The Journal of Visualized Experiments (JoVE) is a peer reviewed, PubMed-indexed video journal. Our mission is to increase the productivity of scientific research.

Recommend to Librarian

In JoVE (1)

Other Publications (23)

Automatic Translation

This translation into Swedish was automatically generated.
English Version | Other Languages

Articles by Martin Himly in JoVE

 JoVE Immunology and Infection

Basophil Aktivering test för utredning av IgE-medierade mekanismer i Läkemedelsöverkänslighet


JoVE 3263 9/16/2011

1Department of Molecular Biology, University of Salzburg, 2Department of Neurology, Paracelsus Medical University, 3Department of Dermatology, Paracelsus Medical University, 4Bühlmann Laboratories, 5Christian Doppler Laboratory for Allergy Diagnosis and Therapy, University of Salzburg

Basophil aktivering test är ett kraftfullt verktyg för detektering av IgE-beroende allergier

Other articles by Martin Himly on PubMed

The T Cell Response to Art V 1, the Major Mugwort Pollen Allergen, is Dominated by One Epitope

Mugwort (Artemisia vulgaris) pollen allergens represent the main cause of pollinosis in late summer in Europe. At least 95% of sera from mugwort pollen-allergic patients contain IgE against a highly glycosylated 24- to 28-kDa glycoprotein. Recently, this major allergen, termed Art v 1, was characterized, cloned in Escherichia coli, and produced in recombinant form. In the present study we characterized and compared the T cell responses to natural (nArt v 1) and recombinant Art v 1 (rArt v 1). In vitro T cell responses to nArt v 1 and rArt v 1 were studied in PBMC, T cell lines (TCL), and T cell clones (TCC) established from PBMC of mugwort-allergic patients. Stimulation of PBMC or allergen-specific TCL with either nArt v 1 or rArt v 1 resulted in comparable proliferative T cell responses. Eighty-five percent of the TCC reactive with rArt v 1 cross-reacted with the natural protein. The majority of the CD4(+)CD8(-)TCR alphabeta(+) Art v 1-specific TCC, obtained from 10 different donors, belonged to the Th2 phenotype. Epitope mapping of TCL and TCC using overlapping peptides revealed a single immunodominant T cell epitope recognized by 81% of the patients. Inhibition experiments demonstrated that the presentation of this peptide is restricted by HLA-DR molecules. In conclusion, the T cell response to Art v 1 is characterized by one strong immunodominant epitope and evidently differs from the T cell responses to other common pollen allergens known to contain multiple T cell epitopes. Therefore, mugwort allergy may be an ideal candidate for a peptide-based immunotherapy approach.

Art V 1, the Major Allergen of Mugwort Pollen, is a Modular Glycoprotein with a Defensin-like and a Hydroxyproline-rich Domain

In late summer, pollen grains originating from Compositae weeds (e.g., mugwort, ragweed) are a major source of allergens worldwide. Here, we report the isolation of a cDNA clone coding for Art v 1, the major allergen of mugwort pollen. Sequence analysis showed that Art v 1 is a secreted allergen with an N-terminal cysteine-rich domain homologous to plant defensins and a C-terminal proline-rich region containing several (Ser/Ala)(Pro)2-4 repeats. Structural analysis showed that some of the proline residues in the C-terminal domain of Art v 1 are posttranslationally modified by hydroxylation and O-glycosylation. The O-glycans are composed of 3 galactoses and 9-16 arabinoses linked to a hydroxyproline and represent a new type of plant O-glycan. A 3-D structural model of Art v 1 was generated showing a characteristic "head and tail" structure. Evaluation of the antibody binding properties of natural and recombinant Art v 1 produced in Escherichia coli revealed the involvement of the defensin fold and posttranslational modifications in the formation of epitopes recognized by IgE antibodies from allergic patients. However, posttranslational modifications did not influence T-cell recognition. Thus, recombinant nonglycosylated Art v 1 is a good starting template for engineering hypoallergenic vaccines for weed-pollen therapy.

