 months to 23 years, using antibodies to both intracellular and cell surface markers, including Forkhead box P3 (FOXP3), CD4, CD8, CD25, interferon gamma (IFNγ) and interleukin 10 (IL-10). In peripheral blood, a mean of 2.2 ± 0.2% CD4+ and 0.5 ± 0.1% CD8+ lymphocytes expressed FOXP3. The mean percentage of CD4+FOXP3+ cells was found to be significantly decreased in horses 15 years and older (1.5%) as compared to horses 6 years and younger (2.7%), but did not differ between females and males and ponies and horses. Activation of peripheral blood mononuclear cells by pokeweed mitogen resulted in induction of CD25 and FOXP3 expression by CD4+ cells, with peak expression noted after 48 and 72 h in culture respectively. Activated CD4+FOXP3+ cells expressed IFNγ (35% of FOXP3+ cells) or IL-10 (9% FOXP3+ cells). Cell sorting was performed to determine FOXP3 expression by CD4(+)CD25(-), CD4(+)CD25(dim) and CD4(+)CD25(high) subpopulations. Immediately following sorting, the percentage of CD4+FOXP3+ cells was higher within the CD4(+)CD25(high) population (22.7-26.3%) compared with the CD4(+)CD25(dim) (17% cells) but was similar within the CD4(+)CD25(dim) and CD4(+)CD25(high) cells after resting in IL-2 (9-14%). Fewer than 2% of cells in the CD4(+)CD25(-) population expressed FOXP3. These results demonstrate heterogeneity in equine lymphocyte subsets that express molecules associated with regulatory T cells. CD4+FOXP3+ cells are likely to represent natural Tregs, with CD4+FOXP3+IL-10+ cells representing either activated natural Tregs or inducible Tregs, and CD4+FOXP3+IFNγ+ cells likely to represent activated Th1 cells.  相似文献   

7.
  相似文献   

8.
  相似文献   

9.
Insect bite dermal hypersensitivity (IBH) is an allergic dermatitis of horses caused by bites of Culicoides spp. and sometimes Simulium spp. The aim of the investigation presented here was to identify allergens causing IBH. A cDNA library expressing recombinant Culicoides nubeculosus proteins was screened using affinity-purified serum from an IBH-affected horse. Screening of the library resulted in identification of one immunoreactive clone. The sequence of the cDNA insert was determined and revealed a 600 bp insert with an open reading frame coding for a 78 amino acid long protein, called rCul n 1. Analysis of the deduced amino acid sequence revealed an identity of 67-78% to the C-terminal part of the 318 amino acid long ribosomal P0 protein from other Diptera. Furthermore, the 38 C-terminal amino acids displayed an identity of 57% with the C-terminal part of the acidic ribosomal protein P2 from Aspergillus fumigatus. The cDNA insert was subcloned and expressed as a [His]6-tagged protein in Escherichia coli and purified using Ni2(+)-chelate affinity chromatography. The 10kDa recombinant Cul n 1 protein bound the affinity-purified antibody fraction used for screening the expression library. Determination of IgE and IgG levels against rCul n 1 by ELISA in sera from 19 IBH-affected and 18 Swiss control horses and in sera from eight control horses living in Iceland showed no significant differences between the three groups of horses (median IgE levels = 60, 49 and 44 relative ELISA units, respectively). rCul n 1 did not induce sulfidoleukotriene (sLT) release from peripheral blood leukocytes of IBH-affected horses (N = 5), although sLT release was induced with the Culicoides whole body extract.  相似文献   

10.
Thymic CD4(+)CD25(+) cells from ducks were characterized for mammalian T regulatory cells' suppressive and cytokine production properties. The cross reactivity of anti-chicken CD25 monoclonal antibody with duck CD25 was confirmed by evaluating Concanavalin-A-stimulated CD25 upregulation in splenocytes. CD4(+)CD25(+) cells were detectable in the thymus, spleen, cecal tonsil, and lung (airsacs), but not in the bursa. Duck CD4(+)CD25(+) cells had approximately nine-fold higher IL-10 mRNA, 12-fold higher TGF-β, 16-fold higher CTLA-4, and nine-fold higher LAG-3 mRNA amounts than thymic CD4(+)CD25(-) cells. Thymic CD4(+)CD25(+) cells had no detectable levels of IL-2 mRNA. Duck CD4(+)CD25(+) cells had a three-fold higher IL-10 mRNA amount than chicken CD4(+)CD25(+) cells. Duck CD4(+)CD25(+) cells were anergic in vitro. Duck CD4(+)CD25(+) cells suppressed naive cell proliferation at effector: responder cell ratios above 0.5:1 in both contact-dependent and -independent pathways. It could be concluded that thymic CD4(+)CD25(+) cells in ducks are most likely the counterpart of mammalian T regulatory cells.  相似文献   

