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1.
Marti E Urwyler A Neuenschwander M Eicher R Meier D de Weck AL Gerber H Lazary S Dahinden CA 《Veterinary immunology and immunopathology》1999,71(3-4):307-320
Sulfidoleukotrienes (sLT) generated in vitro after incubation of equine peripheral blood leukocytes (PBL) with different inducing agents were determined in 18 healthy and 16 insect bite dermal hypersensitivity (IDH)-affected horses. PBL from these 32 horses were stimulated with Concanavalin A, Parascaris equorum, Culicoides nubeculosus and Simulium extracts, and with a six-Grass mix. The cells of all but four horses generated sLT after incubation with Concanavalin A; these four horses did also not produce sLT with the other inducing agents. Of the 28 remaining horses (12 affected with IDH and 16 healthy), all but three generated sLT with the P. equorum extract. The six-Grass mix did not induce sLT production in any of the tested horses. sLT generation with Concanavalin A and Parascaris was statistically not different between IDH-affected and healthy horses. PBL of the diseased horses, however, produced significantly more sLT with the Culicoides (p < 0.01) and Simulium (p < 0.05) extracts than those of the healthy animals. Additionally, sLT generation with the Culicoides extract was measured at different times of the year in one IDH-affected animal and remained high even in winter, when the horse was asymptomatic. sLT and histamine release were determined in 10 horses in parallel. Positive correlations of 0.81 and 0.82 for Concanavalin A and Parascaris (p < 0.01 and p < 0.05, respectively), and of 0.95 and 0.94 for Culicoides and Simulium (p < 0.01) were found between sLT and histamine release. These results indicate that, alike in humans, sLT are released in vitro from equine basophils along with histamine in response to various stimuli and that immediate type hypersensitivity reactions to Culicoides and Simulium are often involved in the pathogenesis of IDH. Thus, sLT generation from equine basophils offers an in vitro diagnostic tool for IDH even in sensitised but asymptomatic horses. 相似文献
2.
van der Rijt R van den Boom R Jongema Y van Oldruitenborgh-Oosterbaan MM 《Veterinary journal (London, England : 1997)》2008,178(1):91-97
The aims of this study were to determine (1) which species of Culicoides is most commonly attracted to horses, (2) whether horses suffering insect hypersensitivity attract more Culicoides spp. than unaffected horses, and (3) the times when Culicoides spp. are most active. Horses affected by insect hypersensitivity and unaffected horses were placed inside mosquito netting tents for 30 min at different times of the day. All Culicoides spp. trapped inside the tents were collected and identified. C. obsoletus was the most common species found, followed by C. pulicaris. Healthy horses attracted slightly more midges than horses that were affected with insect hypersensitivity. All of the Culicoides species were most active at sunset, less so at sunrise and very few or no midges were trapped in the afternoon or at night. 相似文献
3.
Baselgia S Doherr MG Mellor P Torsteinsdottir S Jermann T Zurbriggen A Jungi T Marti E 《Equine veterinary journal》2006,38(1):40-46
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
4.
We postulated that all horses exposed to the bites of Culcoides (midges) would have an antibody response to the antigen secreted in Culcoides saliva, but that IgE antibody would be restricted to allergic individuals. Using immunohistology on sections of fixed Culicoides, we have demonstrated the presence of antibodies in horse serum which recognise Culicoides salivary glands. Antibodies were detected in the serum of horses with insect dermal hypersensitivity and in the serum of normal horses exposed to Culicoides bites. In contrast, no antibodies were detected in serum from native Icelandic ponies which had not been exposed to Culicoides. Anti-salivary gland IgG antibodies were detected in serum from both allergic and healthy horses exposed to Culicoides. IgE antibodies were only detected in horses with signs of insect dermal hypersensitivity, they were not found in serum of healthy controls nor in the serum of horses with a history of hypersensitivity but in remission at the time of sampling. Using western blotting we confirmed the presence of antibodies to Culicoides antigens and demonstrated that individual horses react to different numbers of antigens. This paper demonstrates the ability of serum from allergic horses to detect Culcoides antigens and will enable further studies to isolate and characterise the allergens. 相似文献
5.
