Dissertations / Theses on the topic 'IgE mediated allergy'

Immunoglobulin E (IgE)-mediated allergy occurs when our immune system causes a reaction to otherwise harmless substances (allergens). Allergens are predominantly proteins present in biological materials such as pollens, mites, animal epithelia, moulds and foods.

In vitro tests for specific IgE antibodies usually employ an allergen source extract as an antibody capturing reagent. The proportion of allergenic molecules in these biochemically complex extracts may vary.

Recombinant allergens may be obtained in large quantities with biotechnological techniques. These proteins can be characterized biochemically and immunologically, resulting in tests with minimal batch-to-batch variation. This thesis describes different uses of recombinant allergens in component-resolved diagnostics (CRD).

In CRD, single allergenic proteins are used to establish a sensitization profile of the patient. Two timothy grass (Phleum pratense) pollen allergens, Phl p 11 and Phl p 4, were cloned and expressed as recombinant proteins. They were subsequently characterized and can, for example, be used in a panel for grass pollen CRD.

Single allergens may be useful as diagnostic markers for allergic sensitization. This phenomenon was studied using tropomyosin, a major allergen from the shrimp Penaeus aztecus (Pen a 1). The characteristics of the recombinant and natural proteins were compared. The recombinant tropomyosin was then extensively tested using specific competition for IgE binding against extracts of other crustacean species, house dust mite and cockroach.

In cases when an important allergen is missing or underrepresented in a natural extract, the corresponding recombinant allergen may be added to the extract as a spiking reagent. Previous studies have shown that latex extracts for diagnostic testing may lack the allergen Hev b 5. Recombinant Hev b 5 was expressed from a synthetic gene construct, incorporating several adaptations to enable efficient large scale production of the recombinant protein, to be used as a spiking reagent.

Allergic reactions are mainly mediated by the interactions between the IgE and its ligands, amongst them CD23 and CD21 in what is termed the IgE network. CD23 is involved in upregulating IgE expression by forming a trimolecular complex with CD21 and IgE on the B-cell surface, resulting in the specific activation of IgE-positive B cells. CD21 also interacts with C3d and is a bridge between the innate and the immune system. A crystal structure of the interaction has been solved (Szakonyi et al., 2001) but was controversial because it contradicted previous biochemical analyses. The aims of this thesis were to use various biophysical techniques to study the interactions between the molecules in the IgE network and its possible inhibition. Part 1: Characterisation of a phage display-derived peptide that inhibit IgE binding to CD23 A peptide was previously derived using phage display technology and tested for binding ability to CD23 using SPR and ITC. Subsequent NMR experiments were performed to identify the binding site, followed by characterization of its derivatives. Crystallisation of CD23 with the peptide and soaking with its truncated tripeptide, NWP, were also attempted. Part 2: Characterisation of CD23 and its interaction with its ligands X-ray crystallography was undertaken to solve the structure of derCD23 in complex with a phage display-derived peptide (Part1) followed by crystal soaking with a truncated tripeptide, NWP. However, a reproducible, high-resolution wild type derCD23 structure was determined at 1.9 Å. A comparison of the binding behaviour between the monomeric derCD23 and a trimeric CD23 construct was carried out in order to see the effect of oligomerisation upon IgE binding. Using the known interaction map as well as a crystal structure, the possible interacting residues between CD23 and IgE were examined. The characterisation of the CD23/CD21 interaction was continued from previous efforts in order to confirm that the binding epitope of CD23 for CD21 lies within the C-terminus of CD23. Characterisation of the interactions of CD23/IgE/FcεRI was performed to examine these multimolecular interactions and possible regulatory mechanisms in mast cell degranulation. It was shown that CD23 can form multimeric complexes with IgE-Fc that bind to FcεRI with higher apparent affinity than IgE-Fc alone, which may lead to increases in mast cell degranulation. It was also found that the IgE bound on FcεRI still binds to CD23 although with a lower binding capacity, presumably due allosteric changes. The binding of CD23 with a monoclonal antibody IDEC-152 was also characterised using SPR and NMR spectroscopy. It was proposed that IDEC-152 might interfere with the trimerisation site of CD23 thus reducing its affinity for IgE. A thermofluor assay was developed and optimised for potential screening of compounds that bind to derCD23 using a qPCR machine, which may be useful to screen compounds that bind to CD23 as part of future drug discovery project. Crystallisation of the derCD23/CD21 and IgE/triCD23/CD21 complexes was also attempted as part of ongoing crystallisation projects. Part 3: The interaction between C3d and CD21 The interaction between C3d and CD21 is believed to be a bridge between the innate and adaptive immune response, and is thought to be pivotal in the initiation of autoimmune disease. Following from previous studies on this interaction, further characterisations were performed using NMR and ITC to confirm the involved sites on CD21 (SCR1-2) in binding to C3d. Several potential salt bridges have been identified so far, allowing a high-resolution docked structure of the C3d/CD21 complex.