11.
HIV-induced AIDS may be mediated by the activation of immunosuppressive CD4+CD25+ T regulatory cells (Treg cells). Treg cells have been shown to regulate CD4+ and CD8+ immune responses to HIV and FIV antigens in vitro. We tested the hypothesis that Treg cells become infected and activated during the acute infection with FIV leading to the suppression of CD4+ T helper cell responses. Cats were experimentally infected with FIV-NCSU1 and blood and lymph node cells were collected at weekly intervals following inoculation. Real-time RT-PCR was used to determine plasma viremia and the relative expression of FIV, FoxP3, TGF-beta, and GAPDH mRNA copies in CD4+CD25+ and CD4+CD25- T cell subsets. Flow cytometry was used to assess the absolute numbers of each cell type and the expression of surface TGF-beta and intracellular FoxP3 in CD4+CD25+ and CD4+CD25- T cells at each time-point. Treg suppression of IL-2 production in CD4+ T helper cells was assessed by ELISPOT assays. Our results showed that peak viremia occurred at 2 weeks post infection and correlated with maximal infectivity in CD4+CD25+ T cell populations. FIV-gag-mRNA levels were higher in CD4+CD25+ T cells than CD4+CD25- T cells throughout the acute phase of infection. Induction of FoxP3 and TGF-beta indicated activation of Treg cells during the acute stage infection, which was confirmed by Treg cell suppression of IL-2 production by CD4+ Th cells in an ELISPOT assay. Our findings support the hypothesis that early activation of Treg immunosuppressor function may limit an effective anti-FIV response, contributing to the establishment of chronic infection and the immunodeficiency caused by this virus.  相似文献   

12.
Salivary gland proteins of Culicoides spp. have been suggested to be among the main allergens inducing IgE-mediated insect bite hypersensitivity (IBH), an allergic dermatitis of the horse. The aim of our study was to identify, produce and characterize IgE-binding salivary gland proteins of Culicoides nubeculosus relevant for IBH by phage surface display technology. A cDNA library constructed with mRNA derived from C. nubeculosus salivary glands was displayed on the surface of filamentous phage M13 and enriched for clones binding serum IgE of IBH-affected horses. Ten cDNA inserts encoding putative salivary gland allergens were isolated and termed Cul n 2 to Cul n 11. However, nine cDNA sequences coded for truncated proteins as determined by database searches. The cDNA sequences were amplified by PCR, subcloned into high level expression vectors and expressed as hexahistidine-tagged fusion proteins in Escherichia coli. Preliminary ELISA results obtained with these fusions confirmed the specific binding to serum IgE of affected horses. Therefore, the putative complete open reading frames derived from BLAST analyses were isolated by RACE-PCR and subcloned into expression vectors. The full length proteins expressed in Escherichia coli showed molecular masses in the range of 15.5-68.7 kDa in SDS-PAGE in good agreement with the masses calculated from the predicted protein sequences. Western blot analyses of all recombinant allergens with a serum pool of IBH-affected horses showed their ability to specifically bind serum IgE of sensitized horses, and ELISA determinations yielded individual horse recognition patterns with a frequency of sensitization ranging from 13 to 57%, depending on the allergen tested. The in vivo relevance of eight of the recombinant allergens was demonstrated in intradermal skin testing. For the two characterized allergens Cul n 6 and Cul n 11, sensitized horses were not available for intradermal tests. Control horses without clinical signs of IBH did not develop any relevant immediate hypersensitivity reactions to the recombinant allergens. The major contribution of this study was to provide a repertoire of recombinant salivary gland allergens repertoire from C. nubeculosus potentially involved in the pathogenesis of IBH as a starting basis for the development of a component-resolved serologic diagnosis of IBH and, perhaps, for the development of single horse tailored specific immunotherapy depending on their component-resolved sensitization patterns.  相似文献   

