Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Jørgen Nedergaard Larsen is active.

Publication


Featured researches published by Jørgen Nedergaard Larsen.


Journal of Immunology | 2000

Dominant Epitopes and Allergic Cross-Reactivity: Complex Formation Between a Fab Fragment of a Monoclonal Murine IgG Antibody and the Major Allergen from Birch Pollen Bet v 1

Osman Mirza; Anette Henriksen; H. Ipsen; Jørgen Nedergaard Larsen; M. Wissenbach; Michael D. Spangfort; Michael Gajhede

The symptoms characteristic of allergic hypersensitivity are caused by the release of mediators, i.e., histamine, from effector cells such as basophils and mast cells. Allergens with more than one B cell epitope cross-link IgE Abs bound to high affinity FcεRI receptors on mast cell surfaces leading to aggregation and subsequent mediator release. Thus, allergen-Ab complexes play a crucial role in the cascade leading to the allergic response. We here report the structure of a 1:1 complex between the major birch pollen allergen Bet v 1 and the Fab fragment from a murine monoclonal IgG1 Ab, BV16, that has been solved to 2.9 Å resolution by x-ray diffraction. The mAb is shown to inhibit the binding of allergic patients’ IgE to Bet v 1, and the allergen-IgG complex may therefore serve as a model for the study of allergen-IgE interactions relevant in allergy. The size of the BV16 epitope is 931 Å2 as defined by the Bet v 1 Ab interaction surface. Molecular interactions predicted to occur in the interface are likewise in agreement with earlier observations on Ag-Ab complexes. The epitope is formed by amino acids that are conserved among major allergens from related species within the Fagales order. In combination with a surprisingly high inhibitory capacity of BV16 with respect to allergic patients’ serum IgE binding to Bet v 1, these observations provide experimental support for the proposal of dominant IgE epitopes located in the conserved surface areas. This model will facilitate the development of new and safer vaccines for allergen immunotherapy in the form of mutated allergens.


Proteins | 2001

Major venom allergen of yellow jackets, Ves v 5: Structural characterization of a pathogenesis-related protein superfamily

Anette Henriksen; Te P. King; Osman Mirza; Rafael I. Monsalve; Kåre Meno; H. Ipsen; Jørgen Nedergaard Larsen; Michael Gajhede; Michael D. Spangfort

Ves v 5 is one of three major allergens found in yellow‐jacket venom: phospholipase A1 (Ves v 1), hyaluronidase (Ves v 2), and antigen 5 (Ves v 5). Ves v 5 is related by high amino acid sequence identity to pathogenesis‐related proteins including proteins from mammals, reptiles, insects, fungi, and plants. The crystal structure of Ves v 5 has been solved and refined to a resolution of 1.9 Å. The majority of residues conserved between the pathogenesis‐related proteins can be rationalized in terms of hydrogen bonding patterns and hydrophobic interactions defining an α‐β‐α sandwich core structure. A small number of consensus residues are solvent exposed (including two adjacent histidines) and located in an elongated cavity that forms a putative active site. The site has no structural resemblance to previously characterized enzymes. Homologous antigen 5s from a large number of different yellow jackets, hornets, and paper wasps are known and patients show varying extents of cross‐reactivity to the related antigen 5s. The structure of Ves v 5 allows a detailed analysis of the epitopes that may participate in antigenic cross‐reactivity, findings that are useful for the development of a vaccine for treatment of insect allergy. Proteins 2001;45:438–448.


Journal of Immunology | 2003

Dominating IgE-Binding Epitope of Bet v 1, the Major Allergen of Birch Pollen, Characterized by X-ray Crystallography and Site-Directed Mutagenesis

Michael D. Spangfort; Osman Mirza; H. Ipsen; R.J.Joost van Neerven; Michael Gajhede; Jørgen Nedergaard Larsen

Specific allergy vaccination is an efficient treatment for allergic disease; however, the development of safer vaccines would enable a more general use of the treatment. Determination of molecular structures of allergens and allergen-Ab complexes facilitates epitope mapping and enables a rational approach to the engineering of allergen molecules with reduced IgE binding. In this study, we describe the identification and modification of a human IgE-binding epitope based on the crystal structure of Bet v 1 in complex with the BV16 Fab′ fragment. The epitope occupies ∼10% of the molecular surface area of Bet v 1 and is clearly conformational. A synthetic peptide representing a sequential motif in the epitope (11 of 16 residues) did not inhibit the binding of mAb BV16 to Bet v 1, illustrating limitations in the use of peptides for B cell epitope characterization. The single amino acid substitution, Glu45-Ser, was introduced in the epitope and completely abolished the binding of mAb BV16 to the Bet v 1 mutant within a concentration range 1000-fold higher than wild type. The mutant also showed up to 50% reduction in the binding of human polyclonal IgE, demonstrating that glutamic acid 45 is a critical amino acid also in a major human IgE-binding epitope. By solving the three-dimensional crystal structure of the Bet v 1 Glu45-Ser mutant, it was shown that the change in immunochemical activity is directly related to the Glu45-Ser substitution and not to long-range structural alterations or collapse of the Bet v 1 mutant tertiary structure.


