水稻(Oryzasativa L.)潜在内源性致敏原的生物信息学筛选与分析

食物中的蛋白质是最常见的食入性致敏原。为了对水稻中的内源性致敏原有一个全面的认识和了解,本研究利用全序列比对的方法比较了水稻蛋白与已知致敏原之间的序列相似性,获得了水稻潜在致敏原,并对其保守结构域、分子功能、系统发育和染色体分布进行了分析和描述。结果一共发现了122个水稻潜在致敏蛋白,其中包括了22个已被数据库收录的水稻致敏原;保守结构域分析显示它们分别属于37个蛋白家族,其中的HATPase_c_3(Histidine kinase-,DNA gyrase B-,and HSP90-like ATPase,PF13589)结构域未在已知致敏原中发现;系统发育分析则分别揭示了水稻Prolamin蛋白超家族和Dna K蛋白家族的多样性;而且潜在致敏蛋白在水稻染色体上有成簇状分布的趋势。     

食物不耐受导致变态反应性皮肤病的临床观察

目的:探讨血清中14种食物特异性IgG抗体与变态反应性皮肤病的相关性.为临床诊治提供依据.方法:应用酶联免疫吸附法,检测120例变态反应性皮肤病患者(荨麻疹40例,湿疹50例,过敏性紫癜30例)血清中14种食物变应原IgG浓度,另设正常对照组20例,按疾病分组观察并比较血清检测结果.结果:120例患者14种食物变应原血清不耐受抗体IgG检测结果阳性率依次为:牛肉,鸡肉,鳕鱼,玉米,螃蟹,鸡蛋,蘑菇,牛奶,猪肉,大米,虾,大豆,西红柿,小麦.结果表明,病例中以鸡蛋、虾、螃蟹的致敏性较高(阳性率比较差别显著,P<0.0001);小麦、牛奶、西红柿和蘑菇的致敏性次之(阳性率比较差别显著,P<0.0001);牛肉、鸡肉、鳕鱼、玉米、猪肉、大米、大豆致敏性较低(阳性率比较差别显著,P<0.0001).结论:变态反应性皮肤病患者体内特异性IgG抗体阳性率高,提示与食物不耐受有关,对临床变态反应性皮肤痛的饮食指导有重要意义.检测血清食物变应原不耐受抗体IgG可以尽早发现患者的致敏食物确定疾病病因,及时将致敏食物从患者食谱中排除,降低患者食物过敏的患病率,缓解临床症状,从而降低变态反应性皮肤病的发病率.     

两品系小鼠食物过敏模型的比较

目的比较两种不同品系小鼠食物过敏模型的敏感性和肠道菌群变化的差异,旨在为食物过敏模型的建立提供依据。方法分别对30只4~5周龄BALB/c和KM雌鼠用卵清蛋白(ovalbumin,OVA)致敏建立食物过敏模型,ELISA法检测小鼠血清OVA特异性IgE水平;HE染色观察空肠组织形态;采用DGGE技术检测粪便菌群的变化。结果 (1)30只致敏的BALB/c小鼠中有27只血清OVA特异性IgE水平明显升高(P0.001),而30只致敏的KM小鼠中有21只,且BALB/c小鼠空肠绒毛炎症细胞浸润、上皮脱落及坏死比KM小鼠明显;(2)食物过敏造模后,BALB/c小鼠肠道菌群的改变明显(P0.001),而KM小鼠中仅有均匀度改变显著(P0.05);(3)BALB/c小鼠和KM小鼠对照组肠道菌群的丰富度、Shannon指数及均匀度都有差异。结论 BALB/c小鼠对OVA的敏感性高于KM小鼠,不同品系小鼠肠道菌群结构不同,OVA处理后,BALB/c小鼠菌群的改变比KM小鼠更明显。     