13.
Interleukin-3 is a growth and differentiation factor for various hematopoietic cells. IL-3 also enhances stimulus-dependent release of mediators and cytokine production by mature basophils. Function of IL-3 has not been studied in horses because of lack of horse-specific reagents. Our aim was to produce recombinant equine IL-3 and test its effect on sulfidoleukotriene and cytokine production by equine peripheral blood leukocytes (PBL).Equine IL-3 was cloned, expressed in E. coli and purified. PBL of 19 healthy and 20 insect bite hypersensitivity (IBH)-affected horses were stimulated with Culicoides nubeculosus extract with or without IL-3. Sulfidoleukotriene (sLT) production was measured in supernatants by ELISA and mRNA expression of IL-4, IL-13 and thymic stromal lymphopoietin (TSLP) assessed in cell lysate by quantitative real-time PCR.Recombinant equine IL-3 (req-IL-3) had a dose dependent effect on sLT production by stimulated equine PBL and significantly increased IL-4, IL-13 and TSLP expression compared to non-primed cells.IL-3 priming significantly increased Culicoides-induced sLT production in IBH-affected but not in non-affected horses and was particularly effective in young IBH-affected horses (≤3 years).A functionally active recombinant equine IL-3 has been produced which will be useful for future immunological studies in horses. It will also allow improving the sensitivity of cellular in vitro tests for allergy diagnosis in horses.  相似文献   

14.
In chickens, thymic CD4(+)CD25(+) cells are characterized as regulatory T cells. The objectives of this experiment were to study the effects of an in vivo lipopolysaccharide (LPS) injection on the percentage of CD4(+)CD25(+) cells in peripheral organs and the suppressive properties of splenic CD4(+)CD25(+) cells in chickens. Chickens were injected with LPS and CD4(+)CD25(+) cells were analyzed at 1, 2, 3, 5, and 10 d post LPS injection. The LPS injection increased CD4(+)CD25(+) cell percentage approximately 5-fold in the blood at 1 d post LPS injection (P < 0.001), 3-fold in the thymus at 3 d post LPS injection (P = 0.001), and 2.5-fold in the spleen at 2 d post LPS injection (P = 0.001) compared with the no-LPS-injected group. The LPS injection did not alter the CD4(+)CD25(+) cell percentage in the cecal tonsil (P = 0.162), lung (P = 0.098), or bone marrow (P = 0.071) at any time point measured. At 2 d post LPS injection, splenic CD4(+)CD25(+) cells lost their suppressive ability (P < 0.001). At 5 d post LPS injection, splenic CD4(+)CD25(+) cells not only regained their suppressive ability, but also became supersuppressive (P < 0.001). Splenic CD4(+)CD25(+) cells at 5 d post LPS injection produced 5.5-fold more (P = 0.005) IL-10 mRNA than splenic CD4(+)CD25(+) cells at 0 and 2 d post LPS injection. In conclusion, chicken regulatory T cells are differentially activated to facilitate immune response during the early stage of inflammation and to facilitate immune suppression at a later stage of inflammation.  相似文献   

15.
Increases in numbers or activities of regulatory T lymphocytes (Tregs) have been linked to the establishments of several persistent infections. It has been previously shown that porcine reproductive and respiratory syndrome virus (PRRSV) can negatively modulate the host immune responses, resulting in persistent infection and secondary immunodeficiency. Recently, the existence of porcine CD4+CD25+ Tregs has been demonstrated. We investigated the effect of PRRSV on the CD4+CD25+ Tregs. The CD4+CD25+Foxp3+ T lymphocytes in the peripheral blood mononuclear cells (PBMCs) were identified, using the anti-human anti-Foxp3 monoclonal antibody. In vitro culture of porcine PBMC in the presence of PRRSV, but not classical swine fever virus, significantly increased the numbers of Foxp3+ lymphocytes, particularly in the CD4+CD25high subpopulation. The time-course study revealed that PRRSV significantly increased the numbers of viral-specific CD4+CD25highFoxp3+ subpopulation in the culture starting from 12 h through the end of the observation period. Consistent to the results obtained by flow cytometry, enhanced Foxp3 gene expression was observed in the PBMC cultured with PRRSV in a time-course manner. The presence of monocyte-derived DC in the co-culture significantly enhanced the induction of CD4+CD25+ Foxp3+ T lymphocytes. The PRRSV-induced CD4+CD25high T lymphocytes exhibited suppressive activity when co-cultured with PHA-activated, autologous peripheral blood leukocytes, indicating the suppressive activity of the PRRSV-specific Tregs. In addition, PRRSV exposure significantly increased the numbers of PRRSV-specific CD4+CD25+Foxp3+ subpopulation in the PBMC of infected pigs at 10 days post-infection. In summary, the results indicated that PRRSV could increase the numbers of viral-specific, inducible regulatory T lymphocytes in the porcine PBMC, both in vitro and in vivo. The findings suggested the novel immunomodulatory mechanism induced by PRRSV.  相似文献   