IgE-mediated Immediate-type Hypersensitivity to the Pyrazolone Drug Propyphenazone

Propyphenazone (1,2-dihydro-1,5-dimethyl-4-(1-methylethyl)-2-phenyl-3H-pyrazol-3-one; PP) is a nonsteroidal anti-inflammatory drug frequently used as mild analgesic medicament. It belongs to the chemical group of pyrazolones. Severe adverse reactions to PP are frequent and have generally been regarded as pseudoallergic or intolerance reactions. Presently, there are no useful in vitro test systems available for the detection of antibodies directed against analgesic drugs.

Native Art V 1 and Recombinant Art V 1 Are Able to Induce Humoral and T Cell-mediated in Vitro and in Vivo Responses in Mugwort Allergy

Mugwort pollen is an important allergen source in hay fever and pollen-related food allergy. Little is known about the clinical relevance of the major mugwort allergen Art v 1 and its importance in allergy.

Biology of Weed Pollen Allergens

Weeds represent a heterogeneous group of plants, usually defined by no commercial or aesthetic value. Important allergenic weeds belong to the plant families Asteraceae, Amaranthaceae, Urticaceae, Euphorbiaceae, and Plantaginaceae. Major allergens from ragweed, mugwort, feverfew, pellitory, goosefoot, Russian thistle, plantain, and Mercurialis pollen have been characterized to varying degrees. Four major families of proteins seem to be the major cause of allergic reactions to weed pollen: the ragweed Amb a 1 family of pectate lyases; the defensin-like Art v 1 family from mugwort, feverfew, and probably also from sunflower; the Ole e 1-like allergens Pla l 1 from plantain and Che a 1 from goosefoot; and the nonspecific lipid transfer proteins Par j 1 and Par j 2 from pellitory. As described for other pollens, weed pollen also contains the panallergens profilin and calcium-binding proteins, which are responsible for extensive cross-reactivity among pollen-sensitized patients.

Two Novel Types of O-glycans on the Mugwort Pollen Allergen Art V 1 and Their Role in Antibody Binding

Art v 1, the major allergen of mugwort (Artemisia vulgaris) pollen contains galactose and arabinose. As the sera of some allergic patients react with natural but not with recombinant Art v 1 produced in bacteria, the glycosylation of Art v 1 may play a role in IgE binding and human allergic reactions. Chemical and enzymatic degradation, mass spectrometry, and 800 MHz (1)H and (13)C nuclear magnetic resonance spectroscopy indicated the proline-rich domain to be glycosylated in two ways. We found a large hydroxyproline-linked arabinogalactan composed of a short beta1,6-galactan core, which is substituted by a variable number (5-28) of alpha-arabinofuranose residues, which form branched side chains with 5-, 2,5-, 3,5-, and 2,3,5-substituted arabinoses. Thus, the design of the Art v 1 polysaccharide differs from that of the well known type II arabinogalactans, and we suggest it be named type III arabinogalactan. The other type of glycosylation was formed by single (but adjacent) beta-arabinofuranoses linked to hydroxyproline. In contrast to the arabinosylation of Ser-Hyp(4) motifs in other hydroxyproline-rich glycoproteins, such as extensins or solanaceous lectins, no oligo-arabinosides were found in Art v 1. Art v 1 and parts thereof produced by alkaline degradation, chemical deglycosylation, proteolytic degradation, and/or digestion with alpha-arabinofuranosidase were used in enzyme-linked immunosorbent assay and immunoblot experiments with rabbit serum and with the sera of patients. Although we could not observe antibody binding by the polysaccharide, the single hydroxyproline-linked beta-arabinose residues appeared to react with the antibodies. Mono-beta-arabinosylated hydroxyproline residues thus constitute a new, potentially cross-reactive, carbohydrate determinant in plant proteins.

Production and Characterization of an Allergen Panel for Component-resolved Diagnosis of Celery Allergy

In celery a relevant food allergen source, three allergens have been identified so far: Api g 1 and Api g 4, and one glycosylated protein, Api g 5. For component-resolved food allergy diagnosis high amounts of well-defined allergens are needed. Depending on the individual celery allergen, protocols for heterologous production and purification from natural source, respectively, were established to obtain homogenous protein batches. Afterwards the purified recombinant allergens, Api g 1, Api g 4 and natural Api g 5 were characterized regarding their structural integrity and immunological activity. Therefore, several methods were applied. Proteins were identified by partial N-terminal sequencing, protein mass was verified by MS and sequence integrity by MALDI-TOF and N-terminal sequencing after tryptic digestion. Presence of isoforms in natural allergen preparations was identified by 2-DE. Secondary and tertiary structures were evaluated by circular dichroism (CD) spectroscopy and NMR analysis. Finally, IgE binding capacity was verified using selected sera from celery allergic patients in IgE immunoblots and IgE ELISA. These well-defined celery allergens will be used to prove the concept of component-resolved diagnosis and will contribute to improve food allergy diagnosis in the future.