de Raat IJ van den Boom R van Poppel M van Oldruitenborgh-Oosterbaan MM 《Tijdschrift voor diergeneeskunde》2008,133(20):838-842
Insect bite hypersensitivity (IBH) in horses is most likely caused by Culicoides species, although other insects may also play a role. Until now no effective cure has been found for this condition, although numerous therapeutic and preventive measures have been used to control insect hypersensitivity. One such method is to apply a topical insecticide to horses. In this study, the effect of a topical insecticide containing permethrin (3.6%) was examined in seven pairs of horses. The horses were placed inside a tent trap to collect Culicoides spp. and other insects attracted to the horses on two subsequent evenings. On the first evening, both horses were untreated. After the end of this session, one horse of each pair was treated with the pour-on insecticide; treated horses were kept separate from untreated horses. The next evening the pairs of horses were again placed inside the tent trap and insects were collected. Similar percentages of Culicoides were trapped as in earlier studies (C. obsoletus 95.34% and C. pulicaris 4.54%), with healthy horses attracting more Culicoides than horses affected by IBH. The number of Culicoides, the percentage of blood-fed Culicoides obsoletus, and the total number of insects attracted to horses 24 hours after treatment with permethrin were reduced but the reduction was not statistically significant. No negative side effects of permethrin administration were observed. 相似文献
6.
Wilson AD Heesom KJ Mawby WJ Mellor PS Russell CL 《Veterinary immunology and immunopathology》2008,122(1-2):94-103
IgE-mediated type 1 hypersensitivity reactions to the bites of insects are a common cause of skin disease in horses. Insect bite hypersensitivity (IBH) is most frequently associated with bites of Culicoides spp. and occurs in all parts of the world where horses and Culicoides coexist. The main allergens that cause IBH are probably some of the abundant proteins in the saliva of Culicoides associated with blood feeding. Western blots of Culicoides proteins separated by 1D gel-electrophoresis detected strong IgE responses in all horses with IBH to antigens in protein extracts from wild caught Culicoides, but only weak responses to salivary antigens from captive bred C. nubeculosus which may reflect important differences among allergens from different species of Culicoides or differences between thorax and salivary gland antigens. 2D electrophoresis and mass spectrometry were used to identify several of the abundant proteins in the saliva of C. nubeculosus. These included maltase, members of the D7 family, and several small, basic proteins associated with blood feeding. The most frequently detected IgE-binding proteins were in a group of proteins with pI>8.5 and mass 40-50kDa. Mass spectrometry identified two of these allergenic proteins as similar to hyaluronidase and a heavily glycosylated protein of unknown function that have previously been identified in salivary glands of C. sonorensis. 相似文献
7.
H Ungar-Waron Y Braverman A Gluckman Z Trainin 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1990,37(1):64-72
Summer seasonal recurrent dermatitis (SSRD) or "sweet itch" is a seasonally occurring allergic dermatitis of horses provoked by biting midges. The allergic skin reactions have been attributed to allergens present in various Culicoides species. C. imicola is the suspected etiological agent of SSRD in Israel. Whole body extracts of this midge induced hypersensitivity reactions upon injection into susceptible horses and in this study attempts were made to define components of C. imicola which have immunogenic and allergenic properties. Immunogenic potency was evaluated by raising antisera to whole body extracts of C. imicola in rabbits and examining their reactivity towards fractionated extracts. Allergenic potency was examined by reacting fractionated extracts with horse sera. Humoral reactivity of susceptible and non susceptible horses was assayed by specific IgE and IgG ELISAs. Although there are many antigenic components in whole body extracts of C.imicola capable of eliciting an immune response, no conclusive evidence was obtained indicating that allergic reactivity was associated with increased IgE levels of defined specificity. 相似文献
8.
Wilson AD Harwood L Torsteinsdottir S Marti E 《Veterinary immunology and immunopathology》2006,112(3-4):156-170
Immunoglobulin E forms a minor component of serum antibody in mammals. In tissues IgE is bound by FcvarepsilonRI receptors on the surface of mast cells and mediates their release of inflammatory substances in response to antigen. IgE and mast cells have a central role in immunity to parasites and the pathogenesis of allergic diseases in horses and other mammals. This paper describes the production of several novel monoclonal antibodies that detect native equine IgE in immunohistology, ELISA and Western blotting. An antigen capture ELISA to quantify equine IgE in serum has been developed using two of these antibodies. The mean serum IgE concentration of a group of 122 adult horses was 23,523ng/ml with a range of 425-82,610ng/ml. Total serum IgE of healthy horses was compared with that of horses with insect bite dermal hypersensitivity (IBDH) an allergic reaction to the bites of blood feeding insects of Culicoides or Simulium spp. IBDH does not occur in Iceland where Culicoides spp. are absent, but following importation into mainland Europe native Icelandic horses have an exceptionally high incidence of this condition. In the present study Icelandic horses with IBDH had significantly higher total IgE than healthy Icelandic horse controls (P<0.05). By contrast in horses of other breeds the difference in total serum IgE between those affected with IBDH and healthy controls was not statistically significant. Total serum IgE was also monitored in a cohort of Icelandic horses prior to import into Switzerland and for a period of 3 years thereafter. High levels of serum IgE were present in all horses at the start of the study but dropped in the first year after import. Thereafter the total serum IgE remained low in Icelandic horses that remained healthy but rose significantly (P<0.05) in those that developed IBDH. These results support the conclusion that IBDH is a type I hypersensitivity response to insect allergens but indicate that IBDH in Icelandic horses may have a different pathogenesis from the same condition in other breeds. 相似文献
9.