Includes bibliographical references.
Background: The prevalence of food allergy in South Africa is unknown, but previously thought to be low, particularly in black South Africans. We hypothesised that food allergies would be low in Xhosa patients, even those at increased risk of food allergy such as children with atopic dermatitis (AD). This study aimed to determine the prevalence of, patterns and risk factors for, IgE-mediated food allergy in South African children with moderate to severe AD. It is the first food allergy prevalence study in South Africa to utilise controlled food challenges and component analysis, and is unique for its comparison of food allergy patterns between ethnic groups in the same geographical area. Methodology: This was a prospective, observational study in a paediatric university hospital in Cape Town. Children with moderate to severe AD, aged 6 months to 10 years, were randomly recruited from the dermatology clinic. They were assessed for sensitisation and allergy by questionnaire, skin prick tests (SPT), Immuno Solid Phase Allergen Chip (ISAC) test and incremental food challenges. Sensitised patients were also tested for specific IgE by ImmunoCAP test. Results: One hundred participants (59 black Africans and 41 of mixed race) were enrolled, median age 42 months. There were high overall rates of food sensitisation (66%) and food allergy (40%). Egg (25%) and peanut (24%) were the most common allergies. Black participants had comparable sensitisation (69% vs 61%) but lower allergy rates (34% vs 46%) than mixed race participants. This was especially evident for peanut allergy (15% vs 37%, p=0.01). Early onset AD (< 6 months), severe eczema, and young age < 2 years were significant risk factors for food allergy. The ISAC test was less sensitive than SPT and ImmunoCAP tests. Only 42% of cases of perceived food allergy were confirmed as true food allergy.

Födoämnesallergi är en dold sjukdom som inte blir synlig förrän individen utvecklar en allergisk reaktion. Därifrån kan det snabbt handla om liv och död. Kroppens fysiska reaktion är väl utforskad och trots det, är hur sjukdomen påverkar patientens livssituation relativt outforskat. Omvårdnadslitteratur inom risker och åtgärder vid allergi nämner ytterst lite om födoämnesallergi. Studiens syfte var att beskriva patienters erfarenheter och uppfattningar av att leva med IgE-medierad födoämnesallergi. Genom en litteraturstudie framstod fyra teman: Rädsla och förlust av säkerhet, Att hantera vardagen, Betydelsen av information vad gäller märkning av livsmedel och Vikten av stöd från omgivningen. Upplevelsen av att inte ha kontroll, en ständig risk för oanade reaktioner, att inte alltid ha förståelse och behöva försvara sina behov, gav en negativ emotionell respons. Påverkan på livssituationen jämfört mellan lätt födoämnesallergi och svår födoämnesallergi var markant. Vägen tillbaka till en fungerande vardag bestod av strategier, förståelse, samt försoning. Ändå fanns hinder i omgivningen kvar. Kunskapen som genererades från studien är viktig för att sjuksköterskan ska kunna vårda en födoämnesallergisk patient utan att hindra läkande och känsla av säkerhet. Samhället behöver möta patientgruppens behov genom anpassning för att livskvalitet ska kunna uppnås.
Food allergy is a hidden disability that does not become visible until the individual develops an allergic reaction. From there on it can quickly become a matter of life or death. The physical response has been well researched and yet how the disease affects the patient’s life situation is relatively unexploded. Nursing literature regarding allergy risks and interventions mention little about food allergy. The aim of the study was therefore to highlight patients’ experiences and perceptions of living with IgE-mediated food allergy. Through a literature study four themes emerged: Fear and loss of security, Managing everyday life, Importance of information regarding labeling of food and The importance of support from others. The experience of not having control, a constant risk of unsuspected reactions, not always having an understanding from others and having to defend their needs gave a negative emotional response. The way back to an ordinary living consisted of strategies, understanding and reconciliation, yet there were still obstacles left in the environment. The knowledge of this study can be used in caring for a food allergic patient without jeopardizing healing process and feeling of security. The society needs to meet the patient group’s needs through adaptation, to achieve quality of life.