Molecular Immunology | 1992

PCR based cloning and sequencing of isogenes encoding the tree pollen major allergen Car b I from Carpinus betulus, hornbeam

Jørgen Nedergaard Larsen; Per Strøman; H. Ipsen

Cloning of the gene encoding the major allergen, Car b I, from Carpinus betulus (hornbeam) pollen was performed using the Polymerase Chain Reaction (PCR) to specifically amplify the gene of interest using single stranded cDNA as template. Specific primers, deduced from the aminoterminal sequence of the purified protein, were tailored to facilitate direct expression of plasmic clones, and the large fraction of positive clones obtained, revealed the presence of isogenic variation. Three clones were characterized in detail by antibody based assays and nucleotide sequencing. The recombinant allergens were shown by crossed immunoelectrophoresis (CIE) to precipitate with monospecific polyclonal rabbit antibodies raised against purified Bet v I, by crossed radioimmunoelectrophoresis (CRIE) to bind tree pollen allergic patient serum IgE, and by immunoblotting to bind murine monoclonal antibodies, raised against purified Car b I from pollen. Car b I is encoded by a 159-triplets open reading frame. The molecular masses (M(r) = 17272, 17355 and 17217 Da, respectively), the amino acid composition, and the aminoterminal sequence of the predicted polypeptides agree well with data obtained by analysis of the protein purified from pollen. The deduced amino acid sequences show pronounced homology (73, 75 and 74% identities respectively) to Bet v I, the major allergen from Betula verrucosa (white birch) pollen. Soluble recombinant Car b I, without a fusion partner, was produced in Escherichia coli with an immunochemical reactivity closely resembling that of the native pollen allergen. The tree pollen major allergens therefore constitute an ideal system for the study of allergenic epitopes.


Journal of Immunology | 2004

Allergy Vaccine Engineering: Epitope Modulation of Recombinant Bet v 1 Reduces IgE Binding but Retains Protein Folding Pattern for Induction of Protective Blocking-Antibody Responses

Jens Holm; Michael Gajhede; Mercedes Ferreras; Anette Henriksen; H. Ipsen; Jørgen Nedergaard Larsen; Lise Lund; Henrik Hugo Jacobi; Anders Millner; Peter Adler Würtzen; Michael D. Spangfort

Human type 1 immediate allergic response symptoms are caused by mediator release from basophils and mast cells. This event is triggered by allergens aggregating preformed IgE Abs bound to the high-affinity receptor (FcεRI) on these cells. Thus, the allergen/IgE interaction is crucial for the cascade leading to the allergic and anaphylactic response. Two genetically engineered forms of the white birch pollen major allergen Bet v 1 with point mutations directed at molecular surfaces have been characterized. Four and nine point mutations led to a significant reduction of the binding to human serum IgE, suggesting a mutation-induced distortion of IgE-binding B cell epitopes. In addition, the mutated allergens showed a decrease in anaphylactic potential, because histamine release from human basophils was significantly reduced. Retained α-carbon backbone folding pattern of the mutated allergens was indicated by x-ray diffraction analysis and circular dichroism spectroscopy. The rBet v 1 mutants were able to induce proliferation of T cell lines derived from birch pollen allergic patients. The stimulation indices were similar to the indices of nonmutated rBet v 1 and natural Bet v 1 purified from birch pollen. The ability of anti-rBet v 1 mutant specific mouse IgG serum to block binding of human serum IgE to rBet v 1 demonstrates that the engineered rBet v 1 mutants are able to induce Abs reactive with nonmodified Bet v 1. rBet v 1 mutants may constitute vaccine candidates with improved efficacy/safety profiles for safer allergy vaccination.


Journal of Immunology | 2005

The Crystal Structure of Recombinant proDer p 1, a Major House Dust Mite Proteolytic Allergen

K. Meno; Peter Thorsted; H. Ipsen; Ole Kristensen; Jørgen Nedergaard Larsen; Michael D. Spangfort; Michael Gajhede; Kaare Lund

Allergy to house dust mite is among the most prevalent allergic diseases worldwide. Most house dust mite allergic patients react to Der p 1 from Dermatophagoides pteronyssinus, which is a cysteine protease. To avoid heterogeneity in the sample used for crystallization, a modified recombinant molecule was produced. The sequence of the proDer p 1 allergen was modified to reduce glycosylation and to abolish enzymatic activity. The resulting rproDer p 1 preparation was homogenous and stable and yielded crystals diffracting to a resolution of 1.61 Å. The active site is located in a large cleft on the surface of the molecule. The 80-aa pro-peptide adopts a unique fold that interacts with the active site cleft and a substantial adjacent area on the mature region, excluding access to the cleft and the active site. Studies performed using crossed-line immunoelectrophoresis and IgE inhibition experiments indicated that several epitopes are covered by the pro-peptide and that the epitopes on the recombinant mature molecule are indistinguishable from those on the natural one. The structure confirms previous results suggesting a preference for aliphatic residues in the important P2 position in substrates. Sequence variations in related species are concentrated on the surface, which explains the existence of cross-reacting and species-specific antibodies. This study describes the first crystal structure of one of the clinically most important house dust mite allergens, the cysteine protease Der p 1.