The lesions of a seasonal dermatitis in sheep occurred mainly on the ventral surface of the animals, but in other respects they resembled those of 'sweet itch' in horses. They were primarily an immediate hypersensitivity response and the circumstantial evidence indicated that they were due to the bites of Culicoides species, possibly C obsoletus. 相似文献
10.
Hellberg W Wilson AD Mellor P Doherr MG Torsteinsdottir S Zurbriggen A Jungi T Marti E 《Veterinary immunology and immunopathology》2006,113(1-2):99-112
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
11.
Skin hypersensitivity is an allergic disease induced in horses by allergens of Culicoides midges. The condition is typically diagnosed by clinical signs and in some horses in combination with allergy testing such as intradermal skin testing or serological allergen-specific IgE determination. Here, we describe an alternative method for allergy testing: a histamine release assay (HRA) that combines the functional aspects of skin testing with the convenience of submitting a blood sample. The assay is based on the principle that crosslinking of allergen-specific IgE bound via high-affinity IgE receptors to the surfaces of mast cells and basophils induces the release of inflammatory mediators. One of these mediators is histamine. The histamine was then detected by a colorimetric enzyme-linked immunosorbent assay. The histamine assay was used to test 33 horses with skin hypersensitivity and 20 clinically healthy control animals for histamine release from their peripheral blood basophils after stimulation with Culicoides allergen extract or monoclonal anti-IgE antibody. An increased histamine release was observed in the horses with skin hypersensitivity compared to the control group after allergen-specific stimulation with Culicoides extract (p=0.023). In contrast, stimulation with anti-IgE induced similar amounts of released histamine in both groups (p=0.46). For further evaluation of the HRA, we prepared a receiver operating-characteristic (ROC) curve and performed a likelihood-ratio analysis for assay interpretation. Our results suggested that the assay is a valuable diagnostic tool to identify sensitization to Culicoides allergens in horses. Because some of the clinically healthy horses also showed sensitization to Culicoides extract, the assay cannot be used to distinguish allergic from non-allergic animals. The observation that sensitization is sometimes detectable in non-affected animals suggested that clinically healthy horses use immune mechanisms to control the reaction to Culicoides allergens that are different or absent in allergic horses. 相似文献
12.
Abstract Sixteen healthy horses with no history of skin or respiratory disease were used for an intradermal testing (IDT) threshold study, in order to determine the concentrations of 13 commercial allergenic insect extracts most appropriate for IDT. Five dilutions of each extract were used, which included the manufacturer's recommended concentrations for equine IDT, plus one dilution higher and three lower than these standard concentrations. Allergens tested included caddisfly ( Trichoptera spp.), mayfly ( Ephemeroptera spp.), horsefly ( Tabanus spp.), deerfly ( Chrysops spp.), fire ant ( Solenopsis invicta ), black ant ( Camponotus pennsylvanicus ), cockroach mix ( Periplaneta americana and Blattella germanica ), mosquito ( Aedes aegypti ), house fly ( Musca domestica ), moth ( Heterocera spp.), flea ( Ctenocephalides canis / C. felis ), Culicoides variipennis and Culicoides nubeculosis. Two separate methods were used to calculate the allergen concentration for each insect extract where the normal horses, as a group, ceased to show false-positive ('irritant') reactions. 'Irritant' threshold concentrations were determined for 9/13 of these allergens, whereas the other 4 were undetermined due to either insufficient reactivity (flea, C. variipennis ) or excessive reactivity (black ant, moth) to the concentrations tested. Recommended concentrations for future use in equine patients with suspected insect hypersensitivity include: 125 pnu mL−1 (mayfly); 250 pnu mL−1 (caddisfly, horsefly, deerfly, fire ant, house fly); 500 pnu mL−1 (cockroach); 1000 pnu mL−1 (mosquito); and 1:10 000 w/v ( C. nubeculosis ). 相似文献
13.
