Allergen mimotopes

The causative treatment of type I allergies is a long pursued goal in immunology. To design safe and efficient vaccine preparations, the interaction of the allergen and the symptom-inducing IgE antibodies still needs to be better understood. In this article, we describe the use of the phage display technique in allergy. It yields epitope mimics, so-called mimotopes, which can be employed for both, investigation of allergen-IgE interactions and definition of safe novel vaccines.     

A Protein Allergen Microarray Detects Specific IgE to Pollen Surface,Cytoplasmic, and Commercial Allergen Extracts

Background

Current diagnostics for allergies, such as skin prick and radioallergosorbent tests, do not allow for inexpensive, high-throughput screening of patients. Additionally, extracts used in these methods are made from washed pollen that lacks pollen surface materials that may contain allergens.

Methodology/Principal Findings

We sought to develop a high-throughput assay to rapidly measure allergen-specific IgE in sera and to explore the relative allergenicity of different pollen fractions (i.e. surface, cytoplasmic, commercial extracts). To do this, we generated a protein microarray containing surface, cytoplasmic, and commercial extracts from 22 pollen species, commercial extracts from nine non-pollen allergens, and five recombinant allergenic proteins. Pollen surface and cytoplasmic fractions were prepared by extraction into organic solvents and aqueous buffers, respectively. Arrays were incubated with <25 uL of serum from 176 individuals and bound IgE was detected by indirect immunofluorescence, providing a high-throughput measurement of IgE. We demonstrated that the allergen microarray is a reproducible method to measure allergen-specific IgE in small amounts of sera. Using this tool, we demonstrated that specific IgE clusters according to the phylogeny of the allergen source. We also showed that the pollen surface, which has been largely overlooked in the past, contained potent allergens. Although, as a class, cytoplasmic fractions obtained by our pulverization/precipitation method were comparable to commercial extracts, many individual allergens showed significant differences.

Conclusions/Significance

These results support the hypothesis that protein microarray technology is a useful tool for both research and in the clinic. It could provide a more efficient and less painful alternative to traditionally used skin prick tests, making it economically feasible to compare allergen sensitivity of different populations, monitor individual responses over time, and facilitate genetic studies on pollen allergy.     

Studies on Allergen of Fasciola hepatica

Allergenic substance obtained from liver flukes, P4, is composed of ribonucleic acid and peptide, but it was negative in ninhydrin reaction. The preparation was dinitrophenylated without any loss of its biological activity. When the dinitrophenylated material was subjected to digestion by ribonuclease and other enzymes, adenosine-3′-phosphate combined with DNP-peptide was obtained. The DNP-peptide, after hydrolysed with dilute alkali, produced a peptide whose amino terminal was histidine.     

Studies on Allergen of Fasciola hepatica

Two allergenic substances (C 5 and P 4), which consisted of ribonucleic acid as their main component, were isolated from the heated extract of liver fluke (Fasciola hepatica) by means of precipitation by ammonium sulphate and phenol extraction, followed by extraction with potassium acetate and ethanol fractionation.

One of these substances, C 5, which was extracted with phenol was electrophoretically homogeneous, but ultracentrifugally was shown to contain one other substance in a small quantity.

The other substance, P 4, which was isolated from the phenol insoluble fraction was electrophoretically and ultracentrifugally homogeneous.

Both of these were almost the same in biological activity, and their solutions, which were diluted 1 : 100,000 with Ringer’s solution, were still active in the intradermal reaction to the fascioliasis of cattle. Judging from their activity and yield, it seems that all the allergenic substances which are in the heated extract of liver fluke, are represented by the protein allergen reported already, as well as by C 5 and P 4 described here.     

Perinatal taurine exposure affects adult arterial pressure control

Taurine is an abundant, free amino acid found in mammalian cells that contributes to many physiologic functions from that of a simple cell osmolyte to a programmer of adult health and disease. Taurine’s contribution extends from conception throughout life, but its most critical exposure period is during perinatal life. In adults, taurine supplementation prevents or alleviates cardiovascular disease and related complications. In contrast, low taurine consumption coincides with increased risk of cardiovascular disease, obesity and type II diabetes. This review focuses on the effects that altered perinatal taurine exposure has on long-term mechanisms that control adult arterial blood pressure and could thereby contribute to arterial hypertension through its ability to program these cardiovascular regulatory mechanisms very early in life. The modifications of these mechanisms can last a lifetime and transfer to the next generation, suggesting that epigenetic mechanisms underlie the changes. The ability of perinatal taurine exposure to influence arterial pressure control mechanisms and hypertension in adult life appears to involve the regulation of growth and development, the central and autonomic nervous system, the renin–angiotensin system, glucose–insulin interaction and changes to heart, blood vessels and kidney function.     