It is postulated that maternal n-3 (omega 3) long chain polyunsaturated fatty acids (LCPUFA) supplementation may modulate a range of inflammatory and immune pathways involved in the development of allergic diseases in early childhood, potentially leading to a reduction of allergic diseases in children. Thus the focus of this thesis was to determine whether maternal n-3 LCPUFA supplementation during pregnancy or lactation could prevent allergies in children. Two nested follow-up studies from two randomised controlled trials (RCTs) were performed, as well as a Cochrane systematic review to address this question. Of the two nested follow-up studies, one was a prenatal n-3 LCPUFA supplementation and the other a postnatal n-3 LCPUFA supplementation study. Parental reports of allergy outcomes were evaluated in children between birth to three years of age and birth to seven years of age in these studies. The Cochrane systematic review and meta-analysis was used to determine overall effects of maternal n-3 LCPUFA supplementation on allergy outcomes of the children involved. All relevant RCTs to date and the data from my two follow-up studies were included in the systematic review. Eight trials involving 3366 women and their 3175 children were included and in these trials, women were supplemented with n-3 LCPUFA during pregnancy (five trials), lactation (two trials) or both pregnancy and lactation (one trial). All trials randomly allocated women to either a n-3 LCPUFA supplement or a control group. The risk of bias varied across the eight included trials in this review with only two trials with a low risk of selection, performance and attrition bias. Overall, there is limited evidence to support maternal n-3 LCPUFA supplementation during pregnancy and/or lactation for reducing allergic disease in children. Few differences in childhood allergic disease were seen between women who were supplemented with n-3 LCPUFA and those who were not. N-3 LCPUFA supplementation showed a clear reduction in the primary outcome of any allergy (medically diagnosed IgE mediated) in children aged 12 to 36 months (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.44 to 0.98; two RCTs; 823 children), but not beyond 36 months (RR 0.86, 95% CI 0.61 to 1.20; one RCT, 706 children). For any allergy (medically diagnosed IgE mediated and/or parental report), no clear differences were seen in children either at 12 to 36 months (RR 0.89, 95% CI 0.71 to 1.11; two RCTs, 823 children) or beyond 36 months of age (RR 0.96, 95% CI 0.84 to 1.09; three RCTs, 1765 children). For the secondary outcomes of specific allergies there were no clear differences for food allergies at 12 to 36 months and beyond 36 months, but a clear reduction was seen for children in their first 12 months with n-3 LCPUFA (both for medically diagnosed IgE mediated and medically diagnosed IgE mediated and/or parental report). There was a clear reduction in medically diagnosed IgE mediated eczema with n-3 LCPUFA for children 12 to 36 months of age, but not at any other time point for both medically diagnosed IgE mediated and medically diagnosed IgE mediated and/or parental report. No clear differences for allergic rhinitis or asthma/wheeze were seen at any time point for both medically diagnosed IgE mediated, and medically diagnosed IgE mediated and/or parental report. There was a clear reduction in children's sensitisation to egg and sensitisation to at least one allergen between 12 to 36 months of age when mothers were supplemented with n-3 LCPUFA. In terms of safety for the mother and child, n-3 LCPUFA supplementation during pregnancy did not show increased risk of postpartum haemorrhage or early childhood infections. The data obtained in one of the nested follow-up studies in this thesis was used to compare the validity of parental reports of allergy outcome measures against medical diagnosis of allergies. This revealed that parental reports of doctor diagnosed eczema were the most reliable for the diagnosis of eczema in infants, but further studies are needed to validate other allergy outcomes before parent reports of allergy symptoms can be considered as a useful tool to evaluate early childhood allergies in large scale research.
Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2015.

碩士
國立臺灣海洋大學
食品科學系
93
Abstract Allergy owing to inappropriate immune responses to antigen in the environment. Asthma, allergic rhinitis and atopic dermatitis are common diseases which all belong to Type I allergic responses (so called IgE-mediated allergic responses). In recent study, it shows higher relationship between ROS and allergic responses. Curcumin is a major yellow pigment isolated from the spice turmeric. Dietary curcumin possesses an anti-oxidant and anti-inflammatory properties and it also exhibits significant chemopreventive activity. Rat basophilic leukemia cells (RBL -2H3) express α, β and γ chain of Fc�悐I, which plays a major role in the IgE-mediated allergic response. Antigen-IgE crosslinking initiates the release of ��-hexosaminidase, which is a marker of degranulation in RBL-2H3. Curcumin shows activity against ��- hexosaminidase release from IgE-mediated at 5 �嵱, even effective in calcium ionophores (A23187)-induced degranulation at��10 �嵱. Furthermore, effects of curcumin on antigen/A23187 induced release of histamine were also examined, both of them were decreased accompanied with the increasing concentration of curcumin. Among IgE-mediated allergic responses, antigen induces mast cells intracellular ROS production significantly. Curcumin could reduce ROS production from IgE-mediated or A23187 induced at 5 �嵱, and inhibits PKC-�� translocation from cytosolic to particulate. Fc�悐I consists of four subunits (������2), and the �� chain is high affinity to IgE. The surface expression of Fc�悐I in human basophilic cell line (KU812) also studied, treating with dose-dependent curcumin expresses lower level of mRNA expression of Fc�悐I ���nand ���nchain. Even 10 �嵱 curcumin could also suppress IL-4/IL-13 mRNA expression. And all above, these results suggest that curcumin can alleviate the IgE-mediate allergic responses through down-regulating Fc�悐I expression and reducing the production of the allergic mediates and ROS. Key words: Curcumin, IgE-mediated allergic responses, degranulation, ROS, PKC-���z Fc�悐I