Ferroglio E Pregel P Accossato A Taricco I Bollo E Rossi L Trisciuoglio A 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2006,53(1):30-33
Intradermal tests were carried out on 18 horses with clinical signs of Culicoides hypersensitivity (CHS) and 23 horses without clinical signs of CHS, and sera from these horses were analysed by SDS-PAGE and Western blotting (W-B). Intradermal injections of 0.1 ml of 25 microg/microl sterile Culicoides extract, 0.1 ml of 1:10,000 histamine (positive control) and 0.1 ml of physiological saline (negative control) were made in the dermis of the middle region of the neck. Analysis of reactions indicated that a 1 cm wheal and a skinfold thickness >10% at 24 h represented a valid cut-off between horses with and without CHS. In these conditions the test, even in winter when clinical signs were absent, had 100% sensitivity and specificity. The W-B was performed after running Culicoides extract on a 12% polyacrylamide gel. The test revealed the presence of several bands with molecular weight ranging from 6 to 200 kDa. In particular, a band of 65 kDa was predominantly found in hypersensitive horses by using an anti-IgE antibody while in normal horses the same band was mainly detected by using an anti-IgG antibody. Our results demonstrated that the skin test is a valid diagnostic test, with high sensitivity and specificity and that the band of about 65 kDa probably corresponds to the allergen involved in the pathogenesis of CHS. 相似文献
14.
15.
The variations with breed, gender, age and coat colour in the prevalence of Culicoides hypersensitivity were studied in 408 horses on 18 farms in Israel. Data were gathered by means of questionnaires and the diagnoses were confirmed by direct physical examinations. The prevalence of Culicoides hypersensitivity was 28 per cent. The disease was rare on farms more than 800 m above sea level but was more prevalent at lower altitudes. The most important factors affecting the prevalence of Culicoides hypersensitivity were the farm, breed and age, but gender and colour were not significantly correlated with its prevalence. 相似文献
16.
Langner KF Darpel KE Drolet BS Fischer A Hampel S Heselhaus JE Mellor PS Mertens PP Leibold W 《Veterinary immunology and immunopathology》2008,122(1-2):126-137
The objective of this study was to compare and analyze three common diagnostic methods for summer eczema (SE) in horses, an allergic dermatitis caused by bites of Culicoides spp. Nine horses with a medical history of SE and nine control animals were intradermally challenged with whole body extracts (WBE) and the saliva of a native (C. nubeculosus) and exotic (C. sonorensis) Culicoides species. Blood and serum samples of the horses were examined for basophil reactivity by a histamine release test (HRT) and for Culicoides-specific serum immunoglobulin E (IgE) and G (IgG) by enzyme-linked immunosorbent assay (ELISA). The results of intradermal testing (IDT) at 30min (immediate reactivity) and 4h (late-phase reactivity) post challenge with most insect preparations revealed significant differences between horses with and without SE. Overall, the HRT showed the most accurate results with a sensitivity of 1.00 for all Culicoides preparations and specificities of 0.78 (WBE) and 1.00 (saliva). By contrast, delayed reactions of the IDT (24h), and levels of Culicoides-specific IgE and IgG in the native serum showed little or no distinction between allergic and non-allergic horses. However, the use of purified serum IgE and IgG indicated the possibility for elevated titers of insect-specific serum immunoglobulins in horses with SE. The IDT and HRT did not reveal obvious differences in onset and intensity of positive reactions for the native verses exotic Culicoides species, whereas the ELISA showed slightly higher numbers of positive reactions for serum IgG with the indigenous species. Saliva, as compared to WBE, was found to have improved sensitivity and/or specificity for the HRT and for the late-phase immune reactions as measured by the IDT. Overall, the results indicate that allergy tests utilizing effector cells (mast cells, basophils) are more accurate in diagnosing SE in horses than serological analysis by ELISA. 相似文献
17.
Culicoides hypersensitivity in the horse: 15 cases in southwestern british columbia 总被引：2，自引：1，他引：1 
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下载免费PDF全文 Kleider N Lees MJ 《The Canadian veterinary journal. La revue veterinaire canadienne》1984,25(1):26-30,31-32
The investigation of a chronic, seasonal dermatitis of horses in southwestern British Columbia is described. Typically the history indicated an insidious onset, followed by a gradual progression in the severity of the signs each year. Lesions appeared during the warmer months of the year and tended to regress during the winter. The clinical signs consisted of areas of pruritus and excoriation, affecting predominantly the ventral midline, mane and tailhead. In all cases corticosteroid therapy relieved the pruritus and allowed the lesions to heal.