用于变应原疫苗分析和质控的实验技术

建立和应用一种可靠的质量分析方法是所有生物制品质量和工艺一致性的保障。一种准确反应药物中特异组成成分的活性和结构,并且优化和验证了的方法,是所有生物医药领域研发和新药上市的一个核心目标。变应原疫苗是天然物质的混合物,每一种变应原疫苗含有多种活性成分和与变应原无关未知的非活性成分,其中,具有变应原活性的物质只占一小部分,而且主要变应原成分作用在患者与患者之间差异性很大。本文介绍了一种变应原疫苗分析和质控的方法,包括变应原疫苗总蛋白含量、总蛋白组分、主要致敏蛋白组成、主要致敏蛋白含量、总生物活性几方面。     

Circadian Variation in Allergen and Nonspecific Bronchial Responsiveness in Asthma

In a majority of patients, exacerbations of asthma occur more frequently during the night than day. Many hypotheses have been proposed to explain such variation in asthma. The airways of asthmatic persons are characterized by an abnormal degree of inflammation and bronchial hyperre-sponsiveness to both nonspecific and specific challenges. Studies of both children and adults with asthma document marked circadian rhythmicity in the response of airways to bronchial challenges with histamine, methacho-line, acetylcholine, saline, and house dust mite. Taken together, the findings of these investigations indicate that the hyperreactivity of airways to these agents is more profound and prolonged following evening and overnight tests compared to tests conducted in the midday and afternoon. The temporal pattern in bronchial response to the hyperventilation of cold dry air is different. The hyperresponsiveness of airways to this challenge is greatest in the afternoon. The amplitude of the circadian rhythm in airway hyperreactivity seems to be correlated to the amplitude of the circadian rhythm of pulmonary function; the greater the day-night difference in bronchial reactivity is, the greater is the day-night difference in flow rates.     

Clinical and Laboratory Studies of the Fate of Intranasal Allergen

BackgroundThe precise way in which allergen is handled by the nose is unknown. The objective of this study was to determine recovery of Der p 1 allergen following nasal administration and to determine whether Der p 1 can be detected in nasal biopsies after natural exposure and nasal challenge to allergen.Methods(1) 20 nonatopic non-rhinitics were challenged with Der p 1 and recovery was measured by ELISA in the nasal wash, nasal mucus and induced sputum up to 30 minutes. Particulate charcoal (<40 μm) served as control. (2) In 8 subjects (5 atopics), 30 to 60 minutes after challenge histological localisation of Der p 1 in the nasal mucosal epithelium, subepithelial mucous glands and lamina propria was performed. Co-localisation of Der p 1 with macrophages and IgE-positive cells was undertaken.Results(1) Less than 25% of total allergen was retrievable after aqueous or particulate challenge, most from the nasal mucus during 1-5 min after the challenge. The median of carbon particles recovered was 9%. (2) Prechallenge Der p 1 staining was associated with the epithelium and subepithelial mucous glands. After challenge there was a trend for greater Der p 1 deposition in atopics, but both atopics and nonatopics showed increases in the number of Der p 1 stained cells and stained tissue compartments. In atopics, increased eosinophils, macrophages and IgE positive cells co-localized with Der p 1 staining.ConclusionsDer p 1 allergen is detected in nasal tissue independent of atopic status after natural exposure. After challenge the nose effectively retains allergen, which remains mucosally associated; in atopics there is greater Der p 1 deposition and inflammatory response than in nonatopics. These results support the hypothesis that nasal mucus and tissue act as a reservoir for the inhaled Der p 1 allergen leading to a persistent allergic inflammatory response in susceptible individuals.     

