Aggravation of bronchial eosinophilia in mice by nasal and bronchial exposure to Staphylococcus aureus enterotoxin B

BACKGROUND: The role of bacterial enterotoxins like Staphylococcus aureus enterotoxin B (SEB) in allergic asthma remains unknown. We used a mouse model of airway allergy to study the effects of nasal or bronchial contact with SEB on bronchial allergic inflammation. METHODS: The features of allergic asthma were induced in ovalbumin (OVA)-sensitized mice (days 1-13) by repeated exposures to nebulized OVA (days 33-37). Nasal or bronchial application of SEB was performed on three occasions (days 33-35-37), and the effects on bronchial inflammation, IgE titres and expression levels of mRNA for T helper type 2 cytokines and other inflammatory mediators were evaluated. RESULTS: Both nasal and bronchial SEB enhanced the allergen-induced bronchial inflammation, as reflected by more eosinophilic inflammation in the airway lumen and in bronchial tissue. Aggravation of experimental asthma correlated with higher expression of mRNA for IL-5, IL-4, IFN-gamma, IL-12 p40, eotaxin-1 and TGF-beta in bronchi. In addition, nasal SEB elevated concentrations of IL-4, IL-5 and IFN-gamma in serum and bronchial SEB increased titres of OVA-specific and total IgE in serum. CONCLUSION: Our data illustrate the potential of both nasal as well as bronchial SEB to aggravate several features of allergic asthma in a mouse model.     

Nasal carriage of Staphylococcus aureus in house dust mite allergic patients and healthy controls

BACKGROUND: Staphylococcal colonization may influence the course of allergic diseases such as atopic dermatitis or allergic rhinitis. The frequency of Staphylococcus aureus (SA) nasal carriage and its possible influence on persistent allergic rhinitis was investigated. METHODS: In nasal lavages from 22 patients with house dust mite allergy and 18 healthy controls, the number of SA colony forming units per ml were assessed and related to nasal symptom scores, the concentrations of three inflammatory cell activation markers, nasal total IgE and 17 cytokines in nasal secretions. RESULTS: SA was found in 15/22 allergic patients and 4/18 controls (P < 0.01). Comparing allergic SA carriers with allergic noncarriers, nasal symptom scores tended to be higher (P < 0.1), and the cell activation markers ECP (10(2.23+/-0.33)vs 10(1.45+/-0.50) ng/ml; P < 0.05) and elastase (10(2.70+/-0.21)vs 10(2.12+/-0.34) ng/ml; P < 0.01), and nasal total IgE-levels (10(1.66+/-0.38)vs 10(1.2+/-0.28) kU/ml; P < 0.05) were significantly higher in allergic SA carriers. Nasal SA carriers had a higher nasal IL-13/IFN-gamma ratio (P < 0.01), and this was correlated with higher nasal total IgE in allergic patients (r = 0.6, P < 0.05). CONCLUSION: Nasal SA carriage is frequent in patients with persistent allergic rhinitis. The data of this study suggest that they are not only secondary bystanders, but actively modulate the disease by promoting local IgE production.     

金黄色葡萄球菌肠毒素B在变态反应性疾病发病机制中的作用

变态反应性疾病的发病率逐年上升,Ⅰ型超敏反应是其主要的发病机制。近年来研究发现,金黄色葡萄球菌肠毒素B不但可以作为变应原诱导变态反应性疾病的发生,而且还可以作为超抗原影响免疫调节细胞和促炎细胞活性,在变态反应性疾病中发挥极其重要的作用。本文对金黄色葡萄球菌肠毒素B在变应性鼻炎、哮喘及特应性皮炎几种常见变态反应性疾病发生、发展中的作用机制作一综述。     

Severe atopic dermatitis is associated with sensitization to staphylococcal enterotoxin B (SEB)