Comparison of Natural and Recombinant Forms of the Major Fish Allergen Parvalbumin from Cod and Carp

Allergic reaction following fish consumption can trigger life-threatening reactions in predisposed individuals. Parvalbumins from different species have been identified as the major fish allergens. There are two distinct phylogenetic lineages of parvalbumins, alpha and beta. Most allergic reactions are caused by beta-parvalbumins. We cloned and expressed cDNAs encoding cod (Gadus morhua) and carp (Cyprinus carpio) beta-parvalbumins and purified natural cod beta-parvalbumin. CD spectra of the purified proteins showed that their overall secondary structure contents were very similar. No differences in thermal stability were monitored in the calcium-bound or calcium-depleted form of natural cod parvalbumin. IgE reactivity was assessed using 26 sera of fish allergic patients from Spain, The Netherlands, and Greece in immunoblot and ELISA experiments. Twenty-five of the 26 patients with IgE reactivity to native and recombinant cod parvalbumin also reacted to the recombinant carp parvalbumin. IgE inhibition assays were performed using cod and carp extracts and purified recombinant parvalbumin of cod and carp. High crossreactivity among cod and carp parvalbumins was observed in immunoblots as well as in fluid phase assays. Natural and recombinant parvalbumins gave comparable results when performing various in vitro diagnostic assays.

Purification and Characterisation of Relevant Natural and Recombinant Apple Allergens

Apple (Malus domestica) is the most widely cultivated fruit crop in Europe and frequently causes allergic reactions with a variable degree of severity. So far, four apple allergens Mal d 1, Mal d 2, Mal d 3 and Mal d 4 have been identified. Mal d 1, a Bet v 1 related allergen, and Mal d 4, apple profilin, are sensitive to proteolytic degradation, whereas Mal d 2, a thaumatin-like protein and Mal d 3, a nonspecific lipid transfer protein, are rather stable to proteolytic processes. Mal d 1 and Mal d 4 were purified after expression in Escherichia coli expression system, while Mal d 2 and Mal d 3 were purified from apple fruit tissue. All purified proteins were subjected to detailed physicochemical characterisation to confirm their structural integrity and maintained IgE binding capacity. Detailed investigations of carbohydrate moieties of Mal d 2 demonstrated their involvement in the overall IgE binding capacity of this allergen. It was concluded that the folded structure and IgE binding capacity of all four allergens were preserved during purification.

Production of Recombinant Allergens in Plants

A large percentage of allergenic proteins are of plant origin. Hence, plant-based expression systems are considered ideal for the recombinant production of certain allergens. First attempts to establish production of plant-derived allergens in plants focused on transient expression in Nicotiana benthamiana infected with recombinant viral vectors. Accordingly, allergens from birch and mugwort pollen, as well as from apple have been expressed in plants. Production of house dust mite allergens has been achieved by Agrobacterium-mediated transformation of tobacco plants. Beside the use of plants as production systems, other approaches have focused on the development of edible vaccines expressing allergens or epitopes thereof, which bypasses the need of allergen purification. The potential of this approach has been convincingly demonstrated for transgenic rice seeds expressing seven dominant human T cell epitopes derived from Japanese cedar pollen allergens. Parallel to efforts in developing recombinant-based diagnostic and therapeutic reagents, different gene-silencing approaches have been used to decrease the expression of allergenic proteins in allergen sources. In this way hypoallergenic ryegrass, soybean, rice, apple, and tomato were developed.