肠道益生菌预防和治疗食物过敏的研究进展

目前 ,食物过敏的发生率在人群 ,尤其是婴幼儿中逐年增高。其治疗策略仍是以排除致敏食物为主 ,但效果欠佳。由于益生菌所独有的生物学特点和肠道粘膜免疫反应的特异性 ,使肠道益生菌疗法作为治疗食物过敏的一种新兴疗法 ,日益受到人体的重视。本文就其临床疗效、作用机制、选菌原则、使用安全性等问题作一综述 ,以期加强对益生菌的研究和应用。1　益生菌治疗食物过敏的疗效研究进展益生菌在人体中主要以双歧杆菌和乳酸杆菌为主 ,具有粘附肠粘膜、稳定胆汁酸、使用安全 ,是人类肠道共生细菌等共同特点。作为肠道微生态的平衡者和肠道粘膜免…     

食物过敏原研究进展

食物过敏反应是世界各地普遍存在的一个严重问题。本文综述了目前有关食物过敏原研究所取得的进展。包括食物过敏反应流行病学数据,食物过敏原,新过敏原的引物及其监控,通过消除内源基因根除过敏性,移去过敏性抗原基等。     

食物抗原特异性IgE测定在预测特异性皮炎患儿食物过敏发生风险的价值

目的：检测特异性皮炎（atopic dermatitis,AD）患儿食物抗原特异性免疫球蛋白E（sIgE）的浓度能否预测临床过敏的发生。方法：纳入兰州市第一人民医院招募的婴儿患者（1～18个月）327名,在24个月的随机双盲阶段后,是持续12个月的开放标签（OL）阶段,再进行食物的过敏发展。此外,在基线、双盲和OL阶段结束时,测量牛奶、蛋清、花生、小麦、海鲜混合物和大豆的sIgE。 结果：到OL阶段结束时,15.9%的AD患儿发生至少1种食物过敏,最常见的食物过敏是花生、牛奶和蛋清,分别占6.6%、4.3%和3.9%［17］。海鲜、大豆和小麦过敏比较罕见。牛奶、鸡蛋和花生的sIgE水平随AD的严重程度而增加。牛奶、花生、蛋清和海产品混合物的基线sIgE值与这些食物发生过敏的风险在统计学上具有相关性（P<0.05）。AD的严重程度较高（IGA）也可以预测食物过敏的发生。ROC值下的面积显示,基线sIgE预测花生、牛奶和蛋清的食物过敏的准确率高,但不适用于海鲜、小麦或大豆。结论：在有大量发生食物过敏风险的婴儿中,sIgE水平对于预测食物过敏的发展无临床意义。     

Science:血细胞类型决定是否食物过敏

正有些小孩子可以一手抓一大把的花生,但对其他小孩子来说医科花生就有可能是致命的。最近一项研究揭示了为什么有的小孩子会得食物过敏症状:刚出生时,他们的血液中就具有大量能够引发超敏反应的细胞。过去一段时间内,对差不多6百万食物过敏儿童的大量研究发现:食物过敏症状其实从很早的时候就开始存在了。通过采集婴儿脐带束中的血液,研究者们对小孩子的免疫系统做了初步的了解。他们发现:后期产生食物过敏反应的儿童在刚出生时血液中就具有大量促炎性信号,他们     

昆明鼠气道致敏模型的建立

目的 建立昆明鼠气道致敏模型。方法 对昆明鼠(实验、对照组各10只)进行了卵清蛋白喷雾致敏,检测了肺组胺浓度,淋巴细胞在体外对OVA的特异性转化,体外抗体生成。并对肺组织作病理学检查。结果 发现上述各项指标实验组较对照组均有明显差异。结论 可以初步肯定通过该致敏途径建立的模型成立。     