BACKGROUND: Staphylococcus aureus has been identified as a possible trigger factor in atopic dermatitis (AD). Some 30-60% of S. aureus strains isolated from patients with AD are able to produce exotoxins with superantigenic properties, mostly staphylococcal enterotoxins A, B, C, and D (SEA-D) and toxic shock syndrome toxin-1 (TSST-1). Recently, it was demonstrated that the presence of IgE antibodies to SEA and SEB is correlated with the severity of skin lesions in children with AD. To determine the relevance of staphylococcal enterotoxins in adult patients with AD, we investigated the relationship between the severity of skin lesions and sensitization to SEA and SEB. METHODS: Clinical severity was determined by the SCORAD index. Circulating IgE antibodies to SEA and SEB, serum eosinophil cationic protein (ECP) levels, and urine eosinophil protein X (EPX) levels were measured. RESULTS: The skin condition was significantly worse in patients sensitized to SEB than in unsensitized patients. Serum ECP and urine EPX levels were found to be significantly higher in SEB-sensitized patients, confirming the higher degree of cutaneous inflammation. CONCLUSIONS: Our results demonstrate a relationship between severity of skin lesions and sensitization to SEB in adult patients with AD, but a relationship between disease activity and sensitization to SEA could not be shown.     

Efficacy of probiotic Lactobacillus GG on allergic sensitization and asthma in infants at risk

Background Probiotics are perceived to exert beneficial effects in the prevention and treatment of allergic diseases. Objective There are conflicting data from studies as to an impact on allergic sensitization and asthma. Methods Our prospective double‐blind study randomly assigned 131 children (6–24 months old) with at least two wheezing episodes and a first‐degree family history of atopic disease to 6 months of Lactobacillus rhamnosus (LGG, 10¹⁰ colony forming units) or placebo. Atopic dermatitis and asthma‐related events (e.g. need of inhalation, symptom‐free days) were documented throughout the intervention and 6‐month follow‐up. We determined IgE, a representative panel of specific IgE, eosinophils, eosinophilic cationic protein, and TGF‐β before, at the end of intervention, and after 6 months of follow‐up. Results There were no significant differences as to atopic dermatitis or asthma‐related events. In a subgroup with antecedent allergic sensitizations, asthmatic complaints were even slightly worse. We found fewer sensitizations towards aeroallergens after 6 months of LGG (P=0.027) and after 6 months of follow‐up (P=0.03). Supplementation was well‐tolerated and no severe adverse events occurred. Conclusions In young children with recurrent wheeze and an atopic family history, oral LGG had no clinical effect on atopic dermatitis or asthma‐related events, and only mild effects on allergic sensitization. This effect persisted 6 months after the cessation of the supplementation. Cite this as: M. A. Rose, F. Stieglitz, A. Köksal, R. Schubert, J. Schulze and S. Zielen, Clinical & Experimental Allergy, 2010 (40) 1398–1405.     

Children with atopic dermatitis who carry toxin-positive Staphylococcus aureus strains have an expansion of blood CD5- B lymphocytes without an increase in disease severity

Toxin-positive strains of Staphylococcus aureus (T + S. aureus) are present on the skin of some but not all patients with atopic dermatitis. Many staphylococcal toxins are superantigens, which can stimulate the immune response and thus may potentially lead to the very high levels of IgE characteristic of this condition, as well as exacerbating the clinical disease. The aim of this study was to determine whether the presence of T + S. aureus on the skin of children with atopic dermatitis was associated with in vivo evidence of a heightened humoral immune response, higher IgE levels and more severe clinical disease. Toxin gene expression in S. aureus isolated from the eczematous lesions of 28 children with atopic dermatitis was assessed by PCR. Clinical and immune data were also collected from this cohort. Thirteen of the 28 children (46%) were colonized with T + S. aureus strains. The presence of T + S. aureus was associated with a significant expansion in peripheral blood CD5- B cells (P = 0.01), and the more toxin types identified the greater the B-cell expansion (P = 0.002). However, in this cohort of children with atopic dermatitis, despite th in vivo expansion of B cells in children harbouring T + S. aureus, there was no associated increase in IgE levels or in clinical disease severity scores.     