The Influence of Recombinant Production on the Immunologic Behavior of Birch Pollen Isoallergens

Allergic reactions towards the birch major pollen allergen Bet v 1 are among the most common causes of spring pollinosis in the temperate climate zone of the Northern hemisphere. Natural Bet v 1 is composed of a complex mixture of different isoforms. Detailed analysis of recombinant Bet v 1 isoforms revealed striking differences in immunologic as well as allergenic properties of the molecules, leading to a classification of Bet v 1 isoforms into high, medium, and low IgE binding proteins. Especially low IgE binding Bet v 1 isoforms have been described as ideal candidates for desensitizing allergic patients with allergen specific immunotherapy (SIT). Since diagnosis and therapy of allergic diseases are highly dependent on recombinant proteins, continuous improvement of protein production is an absolute necessity.

Isoform Identification and Characterization of Art V 3, the Lipid-transfer Protein of Mugwort Pollen

Art v 3, the lipid-transfer protein (LTP) of Artemisia vulgaris pollen is a relevant allergen showing frequent cross-reactivity with homologues in other plants. Here we report the identification of four full-length Art v 3 sequences obtained by cDNA cloning using mass spectrometry-based sequencing. Two isoforms, Art v 3.0201 and Art v 3.0301 were expressed as soluble proteins in Escherichia coli Rosetta-gami B(DE3) pLysS using different expression systems. Purified natural and recombinant Art v 3 demonstrated similar secondary structures in circular dichroism analysis. All preparations showed high thermal stability but low resistance to gastric digestion with pepsin. Patient-specific IgE reactivity patterns to natural or recombinant isoallergens were observed among Art v 3-sensitized subjects. Using Immuno Solid-phase Allergen Chip (ISAC) assays, frequent cross-reactivity of Art v 3 with LTPs from peach and hazelnut was shown. The biological activity of both isoforms was comparable to the natural allergen in basophil release assays. The newly identified sequences provide the basis for recombinant mugwort LTP production enabling batch-to-batch reproducibility and thus ensuring high-quality products for diagnosis and therapy.

Development of Recombinant Allergens for Diagnosis and Therapy

Allergic disease represents an increasing problem in industrialized countries. However, allergy diagnosis and specific immunotherapy, the only curative approach towards the treatment of IgE-mediated disorders, are still performed like in their very beginnings more than a century ago. The use of allergen extracts of undefined contents bears the risk of anaphylactic side effects and sensitization to new allergens during immunotherapy. This review focuses on production, physicochemical, and immunological requirements, as well as on the multiple advantages of recombinant allergens and hypoallergens in comparison to conventional allergen extracts used in allergy diagnosis and therapy. Recombinant allergens offer the perspective of molecule-based allergy diagnosis and consequently safe and patient-tailored immunotherapy.

Pichia Pastoris is Superior to E. Coli for the Production of Recombinant Allergenic Non-specific Lipid-transfer Proteins

Non-specific lipid-transfer proteins (nsLTP) from food and pollen are clinically important allergens, especially in patients recruited from the Mediterranean area. For the use of recombinant nsLTPs in allergy diagnosis and preclinical allergy studies the preparation of nsLTPs in a properly folded and biologically active form is required. Using hazelnut nsLTP (Cor a 8) as a model allergen, heterologous over-expression in Escherichia coli and Pichia pastoris was compared. Recombinant Cor a 8 derived from E. coli and P. pastoris was purified by IMAC and SEC or ammonium sulphate precipitation followed by IEC and SEC, respectively. The recombinant proteins were characterized with regard to IgE-binding by immunoblotting and ELISA, structure by N-terminal sequencing, CD-spectroscopy and LS and to their biological activity using an in vitro basophil histamine release assay. Purification of hazelnut nsLTP from bacterial lysate under native conditions resulted in a low yield of Cor a 8. In addition, the preparation contained non-IgE-reactive aggregations besides the IgE-reactive monomer. In contrast, the yield of rCor a 8 produced in P. pastoris was approximately 270-fold higher and impurities with oligomers have not been detected. Purified monomeric Cor a 8 from bacteria and yeast showed similar IgE-antibody reactivity and secondary structures, and both were capable of inducing histamine release from basophils. In summary, P. pastoris is superior to E. coli as expression system for the production of large quantities of soluble, properly folded, and biologically active rCor a 8.