高效液相色谱法测定乳清蛋白中的α-乳白蛋白和β-乳球蛋白及其改性降敏

牛乳过敏是由牛乳中的致敏蛋白引起的一种不良反应,而乳清蛋白是从牛奶中分离的高营养价值的蛋白。本研究中,笔者建立了一种高效液相色谱技术定量检测乳清蛋白中主要致敏蛋白α-乳白蛋白和β-乳球蛋白的方法;与现行标准(T/TDSTIA 007—2019)相比,本方法采用应用更广泛的Sepax-C8(4. 6 mm×150 mm,5μm)色谱柱,以0. 1%的三氟乙酸水溶液(A)和0. 1%的三氟乙酸乙腈溶液(B)作为流动相进行梯度洗脱,色谱柱在温度28℃、波长280 nm检测条件下对目标蛋白进行分离检测。定量分析结果表明,致敏蛋白在0. 125～2. 000 mg/m L范围内与蛋白峰面积线性关系良好(R2 0. 99),蛋白平均回收率为92%～96%,α-乳白蛋白和β-乳球蛋白检出限分别为0. 078和0. 090 mg/m L。该检测方法重复性好,可用于α-乳白蛋白和β-乳球蛋白的定量分析测定。此外,考察了胰蛋白酶对2种致敏蛋白改性的影响,采用智能可视化优化方法预测出酶解最优条件,结果表明在45℃下加入2000 U/g的胰蛋白酶水解30 min后,水解率高达78. 9%,2种致敏蛋白含量占牛乳总蛋白的22. 7%,大大降低了乳制品中的致敏蛋白含量。     

高脂饮食诱导肠道微生物代谢产物短链脂肪酸改变进而影响食物过敏的发生

通过回顾过敏性疾病以及高脂饮食、肥胖等的大量研究报告,探究高脂饮食以及高脂饮食带来的肥胖是否会对食物过敏的发生产生影响以及可能的机制。研究发现,高脂饮食可能会增加食物过敏发生率,降低食物过敏阈值,增加食物过敏的风险,并且高脂饮食对肠道微生物的影响是其中的一个原因。高脂饮食改变肠道微生物结构,导致短链脂肪酸产生差异,而短链脂肪酸通过G蛋白偶联受体、组蛋白乙酰化等途径引起Treg细胞分化、IgA产生以及致耐受性的DC细胞产生,影响肠道屏障的健康,因此,高脂饮食对肠道微生物结构的改变带来的短链脂肪酸的产生差异影响了肠道屏障的健康,进而导致食物过敏的阈值降低,易感性增加。     

Value of eight-amino-acid matches in predicting the allergenicity status of proteins: an empirical bioinformatic investigation

Food allergies affect an estimated 3 to 4% of adults and up to 8% of children in developed western countries. Results from in vitro simulated gastric digestion studies with purified proteins are routinely used to assess the allergenic potential of novel food proteins. The digestion of purified proteins in simulated gastric fluid typically progresses in an exponential fashion allowing persistence to be quantified using pseudo-first-order rate constants or half lives. However, the persistence of purified proteins in simulated gastric fluid is a poor predictor of the allergenic status of food proteins, potentially due to food matrix effects that can be significant in vivo. The evaluation of the persistence of novel proteins in whole, prepared food exposed to simulated gastric fluid may provide a more correlative result, but such assays should be thoroughly validated to demonstrate a predictive capacity before they are accepted to predict the allergenic potential of novel food proteins.     

Fruit cross-reactive allergens: a theme of uprising interest for consumers' health

Regular consumption of fruits has a positive influence on human health by disease prevention. However parallel to dietetic benefits, IgE-mediated fruit allergies have been shown to be an increasing health risk for children and adults in the Northern hemisphere. The spectrum of food allergies ranges from chronic symptoms to more acute problems and even anaphylaxis. Fruit proteins with high primary sequence similarity display also homologous tertiary structures, resulting in similar epitopes to IgEs and consequently in cross-reactivity. In this review we present the major allergens of stone and pome fruits and discuss the presence of homologous proteins in small fruits. Interestingly these proteins, which might pose an allergenic potential for pre-sensitised individuals are expressed also in strawberry, raspberry and blueberry, otherwise rich in beneficial biofactors.     