Austrian children living on a farm have less hay fever, asthma and allergic sensitization

BACKGROUND AND OBJECTIVES: In some studies, the prevalence of hay fever and asthma has been found to be lower in children from rural areas than in children from an urban environment. We hypothesized that living on a farm might be protective against development of allergic sensitization and allergic diseases. METHODS: In a cross-sectional survey, parents of 2283 children aged 8-10 years from a mostly rural area in Austria answered a standardized questionnaire on allergic diseases and environmental factors. 1137 children performed a skin prick test to seven local allergens. RESULTS: The prevalence of hay fever (3.1 vs 10.3%, P = 0.0002), asthma (1.1 vs 3.9%, P = 0.017) and a positive skin prick reactivity to at least one of the common local allergens (18.8 vs 32.7%, P = 0. 001) was significantly lower in children living on a farm than in children from a non-farming environment. In a multivariate logistic regression model, adjusting for genetic background, parent education, living and housing conditions and dietary factors did not change the odds ratio for the association of farming and allergic sensitization. Only after including 'regular contact with livestock and poultry' into the model did the odds ratio change significantly (cOR 0.48 95% CI 0.30-0.75 to aOR 0.75 95% CI 0.37-1.52) indicating an association between regular contact with farm animals and reduced risk of atopic sensitization. CONCLUSION: Possible explanations for the lower prevalence of hay fever, asthma and allergic sensitization in children living on a farm might be the development of immunotolerance or the stimulation of TH1 cells and suppression of TH2 cells by increased exposure of farm children to microbial antigens in the stables or farmhouses.     

重组金黄色葡萄球菌肠毒素B蛋白可溶性微针制备及免疫效果研究

目的建立重组金黄色葡萄球菌肠毒素B(SEB)蛋白的可溶性微针体外检测方法及体内免疫效果评价。方法通过动态光散射(DLS)检测蛋白粒径、BCA法检测单片微针的蛋白浓度、活体成像实验检测微针皮内注射后蛋白在体内的停留时间,通过DRIZE评分评价微针注射后的皮肤情况,通过动物实验评价重组SEB蛋白可溶性微针的免疫原性及免疫保护效果。结果DLS分析显示SEB蛋白可溶性微针负载的重组SEB蛋白粒径与重组SEB蛋白溶液中的SEB蛋白粒径无明显差别,单片微针中重组SEB蛋白含量为(13.2±1.4)μg,活体成像实验显示相对于肌肉注射,重组SEB蛋白可溶性微针皮内给药后荧光蛋白在体内的停留时间延长,动物实验显示13.0μg的重组SEB蛋白可溶性微针即能引发免疫反应,并且在2LD50SEB攻毒剂量下能够产生很好保护效果。结论重组SEB蛋白可溶性微针能够刺激小鼠机体产生较好的免疫原性及免疫保护效果,为发展疫苗新型免疫途径提供了新策略。     

金葡菌肠毒素B在烫伤脓毒症大鼠早期肠损害中的作用及意义

目的：探讨金黄色葡萄球菌肠毒素B(SEB)在烫伤脓毒症大鼠早期肠损害中的作用。方法：雄性Wistar大鼠86只，随机分为正常对照组（n=10）、烫伤对照组（n=10）、烫伤后金葡菌感染组（n=50）和SEB单克隆抗体（单抗）拮抗组（n=16）。留取血样品测定SEB、内毒素、肿瘤坏死因子-α（TNF-α）和干扰素-γ（IFN-γ）水平；同时测定组织内毒素水平及小肠组织二胺氧化酶（DAO）活性。结果：烫伤后金葡菌感染动物血浆SEB、TNF-α和IFN-γ水平均显著高于正常对照组，并于2 h、6 h达峰值（P<0.05或P<0.01），此后降低；而小肠组织DAO活性则持续低于对照组（P<0.05）。相关分析显示，小肠组织DAO活性与血浆SEB水平呈显著负相关（r=-0.4398，P<0.05）。此外，金葡菌攻击后动物血浆及心、肝、肺、肾等组织中内毒素含量亦明显高于正常和烫伤对照组水平（P<0.05）；SEB单抗干预可不同程度抑制血浆及组织内毒素水平的变化，其中伤后2 h肾脏改变显著（P<0.05）。结论：在严重烫伤后金葡菌感染时，金葡菌的重要致病因子－SEB可加重动物小肠粘膜屏障功能损害，促进肠源性内毒素移位并蓄积于局部组织，后者可能与金葡菌致病因子协同作用导致脓毒症的病理生理过程进一步恶化。     