Characterization of Plant Food Allergens: an Overview on Physicochemical and Immunological Techniques

Allergy to plant-derived foods is a highly complex disorder with clinical manifestations ranging from mild oral, gastrointestinal, and cutaneous symptoms to life-threatening systemic conditions. This heterogeneity in clinical manifestations has been attributed to different properties of allergenic molecules. Based on this fact, symptom elicitors were grouped into class I and pollinosis-associated class II food allergens, but clear distinction is rather ambiguous. Moreover, mechanisms underlying food sensitization are not fully understood yet, and food allergy management most often relies on patient's compliance to avoid suspected foods. Therefore, recent efforts aim at the investigation of plant food allergies at the molecular level. This review provides an overview on currently available techniques for allergen characterization and discusses their application for investigation of plant food allergens. Data obtained by an array of physicochemical analyses, such as allergen structure, integrity, aggregation, and stability, need to be linked to results from immunological methods at the level of IgE and T-cell reactivity. Such knowledge allows the development of computational algorithms to predict allergenicity of novel foods being introduced by biotechnological industry. Furthermore, molecular characterization is an indispensable tool for molecule-based diagnosis and future development of safer patient-tailored specific immunotherapy in plant food allergy.

Antigen Aggregation Decides the Fate of the Allergic Immune Response

Previously, defined naturally occurring isoforms of allergenic proteins were classified as hypoallergens and therefore suggested as an agent for immunotherapy in the future. In this paper, we report for the first time the molecular background of hypoallergenicity by comparing the immunological behavior of hyperallergenic Betula verrucosa major Ag 1a (Bet v 1a) and hypoallergenic Bet v 1d, two isoforms of the major birch pollen allergen Betula verrucosa 1. Despite their cross-reactivity, Bet v 1a and Bet v 1d differ in their capacity to induce protective Ab responses in BALB/c mice. Both isoforms induced similar specific IgE levels, but only Bet v 1d expressed relevant titers of serum IgGs and IgAs. Interestingly, hypoallergenic Bet v 1d activated dendritic cells more efficiently, followed by the production of increased amounts of Th1- as well as Th2-type cytokines. Surprisingly, compared with Bet v 1a, Bet v 1d-immunized mice showed a decreased proliferation of regulatory T cells. Crystallographic studies and dynamic light scattering revealed that Bet v 1d demonstrated a high tendency to form disulfide-linked aggregates due to a serine to cysteine exchange at residue 113. We conclude that aggregation of Bet v 1d triggers the establishment of a protective Ab titer and supports a rationale for Bet v 1d being a promising candidate for specific immunotherapy of birch pollen allergy.

Targeting the Cysteine-stabilized Fold of Art V 1 for Immunotherapy of Artemisia Pollen Allergy

Plants of the genus Artemisia domestic in Northern and Central Europe, USA and parts of Asia are a major cause of allergic symptoms from late summer to autumn. Art v 1, the major mugwort pollen allergen appears as two-domain glycoprotein, consisting of an N-terminal defensin-like and a proline/hydroxyproline-rich C-terminal part. Patients sensitized to Art v 1 commonly display IgE antibodies against the cysteine-stabilized defensin fold. Site-directed mutagenesis of eight cysteines was used to disrupt disulfide bonds to generate molecules with altered IgE-binding capacity. Engineered constructs were expressed in E. coli and recombinant proteins were tested for their allergenic and T cell reactivity as well as for their physicochemical characteristics. Three cysteine variants (C22S, C47S, and C49S) exhibited extremely low IgE-binding activity in immunoblot and ELISA using sera from Art v 1-allergic patients. Mediator release assays using rat basophil leukemia cells showed that these variants displayed a 1x10(5)-fold reduced allergenic potency as compared to wild-type protein. All variants were able to activate allergen-specific T cells in PBMC, as well as Art v 1-specific T cell lines and clones. Variant C49S displayed an increased hydrophobic surface potential which correlated with an advanced activation of allergen-specific T cells. The low allergenicity and high immunogenic activity of Art v 1 variant C49S renders the molecule an attractive candidate for hypoallergen-based immunotherapy of Artemisia pollen allergy.