The salient pathological findings were hyperkeratosis, spongiosis and a dermal infiltration of eosinophils together with mononuclear cells. These changes are typical of an allergic dermatitis, which has been recognized in many parts of the world as a hypersensitivity reaction to the bites of Culicoides spp. In this instance, the epidemiological findings relating to the geographic area, the local insect population and the distribution of lesions implicated Culicoides obsoletus as the etiological agent.
相似文献18.
Dermal reactivity to histamine, serotonin and bradykinin in relation to allergic skin reactions of the horse 总被引：1，自引：0，他引：1
ALEX MORROW PATRICK J. QUINN KENNETH P. BAKER 《Journal of veterinary pharmacology and therapeutics》1986,9(1):40-48
The reactivity of horse skin to intradermal inoculation of histamine, serotonin and bradykinin was investigated, and the resulting reactions compared with those produced in the same horses by a 1% whole-body extract of Culicoides. Both histamine and bradykinin produced large reactions, but there was no significant correlation between the dermal responsiveness to insect allergen and either histamine or bradykinin. Two anti-histamine drugs (promethazine hydrochloride and tripelennamine hydrochloride) were effective in reducing the reaction produced by the insect extract. 相似文献
19.
Spier SJ Leutenegger CM Carroll SP Loye JE Pusterla JB Carpenter TE Mihalyi JE Madigan JE 《American journal of veterinary research》2004,65(6):829-834
OBJECTIVE: To develop and use a sensitive molecular assay for detecting the phospholipase D (PLD) exotoxin gene of Corynebacterium pseudotuberculosis in an attempt to identify insect vectors that may be important in transmission of clinical disease in horses. SAMPLE POPULATION: 2,621 flies of various species. PROCEDURE: A real-time polymerase chain reaction (PCR)-based fluorogenic 5' nuclease (TaqMan) system (ie, TaqMan PCR assay) was developed for the detection of the PLD gene in insects. Flies were collected monthly (May to November 2002) from 5 farms in northern California where C. pseudotuberculosis infection in horses is endemic. Three of the 5 farms (which housed a total of 358 horses) had diseased horses during the study period. A total of 2,621 flies of various species were tested for the PLD gene of C. pseudotuberculosis. RESULTS: Evidence of bacterial DNA for the PLD gene was detected in skin biopsy specimens from clinically affected horses and from 3 fly species collected from farms where affected horses were housed. Farms with a high incidence of diseased horses had a high proportion of insects carrying the organism. High percentages of flies with positive results for the PLD gene were observed in October, when most clinically affected horses were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Our results are consistent with the hypothesis that C. pseudotuberculosis may be vectored to horses by flies. Three potential vectors were identified, including Haematobia irritans, Stomoxys calcitrans, and Musca domestica. The organism can be identified in up to 20% of house flies (Musca domestica) in the vicinity of diseased horses. 相似文献
20.
Insect bite hypersensitivity (IBH) is an IgE-mediated dermatitis caused by bites of midges from the genus Culicoides. We have shown previously that peripheral blood mononuclear cells (PBMC) from IBH-affected horses produce higher levels of IL-4 and lower levels of IL-10 and TGF-β1 than those from healthy horses, suggesting that IBH is associated with a reduced regulatory immune response. FoxP3 is a crucial marker of regulatory T cells (Tregs). Here we have determined the proportion of CD4(+)CD25(+)FoxP3(+) T cells by flow cytometry in PBMC directly after isolation or after stimulation with Culicoides extract or a control antigen (Tetanus Toxoid). There were no differences between healthy and IBH horses either in the proportion of FoxP3(+)CD4(+)CD25(+) cells in freshly isolated PBMC or in the following stimulation with Tetanus Toxoid. However, upon stimulation of PBMC with the allergen, expression of FoxP3 by CD4(+)CD25(+high) and CD4(+)CD25(+dim) cells was significantly higher in healthy than in IBH horses. Addition of recombinant IL-4 to PBMC from healthy horses stimulated with the allergen significantly decreased the proportion of FoxP3 expressing cells within CD4(+)CD25(+high). These results suggest that IBH is associated with a decreased number of allergen-induced Tregs. This could be a consequence of the increased IL-4 production by PBMC of IBH-affected horses. 相似文献