Identification of the 7S and 11S globulins as percutaneously sensitizing soybean allergens as demonstrated through epidermal application of crude soybean extract

Cutaneous exposure to food allergens can predispose individuals to food allergies. Soybean, a major allergenic food, is an ingredient in various cosmetic products. However, the types of soybean proteins that are percutaneously sensitizing in humans or animal models remain unknown. In this study, BALB/c mice were dorsally shaved and epicutaneously exposed to a crude soybean extract including sodium dodecyl sulfate or distilled water alone. Specific IgEs secreted in response to 7S globulin (Gly m 5), 11S globulin (Gly m 6), Gly m 3, and Gly m 4 were measured using enzyme-linked immunosorbent assays or immunoblots. Exposure to soybean extract elicited the secretion of soybean-specific IgEs. Of the soybean proteins, 7S and 11S globulins acted as percutaneous sensitizers in 6/9 mice (67%). Additionally, IgE bound specifically and preferentially to the 7S globulin β subunit. In conclusion, this is the first report to identify percutaneously sensitizing soybean allergens in a mouse model.     

Immunological identification and characterization of individual food allergens

Food allergies of type-I-allergy are immunoglobulin E (IgE) mediated and caused by certain proteins or glycoproteins, which are called food allergens. An analytical marker of allergens is the IgE-reactivity to these substances. Normally food allergens are minor components in allergenic source material, which consist of a huge number of chemical different substances. Thus allergen extraction, separation and immunological detection methods are described which identify and characterize individual food allergens by a minimum of manipulation. Favoured separation methods of allergenic extracts are electrophoretic ones allowing the combination of highly resolved protein separations with immunological detection methods subsumed by the term immunoblotting. These techniques are a useful basis to characterize allergens by chemical methods. Once the primary protein structure of a food allergen is established, the way is cleared for the identification of epitopes. Epitopes are immunological detectable parts of a protein or glycoprotein generating the interface between chemical structure and immune-system. The nature of epitopes may differ, for instance, can be conformational, continuous, or built up by glycoconjugates, which determine the stability of food allergens, especially in the case of food processing. Progress in identification and characterization of food allergens will improve diagnostics and therapy of food allergy.     

Monitoring pollinosis and airborne pollen in a Rome university

Pollen allergies and airborne pollen weremonitored at the University of Rome ``TorVergata' in 1999 in order to determine theconcentration and the quality of airbornepollen belonging to allergenic plants inrelationship to the prevalence of pollenallergies.Airborne pollen was monitored by volumetrictrap while data on allergies were collectedthrough a questionnaire distributed to theUniversity personnel belonging to variousworking categories. Meteorological data wereobtained through a daily monitoring carried outby a meteorological station while plantanthesis identification was done at theHerbarium of the University.Results indicated that prevalent allergies weredue to Gramineae, Urticaceae and Oleaceaepollen. Many subjects suffering from allergiesdid not know the responsible allergen(s) andmore than half of the allergic subjects statedto have allergic relatives.Data on pollen monitoring and prevalence ofallergies, collected in the same geographicalarea, were found to be in accordance with eachother, with the exception of the case ofCupressaceae/Taxaceae plants, whose pollen wasfound in high concentration although no case ofallergy due to this pollen was established.     

Focus: Allergic Diseases and Type II Immunity: Allergies and Adaptations: A Perspective on the Need for Culturally Responsive Care to Medically Indicated Dietary Restrictions

In medicine, we tend to think of food as being equivalent to nutrition, and food allergies are understood primarily as a biomedical process. In this piece, I explore how my experience with food allergies intersects with my cultural identity as a second-generation Indian-American. I also offer insights from my experiences in medical training and practice and reflect on the responsibility of health providers to understand the social and cultural context of food allergies.     