Traces of PFc' in IVIG Interact with Human IgG Fc Domains and Counteract Aggregation

To prevent multimer formation, intravenous immunoglobulin (IVIG) is often treated with traces of pepsin. So far, the mechanism behind this treatment has been unclear. Recently, we reported that human IgG4 binds other IgG molecules via Fc-Fc interactions. Here we show that IVIG treated with traces of pepsin (Nanogam) inhibits these interactions. We found that--besides IgG4--peptides corresponding to IgG1 and IgG2 pFc' (products of limited pepsin digestion) are responsible for the inhibitory action. Using radiolabeled pFc', it was found that pFc' binds directly to IgG1. Furthermore, recombinant CH3 fragments were found to also possess binding activity, and potencies of inhibition varied over 3 orders of magnitude amongst the subclasses, IgG4 being most potent. We propose that pFc' formation explains how limited pepsin digestion diminishes adverse effects of IVIG. In particular, the presence of this fragment can enhance the stability of IgG products including IVIG and therapeutical monoclonal antibodies. Indeed, using a model system it was found that acid-induced aggregation of IgG is reduced in the presence of pFc', suggesting a 'chaperone-like' activity of this fragment. Thus, pFc' can modulate Fc interactions and may therefore reduce adverse effects of IVIG, in particular by preventing oligomerization.

A New Allergen from Ragweed (Ambrosia Artemisiifolia) with Homology to Art V 1 from Mugwort

Art v 1, the major pollen allergen of the composite plant mugwort (Artemisia vulgaris) has been identified recently as a thionin-like protein with a bulky arabinogalactan-protein moiety. A close relative of mugwort, ragweed (Ambrosia artemisiifolia) is an important allergen source in North America, and, since 1990, ragweed has become a growing health concern in Europe as well. Weed pollen-sensitized patients demonstrated IgE reactivity to a ragweed pollen protein of apparently 29-31 kDa. This reaction could be inhibited by the mugwort allergen Art v 1. The purified ragweed pollen protein consisted of a 57-amino acid-long defensin-like domain with high homology to Art v 1 and a C-terminal proline-rich domain. This part contained hydroxyproline-linked arabinogalactan chains with one galactose and 5 to 20 and more alpha-arabinofuranosyl residues with some beta-arabinoses in terminal positions as revealed by high field NMR. The ragweed protein contained only small amounts of the single hydroxyproline-linked beta-arabinosyl residues, which form an important IgE binding determinant in Art v 1. cDNA clones for this protein were obtained from ragweed flowers. Immunological characterization revealed that the recombinant ragweed protein reacted with >30% of the weed pollen allergic patients. Therefore, this protein from ragweed pollen constitutes a novel important ragweed allergen and has been designated Amb a 4.

Diclofenac Hypersensitivity: Antibody Responses to the Parent Drug and Relevant Metabolites

Hypersensitivity reactions against nonsteroidal antiinflammatory drugs (NSAIDs) like diclofenac (DF) can manifest as Type I-like allergic reactions including systemic anaphylaxis. However, except for isolated case studies experimental evidence for an IgE-mediated pathomechanism of DF hypersensitivity is lacking. In this study we aimed to investigate the possible involvement of drug- and/or metabolite-specific antibodies in selective DF hypersensitivity.

Reshaping the Bet V 1 Fold Modulates T(H) Polarization

Several alternative mechanisms have been proposed to explain why some proteins are able to induce a T(H)2-biased and IgE-mediated immune response. These include specific interactions with receptors of the innate immune system, proteolytic activities, allergen-associated carbohydrate structures, and intrinsic structural determinants.

Mechanisms of Allergen-antibody Interaction of Cockroach Allergen Bla G 2 with Monoclonal Antibodies That Inhibit IgE Antibody Binding

Cockroach allergy is strongly associated with asthma, and involves the production of IgE antibodies against inhaled allergens. Reports of conformational epitopes on inhaled allergens are limited. The conformational epitopes for two specific monoclonal antibodies (mAb) that interfere with IgE antibody binding were identified by X-ray crystallography on opposite sites of the quasi-symmetrical cockroach allergen Bla g 2.

Physicochemical and Biological Characterization of 1E10 Anti-idiotype Vaccine

1E10 monoclonal antibody is a murine anti-idiotypic antibody that mimics N-glycolyl-GM3 gangliosides. This antibody has been tested as an anti-idiotypic cancer vaccine, adjuvated in Al(OH)3, in several clinical trials for melanoma, breast, and lung cancer. During early clinical development this mAb was obtained in vivo from mice ascites fluid. Currently, the production process of 1E10 is being transferred from the in vivo to a bioreactor-based method.

Waiting
simple hit counter