Induction and measurement of IgE : a study in mice, with emphasis on the regulatory role of lymphokines

A better understanding of the regulatory mechanisms and cellular interactions of the IgE antibody response is of fundamental interest to allergologists and clinical immunologists because of the role of IgE in the pathogenesis of the immediate type allergic disease. In addition, basic knowledge of the regulation of IgE antibody formation may lead to new forms of treatment including suppression of excessively formed IgE antibody. Beyond the clinical significance, the IgE antibody response provides an excellent model to establish the interdependencies and regulatory events governing the expression of different isotypes at different levels. The formation of IgE antibodies is regulated by T cells and controlled by antigen- and/or isotype-specific interactions. Thus, external modulation of IgE production can be achieved by antigen, idiotype and anti-idiotype, being specific recognition elements in the establishment and control of an immune response. Also IgE specific regulatory factors and receptors on different types of cells exert a regulatory influence. In the case of isotype-specific regulation, total IgE antibody may be affected irrespective of its specificity. This is of relevance for eventual treatment of generalized IgE mediated allergic diseases. On the other hand, an antigen-specific modulation of an immune response will also affect the expression of other isotypes, even in a secondary response. From the above it is clear that much of the knowledge on the induction of the allergic inflammation gained from animal studies is clinically relevant. Moreover, the basic mechanisms of IgE regulation seem to be similar in man and in mice and rats. This is the underlying premise for these studies. The purpose of the investigations presented in this thesis was to get more insight into the mechanisms underlying the induction of IgE antibody formation in the mouse and the regulation of this IgE synthesis. For this study the development of suitable reagents and appropriate assay systems was indicated. Only since the availability of antigen-specific mouse IgE-secreting hybridomas, it became feasible to isolate enough IgE for the induction of heterologous anti-IgE antisera. This purified IgE can also be used as a reference standard in the quantitative determination of IgE. Furthermore, the hybridoma cells can be employed for the standardization of techniques that allow the determination of IgE-secreting cells. It is therefore that in Chapter 4 we focuss on the isolation and purification of monoclonal murine IgE, the generation of heterologous IgE-specific antisera and the development of a Terasaki-ELISA system for the quantitative determination of secreted IgE. Employing one of these an

Is ADHD een (niet-)allergische overgevoeligheid? Een hypothese

Onderzoeksresultaten naar het causale verband tussen ‘Attention-deficit hyperactivity disorder’ (ADHD) en allergieën zijn niet eenduidig. Allergieën zoals astma en eczeem zijn klinische syndromen waarbij zowel genetische aanleg als omgevingsfactoren (huisdieren, huisstofmijten, pollen en voeding) kunnen bijdragen tot de ontwikkeling ervan. De hypothese dat ADHD bij sommige kinderen ook een allergie kan zijn, wordt onderbouwd aan de hand van de verschillende mechanismen die ten grondslag liggen aan zowel ADHD als allergische aandoeningen. Volgens de geaccepteerde terminologie voor allergie voldoet ADHD aan de criteria van overgevoeligheid, allergie en atopie. Deze hypothese zal in gerandomiseerd gecontroleerd onderzoek getoetst moeten worden. Hierbij moet niet alleen gebruik gemaakt worden van immunologisch onderzoek, maar ook van genetisch onderzoek. Dit omdat genen die gerelateerd worden aan het immuunsysteem met ADHD geassocieerd kunnen worden. Immunotherapeutische benaderingen, zoals immunotherapie en probiotica, zouden betrokken kunnen worden bij de behandeling van ADHD. Wanneer overgevoeligheid voor omgevingsfactoren, zoals voedingsmiddelen, bijdraagt aan het manifest worden van ADHD, zal de diagnostiek en de behandeling van ADHD herzien moeten worden, om zo de kwaliteit van zorg voor deze patiënten te verbeteren

Semi-preparative purification and validation of monoclonal antibodies for immunotherapy in mice

A number of rat hybridomas were adapted to grow in RPMI containing either 5% IgG-depleted FCS of 1% serum-free Nutridoma. Alternatively, protein-free Ultradoma PF was used. Growth in these media allowed purification procedures to be used that are based on tangential ultrafiltration in combination with affinity chromatography on gels linked to protein G or anti-rat L chain coupled antibodies. The isolated antibody preparations were found to be pure and to consist of monomeric intact IgG. The yield and recovery of mAb using this procedure were found to be consistently high. These antibody preparations were analyzed for endotoxin contamination. Whereas during isolation endotoxin contamination increased, the endotoxin content per mg purified protein did not. Affinity chromatography on Detoxi-gel resulted in the efficient removal of this contamination and using this protocol the antibody preparations obtained were found to be of sufficient purity, activity and low endotoxin content to permit their in vivo use in animal models of immunotherapy

Antiinflammatory and immunomodulating properties of fungal metabolites

We discuss current information on the ability of extracts and isolated metabolites from mushrooms to modulate immune responses. This can result in a more enhanced innate and acquired disease resistance. The major immunomodulating effects of these active substances derived from mushrooms include mitogenicity and activation of immune effector cells, such as lymphocytes, macrophages, and natural killer cells, resulting in the production of cytokines, including interleukins (ILs), tumor necrosis factor alpha (TNF)-¿, and interferon gamma (INF)-¿. In particular, the ability of selective mushroom extracts to modulate the differentiation capacity of CD4+ T cells to mature into TH1 and/or TH2 subsets will be discussed. As a consequence these extracts will have profound effects in particular diseases, like chronic autoimmune TH1-mediated or allergic TH2-mediated diseases. Immunosuppressive effects by mushroom components have also been observed. The therapeutic effects of mushrooms, such as anticancer activity, suppression of autoimmune diseases, and allergy have been associated with their immunomodulating effects. However, further studies are needed to determine the molecular mechanisms of the immunomodulating effects of mushrooms metabolites both individually and in complex mixtures, for example, extract