16.
Interleukin-10 (IL-10) terminates inflammatory immune responses and inhibits activation and effector functions of T-cells, monocytes, macrophages and dendritic cells. IL-10 has also been found to be a key cytokine expressed by subpopulations of regulatory T-cells. In this report, we describe the generation and characterization of three monoclonal antibodies (mAbs) to equine IL-10. The antibodies were found to be specific for equine IL-10 using different recombinant equine cytokine/IgG fusion proteins. Two of the anti-equine IL-10 mAbs were selected for ELISA to detect secreted IL-10 in supernatants of mitogen stimulated equine peripheral blood mononuclear cells (PBMC). The sensitivity of the ELISA for detecting secreted IL-10 was found to be around 200pg/ml. The production of intracellular IL-10 was measured in equine PBMC by flow cytometry. PBMC were stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin in the presence of the secretion blocker Brefeldin A. All three anti-IL-10 mAbs detected a positive population in PMA stimulated lymphocytes which was absent in the medium controls. Around 80% of the IL-10(+) cells were CD4(+). Another 15% were CD8(+) cells. Double staining with IL-4 or interferon-gamma (IFN-gamma) indicated that PMA and ionomycin stimulation induced 80% IL-10(+)/IFN-gamma(+) lymphocytes, while only 5% IL-10(+)/IL-4(+) cells were observed. By calculation, at least 60% of the IL-10(+)/IFN-gamma(+) cells were CD4(+) lymphocytes. This expression profile corresponds to the recently described T regulatory 1 (T(R)1) cell phenotype. In summary, the new mAbs to equine IL-10 detected native equine IL-10 by ELISA and flow cytometry and can be used for further characterization of this important regulatory cytokine in horses.  相似文献   

17.
  相似文献   

18.
Insect bite hypersensitivity (IBH) is an allergic dermatitis of the horse caused by bites of insects of the genus Culicoides and is currently the best characterized allergic disease of horses. This article reviews knowledge of the immunopathogenesis of IBH, with a particular focus on the causative allergens. Whereas so far hardly any research has been done on the role of antigen presenting cells in the pathogenesis of IBH, recent studies suggest that IBH is characterized by an imbalance between a T helper 2 (Th2) and regulatory T cell (T(reg)) immune response, as shown both locally in the skin and with stimulated peripheral blood mononuclear cells. Various studies have shown IBH to be associated with IgE-mediated reactions against salivary antigens from Culicoides spp. However, until recently, the causative allergens had not been characterized at the molecular level. A major advance has now been made, as 11 Culicoides salivary gland proteins have been identified as relevant allergens for IBH. Currently, there is no satisfactory treatment of IBH. Characterization of the main allergens for IBH and understanding what mechanisms induce a healthy or allergic immune response towards these allergens may help to develop new treatment strategies, such as immunotherapy.  相似文献   

19.
In dogs a CD4(+)CD8(+) double positive T cell subpopulation exists that has not been phenotypically defined yet. We demonstrate that canine CD4(+)CD8(+) T cells are mature CD1a(-) and TCRαβ(+) T cells. To analyse the activation potential of CD4(+)CD8(+) T cells, PBMC from dogs vaccinated against canine distemper virus (CDV) were re-stimulated with CDV. Upon antigen-specific stimulation, the CD4(+)CD8(+) T cell fraction increases and consists nearly exclusively of proliferated cells. Similarly, other features of activated effector/memory T cells such as up-regulation of CD25 and MHC-II as well as down-regulation of CD62L (L-selectin) were observed in CD4(+)CD8(+) T cells after stimulation. Canine CD4(+)CD8(+) T cells are less abundant, but more heterogeneous than porcine ones, comprising a small proportion expressing the β chain of CD8 in addition to the CD8α chain, like human CD4(+)CD8(+) T cells. In summary, this analysis provides the basis for functional characterisation of the in vivo relevance of CD4(+)CD8(+) T cells in T-cell mediated immunity.  相似文献   

20.
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号