The importance of cultivated land for spreading of allergenic plants in Italy

We studied the ecological characteristics of the plants of Italian cultivated land that cause allergies in sensitized individuals. Differences between the allergenic flora of annual and perennial cultivations were found. Prevalence of annual therophytes was found in seasonal and annual crops subjected to soil tillage and to strong human disturbance. Plants growing in stable, moderately disturbed cultivations (citrus and olive groves, vineyards) were more often perennials. Allergenic species dispersed by wind and those endowed with multiple dispersal strategies (polychory) were well represented in seasonal and annual crops. The moderate height of these cultivations facilitates circulation of air, favouring the diffusion of anemochoric plants, which explains the abundance of the Poaceae and the Asteraceae families. The spreading of some allochthonous invasive allergenic species was ascertained. The entrance of allergenic plants from surrounding natural ecosystems increases the overall allergenicity of Italian cultivations. The results obtained pointed out a strong relationship between allergenic flora, human impact, and the structure of the cultivations. They point out the importance of knowledge about the ecological characteristics of the allergenic flora infesting the cultivations, which enables efficacious control of the diffusion of the most dangerous species.     

Changes in atmospheric CO2 influence the allergenicity of Aspergillus fumigatus

Increased susceptibility to allergies has been documented in the Western world in recent decades. However, a comprehensive understanding of its causes is not yet available. It is therefore essential to understand trends and mechanisms of allergy‐inducing agents, such as fungal conidia. In this study, we investigated the hypothesis that environmental conditions linked to global atmospheric changes can affect the allergenicity of Aspergillus fumigatus, a common allergenic fungal species in indoor and outdoor environments and in airborne particulate matter. We show that fungi grown under present‐day CO₂ levels (392 ppm) exhibit 8.5 and 3.5 fold higher allergenicity compared to fungi grown at preindustrial (280 ppm) and double (560 ppm) CO₂ levels, respectively. A corresponding trend is observed in the expression of genes encoding for known allergenic proteins and in the major allergen Asp f1 concentrations, possibly due to physiological changes such as respiration rates and the nitrogen content of the fungus, influenced by the CO₂ concentrations. Increased carbon and nitrogen levels in the growth medium also lead to a significant increase in the allergenicity. We propose that climatic changes such as increasing atmospheric CO₂ levels and changes in the fungal growth medium may impact the ability of allergenic fungi such as A. fumigatus to induce allergies.     

Structure and stability of 2S albumin-type peanut allergens: implications for the severity of peanut allergic reactions

Resistance to proteolytic enzymes and heat is thought to be a prerequisite property of food allergens. Allergens from peanut (Arachis hypogaea) are the most frequent cause of fatal food allergic reactions. The allergenic 2S albumin Ara h 2 and the homologous minor allergen Ara h 6 were studied at the molecular level with regard to allergenic potency of native and protease-treated allergen. A high-resolution solution structure of the protease-resistant core of Ara h 6 was determined by NMR spectroscopy, and homology modelling was applied to generate an Ara h 2 structure. Ara h 2 appeared to be the more potent allergen, even though the two peanut allergens share substantial cross-reactivity. Both allergens contain cores that are highly resistant to proteolytic digestion and to temperatures of up to 100 degrees C. Even though IgE antibody-binding capacity was reduced by protease treatment, the mediator release from a functional equivalent of a mast cell or basophil, the humanized RBL (rat basophilic leukaemia) cell, demonstrated that this reduction in IgE antibody-binding capacity does not necessarily translate into reduced allergenic potency. Native Ara h 2 and Ara h 6 have virtually identical allergenic potency as compared with the allergens that were treated with digestive enzymes. The folds of the allergenic cores are virtually identical with each other and with the fold of the corresponding regions in the undigested proteins. The extreme immunological stability of the core structures of Ara h 2 and Ara h 6 provides an explanation for the persistence of the allergenic potency even after food processing.