Effects of organically and conventionally produced feed on biomarkers of health in a chicken model

Consumers expect organic products to be healthier. However, limited research has been performed to study the effect of organic food on health. The present study aimed to identify biomarkers of health to enable future studies in human subjects. A feeding experiment was performed in two generations of three groups of chickens differing in immune responsiveness, which were fed identically composed feeds from either organic or conventional produce. The animals of the second generation were exposed to an immune challenge and sacrificed at 13 weeks of age. Feed and ingredients were analysed on macro- and micronutrients, i.e. vitamins, minerals, trace elements, heavy metals and microbes. The chickens were studied by general health and immune parameters, metabolomics, genomics and post-mortem evaluation. The organic and conventional feeds were comparable with respect to metabolisable energy. On average, the conventionally produced feeds had a 10 % higher protein content and some differences in micronutrients were observed. Although animals on both feeds were healthy, differences between the groups were found. The random control group of chickens fed conventional feed showed overall a higher weight gain during life span than the group on organic feed, although feed intake was mostly comparable. The animals on organic feed showed an enhanced immune reactivity, a stronger reaction to the immune challenge as well as a slightly stronger ‘catch-up growth’ after the challenge. Biomarkers for future research were identified in the parameters feed intake, body weight and growth rate, and in immunological, physiological and metabolic parameters, several of these differing most pronounced after the challeng

Polymorphism of major histocompatibility complex class II B genes in different carp lines of the common carp (Cyprinus carpio L.)

Regular observation of survival of the carp breeding lines constituting a living gene bank at the Institute of Ichthyobiology and Aquaculture in Golysz (Poland) over a period of at least 15 years showed different survival rates for various lines. In this study, we have examined the polymorphism of the major histocompatibility complex (MHC) gene class II B in nine carp lines. The class II B gene encodes for the part of the MHC class II molecule which presents peptides from pathogens and protein antigens that are present in the extracellular milieu and have been taken up into the endocytic vesicles of antigen-presenting cells. Polymerase chain reaction was used to amplify Cyca-DAB gene fragments comprising part of exon 1, complete intron 1 and almost complete exon 2. Exon 2 encodes for the beta(1) domain which is the most polymorphic fragment of MHC class II molecules. Single-strand conformational polymorphism (SSCP) was applied to detect different MHC class II B haplotypes. The analysis revealed the presence of seven different haplotypes occurring with various frequencies. (C) 2003 Editions scientifiques et medicales Elsevier SAS and Ifremer/IRD/Inra/Cemagref. All rights reserved

Modulation of systemic cytokine levels by implantation of alginate encapsulated cells

The availability of cell lines that are transfected with IL-4, IL-5 and IFN-γ cytokine genes permits the prolonged in vivo delivery of functional cytokines in relatively large doses for the modulation of specific immune responses. Oft

Involvement of T cells in enhanced resistance to Klebsiella pneumoniae septicemia in mice treated with liposome-encapsulated muramyl tripeptide phosphatidylethanolamine or gamma interferon

We have previously shown that prophylactic administration of the liposome-encapsulated immunomodulating agents muramyl tripeptide phosphatidylethanolamine (MTPPE) and gamma interferon (IFN-gamma) results in strongly increased survival of mice from a normally lethal septicemia with Klebsiella pneumoniae. It was anticipated that the treatment acts on macrophages and nonspecifically augments host resistance to various infections. In the present study, we provide evidence for a key role for T cells in host defense potentiation by the liposomal immunomodulators toward K. pneumoniae septicemia. It is shown that both CD4 and CD8 cells are important in immunomodulation, most likely due to production of IFN-gamma. Depletion of circulating IFN-gamma resulted in strong reduction of the antimicrobial host defense activation. Administration of interleukin-10 resulted in decreased antimicrobial host defense activation by liposomal immunomodulators. Moreover, administration of liposomal immunomodulators was shown to induce predominantly T-helper type 1 (Th1) cell populations in the spleen. These findings indicate that immunomodulation with liposomal MTPPE and IFN-gamma favors Th1 and NK cell activation

Major histocompatibility genes in the Lake Tana African large barb species flock: evidence for complete partitioning of class II B, but nog class I, genes among different species

The 16 African large barb fish species of Lake Tana inhabit different ecological niches, exploit different food webs and have different temporal and spatial spawning patterns within the lake. This unique fish species flock is thought to be the result of adaptive radiation within the past 5 million years. Previous analyses of major histocompatibility class II B exon 2 sequences in four Lake Tana African large barb species revealed that these sequences are indeed under selection. No sharing of class II B alleles was observed among the four Lake Tana African large barb species. In this study we analysed the class II B exon 2 sequences of seven additional Lake Tana African large barb species and African large barbs from the Blue Nile and its tributaries. In addition, the presence and variability of major histocompatibility complex class I UA exon 3 sequences in six Lake Tana and Blue Nile African large barb species was analysed. Phylogenetic lineages are maintained by purifying or neutral selection on non-peptide binding regions. Class II B intron 1 and exon 2 sequences were not shared among the different Lake Tana African large barb species or with the riverine barb species. In contrast, identical class I UA exon 3 sequences were found both in the lacustrine and riverine barb species. Our analyses demonstrate complete partitioning of class II B alleles among Lake Tana African large barb species. In contrast, class I alleles remain for the large part shared among species. These different modes of evolution probably reflect the unlinked nature of major histocompatibility genes in teleost fishes