Structural and Dynamic Properties of Allergen and Non-Allergen Forms of Tropomyosin

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美洲大蠊变应原Pera2的生物信息学分析

目的:了解美洲大蠊变应原Per a 2的分子生物学特征。方法:从Genbank中获得Per a 2的核酸序列,用ExPaSy、EBI和NCBI网站的在线软件推导出编码氨基酸序列及其理化性质、空间结构、功能位点,并在Blastp比对后选择不同物种同源序列计算相似率、构建分子进化树。结果:Pera2由351个氨基酸细戍,分子量为38119Da、等电点为4.90、分子式为C1217H1825N285O297S18,为细胞外疏水性蛋白、属于肽酶a家族,信号肽位于1～20氨基酸处,三个跨膜螺旋区域依次位于1～19aa、51～78aa、282～300aa处;二级结构由α-螺旋(9.4%)、β延伸(28.49%)、随机线圈(62.11%)组成;美洲大蠊和德国小蠊相似率为55%、与马德拉蜚蠊相似率为51%,三者在Pera2与不同物种的同源序列构建的分子进化树中聚成一簇。结论:通过对Per a 2的生物信息学分析获得了该变应原分子特征,为进一步研究奠定基础。     

Disease-linked mutations cause exposure of a protein quality control degron

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In situ exposure to non-directional beacons for air traffic control

In situ electromagnetic field exposure of workers and the general public due to non-directional beacons (NDB) for air traffic control is assessed and characterized. For occupational exposure, the maximal measured electric field value is 881.6 V/m and the maximal magnetic field value is 9.1 A/m. The maximum electric fields exceed the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels at all seven NDB sites, and the magnetic fields at two of the seven NDB sites (occupational exposure). Recommendations and compliance distances for workers and the general public are provided.     

Characterising CT automatic exposure control systems using a CeLT phantom

Introduction: CT automatic exposure control (AEC) systems have significant impact on patient dosimetry in modern CT systems. However a reliable method for assessment of AEC systems has not been established as part of quality assurance protocols.Methods: Six systems were assessed from three different vendors (1 GE, 4 Siemens, 1 Philips) using the CeLT phantom. The CeLT phantom (Medical Physics, BCUHB, Wales) consists of four water filled elliptical sections of varying diameters with four CT     

Crystal Structure of the Dog Lipocalin Allergen Can f 2: Implications for Cross-reactivity to the Cat Allergen Fel d 4

The dog lipocalin allergen Can f 2 is an important cause of allergic sensitization in humans worldwide. Here, the first crystal structure of recombinant rCan f 2 at 1.45 Å resolution displays a classical lipocalin fold with a conserved Gly-Xaa-Trp motif, in which Trp19 stabilizes the overall topology of the monomeric rCan f 2. Phe38 and Tyr84 localized on the L1 and L5 loops, respectively, control access to the highly hydrophobic calyx. Although the rCan f 2 calyx is nearly identical with the aero-allergens MUP1, Equ c 1 and A2U from mouse, horse and rat, respectively, no IgE cross-reactivity was found using sera from five mono-sensitized subjects. However, clear IgE cross-reactivity was demonstrated between Can f 2 and the cat allergen Fel d 4, although they share less than 22% sequence identity. This suggests a role for these allergens in co-sensitization between cat- and dog-allergic patients.     

Purification and Recombinant Expression of Major Peanut Allergen Ara h 1

Reaction to peanut, as one of the major food allergens, has become an increasingly common life-threatening disorder. Although peanut allergens have been extensively identified, Ara h 1 is still too expensive to be applied in food safety or clinical utility. In this study, the purification, expression, and immunological analyses of Ara h 1 are investigated. It was shown that a high purity (>95%) of Ara h 1 could be prepared by either purification or expression. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Western blot, and mass spectroscopy were used to identify the Ara h 1, and it was found that natural Ara h 1 (nAra h 1) and expressed Ara h 1 (rAra h 1) have the same properties, including amino acid sequence. In particular, rAra h 1 reacted positively with anti-nAra h 1 serum, showing their similar immunological property. Thus, by either purification or expression, Ara h 1 could be prepared with low cost, as performed in the present work. SDS-PAGE, mag trix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS), and immunological analysis confirmed that both forms of Ara h 1 had the same properties.