碩士
國立臺灣海洋大學
食品科學系
95
Astaxanthin (AST), a non-pro-vitamin A carotenoid, is abundant in aquatic animals such as crab, shrimp etc. It possesses some pharmacological activities, including anti-inflammatory, anti-oxidative and immunomodulatory properties. IgE-mediated allergy owing to hyper-reactive immune responses to antigen in the environment. It shows high relationship beteewn reactive oxygen species (ROS) and allergic response through modulating intracellular signal transduction pathway. These actions cause the process of degranulation of mast cells resulting in the release of allergic mediators. In this report, we investigate the anti-allergic effect of AST and its possible mechanisms. The allergic model is established by RBL-2H3 and KU812 cells that sensitized by antigen and calcium ionophore (A23187). The results prove 100 uM AST inhibits 30 % of intracellular Ca+2 influx and almost abolished protein kinase C (PKC) phosphorylation and 40 % of ROS generation. Treating with 10-100 uM AST inhibits 20 % of histamine, b-hexosaminidase release. Expression the receptor for IgE (FceRI) is only inhibited by treating with high concentration (300 uM) AST. AST significantly reduce of IL-4 release at 100 uM and the IC50 for mitogen-activated protein kinases (MAPK) at 30 uM. And all above, these findings elucidate that astaxanthin can alleviate the IgE-mediate allergic response major by down-regulating ROS generation, reducing intracellular signaling pathways (Ca+2 influx, PKC and MAPK) and chemical mediators (histamine, b-hexosaminidase and IL-4) release. Key words: Astaxanthin, IgE-mediated allergic responses, mast cell, degranulation, basophil

Allergic asthma is characterized by airway hyperresponsiveness, inflammation, and a cellular infiltrate dominated by eosinophils. Numerous epidemiological studies have related the exacerbation of allergic asthma with an increase in ambient inhalable particulate matter from air pollutants. This is because inhalable particles efficiently deliver airborne allergens deep into the airways, where they can aggravate allergic asthma symptoms. However, the cellular mechanisms by which inhalable particulate allergens (pAgs) potentiate asthmatic symptoms remain unknown, in part because most in vivo and in vitro studies exploring the pathogenesis of allergic asthma use soluble allergens (sAgs). Using a mouse model of allergic asthma, we found that, compared with their sAg counterparts, pAgs triggered markedly heightened airway hyperresponsiveness and pulmonary eosinophilia in allergen-sensitized mice. Mast cells (MCs) were implicated in this divergent response, as the differences in airway inflammatory responses provoked by the physical nature of the allergens were attenuated in MC-deficient mice. The pAgs were found to mediate MC-dependent responses by enhancing retention of pAg/IgE/FcεRI complexes within lipid raft–enriched, CD63(+) endocytic compartments, which prolonged IgE/FcεRI-initiated signaling and resulted in heightened cytokine responses. These results reveal how the physical attributes of allergens can co-opt MC endocytic circuitry and signaling responses to aggravate pathological responses of allergic asthma in mice.
Dissertation

碩士
南臺科技大學
生物科技系
106
In recent years, the deterioration of air and the environment has led to moreallergic patients, e.g. allergic rhinitis, asthma and contact dermatitis etc.Recently many studies indicate that the active compounds and pharmacological of C. militaris is even higher and better than that of C. sinensis so that C. sinensis is gradually taken place by C. militaris. Besides, many researchers also apply C. militaris to alleviate the symptoms of various diseases. The results of this study indicated that ethanol extract from silkworm pupa-cultivated C. militaris fruit bodies (CM_EE) could inhibit symptoms of IgE-mediated allergic rhinitis in BALB/c mice. Therefore, we investigated more about the inhibition molecular mechanisms of CM_EE. CM_EE treatment showed the ability to inhibit degranulation in the dose-dependent way. Additionally, CM_EE incubation decreased intracellular calcium influx. Further western immunoblotting results demonstrated that CM_EE incubation could interfere with the activation of Bruton Tyrosine Kinase、Protein Kinase C、p38 mitogen activated protein kinase and 14-3-3γ while promoted the phosphorylation of Eukaryotic translation initiation factor 2 subunit 1 and Peroxisome proliferator-activated receptor γ protein expression. The above results implicated that CM_EE treatment could regulate FcεRI signaling pathway, intracellular calcium level and degranulation to decrease cytokine secretion and thus alleviate allergic rhinitis. In conclusion, CM_EE might be a potential Chinese herbal drug for curing allergy.