金黄色葡萄球菌及其肠毒素B对慢性实验性哮喘小鼠的影响

目的探索金黄色葡萄球菌肠毒素B（SEB）对实验性支气管哮喘小鼠肺组织Th0细胞分化的在体调节和对气道炎症的作用。方法32只15～17dBALB／c小鼠，随机分为4组：对照组、模型组、金黄色葡萄球菌组、金黄色葡萄球菌肠毒素B（SEB）组。用卵蛋白（OVA）致敏和激发建立小鼠慢性哮喘模型，在致敏前14d对幼年鼠做金黄色葡萄球菌或SEB预防性腹腔注射。观察记录小鼠的耗氧量、肺组织切片、支气管肺泡灌洗液（BALF）中炎性细胞及相关细胞因子等的改变。结果金黄色葡萄球菌组与模型组相比，肺组织病理切片结构紊乱减轻、炎症细胞明显减少，小鼠耗氧量降低（5．24±0．12vs5．59±0．18），BALF中IL-4水平明显下降（44．94±4．51vs29．37±4．17），IFN-γ水平明显增加（19．61±3．83vs29．33±4．04），SEB组也有上述作用（耗氧量：5．09±0.20；细胞介素4：36．68±5．10；γ干扰素：24．27±3．46）。结论金黄色葡萄球菌能明显减轻实验性哮喘的气道炎症，纠正哮喘小鼠肺组织中Th1／Th2细胞因子的失衡，其作用可能是通过其分泌的SEB。     

重组金黄色葡萄球菌肠毒素C3生物学活性的初步研究

目的:表达和纯化重组金黄色葡萄球菌肠毒素C3(rSEC3),并初步探讨rSEC3的生物学活性。方法:将转化有pET-32a(+)-SEC3重组质粒的大肠杆菌BL21经IPTG诱导表达、纯化后,MTT法检测0.1、0.5、1、5、10、50、100μg/ml的rSEC3促进人外周血单个核细胞(PBMC)增殖及抑制人宫颈癌细胞(Hela细胞)、人食管癌细胞(KYSE细胞)的作用。结果:重组金黄色葡萄球菌肠毒素C3在大肠杆菌BL21中成功表达。与空白对照相比,0.1～100μg/ml的rSEC3对PBMC均有显著的促增殖作用(P<0.05),1μg/ml时促增殖作用最强(t=113.851,P=0.000),和100μg/ml PHA作用相似(t=0.693,P=0.527)。以Hela细胞为靶细胞,培养48小时后,与空白对照相比,0.5、1、5μg/ml的rSEC3能显著增强PBMC对Hela细胞杀伤作用(P<0.05),抑瘤率分别为(70.44±9.27)%、(93.65±8.05)%、(103.40±6.65)%;以KYSE细胞为靶细胞,与空白对照相比,3个浓度的rSEC3也都有抑瘤作用(P<0.05),抑瘤率分别为(28.10±2.72)%、(46.62±4.17)%、(19.35±3.05)%。结论:rSEC3蛋白具有良好促人外周血单个核细胞增殖活性,并能够增强PBMC对肿瘤细胞的杀伤活性。