Clinical & Experimental Allergy | 2006

Inhibition of rBet v 1-induced basophil histamine release with specific immunotherapy -induced serum immunoglobulin G: no evidence that FcγRIIB signalling is important

A.M. Ejrnaes; M. Svenson; G. Lund; Jørgen Nedergaard Larsen; Henrik Hugo Jacobi

Background Human basophils and mast cells express the low‐affinity immunoglobulin (Ig)G receptor FcγRIIB. It has previously been shown in artificial model systems that cross‐linking of the high‐affinity IgE receptor FcɛRI and FcγRIIB leads to inhibition of FcɛRI signalling.


The Journal of Allergy and Clinical Immunology | 1988

The collaborative study of the international standard of dog, Canis domesticus, hair/dander extract

Jørgen Nedergaard Larsen; Annette W. Ford; Birgitte Gjesing; David A. Levy; Bogdan Petrunov; Louis Silvestri; Henning Lewenstein

A collaborative study was carried out to assess the suitability of a chosen preparation to serve as the international standard (IS) for dog (Canis domesticus) hair/dander extract. Sets of five coded preparations of dog extract, including the proposed IS, were delivered to each participating laboratory in glass-sealed ampules. Fifteen laboratories in nine different countries examined the preparations by RAST inhibition, crossed immunoelectrophoresis/crossed radioimmunoelectrophoresis, histamine release, and by other methods. In spite of the use of different versions of methods and different reagents, quite consistent results were obtained, and the proposed IS was found to have a satisfactory activity in all assays and to be useful as a calibrator when allergenic potency of similar dog allergenic extracts was estimated. Four laboratories estimated the specific content of allergens Ag 3, Ag 13, and albumin and found the proposed IS to be a suitable standard for these assays. On the basis of the results from this study, the World Health Organization established the preparation as the international standard for dog hair/dander extract with an assigned unitage of 100,000 IU per ampule. The units refer to both the total allergenic activity of the ampule and to that of individual allergens.


Journal of Chromatography B: Biomedical Sciences and Applications | 2001

Molecular basis of allergic cross-reactivity between group 1 major allergens from birch and apple

Jens Holm; G. Bærentzen; Michael Gajhede; H. Ipsen; Jørgen Nedergaard Larsen; H. Løwenstein; M. Wissenbach; Michael D. Spangfort

Patients allergic to birch pollen often also react with fruits and vegetables, such as apple. The major cause of cross-reactivity between birch and apple is biochemical and immunological similarity between the major allergens, Bet v 1 and Mal d 1, as demonstrated by serological and cellular immunoassays. In addition, birch pollen-specific therapeutic allergy vaccination has been shown to improve allergic symptoms caused by oral ingestion of apple. Detailed analysis of molecular surface areas based on the crystal structure of Bet v 1, and primary sequence alignment, identify potential epitopes for cross-reactive antibodies. Two or more conserved patches are identified when comparing Bet v 1 and Mal d 1, thus providing a molecular model for serological cross-reactivity involving more than one IgE-binding epitope. A minimum of two epitopes would be necessary for cross-linking of receptor bound IgE in functional histamine release assays and skin test. Individual amino acid substitutions, as occurring in isoallergenic variation, may, however, have a dramatic effect on epitope integrity if critical residues are affected. Thus, one area large enough to accommodate antibody-binding epitopes shared by all known Mal d 1 isoallergens and variants is identified, as well as areas shared by Bet v 1 and individual Mal d 1 isoallergens or variants. The occurrence of limited epitope coincidence between Bet v 1 and Mal d 1 is in agreement with the observation that some, but not all, birch pollen allergic patients react with apple, and that the epitope repertoire recognised by the IgE of the individual patients determines the degree of cross-reactivity.


FEBS Letters | 2005

Structure of the house dust mite allergen Der f 2: implications for function and molecular basis of IgE cross-reactivity.

Birthe R. Johannessen; Lars K. Skov; Jette S. Kastrup; Ole Kristensen; Caroline Bolwig; Jørgen Nedergaard Larsen; Michael D. Spangfort; Kaare Lund; Michael Gajhede

The X‐ray structure of the group 2 major allergen from Dermatophagoides farinae (Der f 2) was determined to 1.83 Å resolution. The overall Der f 2 structure comprises a single domain of immunoglobulin fold with two anti‐parallel β‐sheets. A large hydrophobic cavity is formed in the interior of Der f 2. Structural comparisons to distantly related proteins suggest a role in lipid binding. Immunoglobulin E (IgE) cross‐reactivity between group 2 house dust mite major allergens can be explained by conserved surface areas representing IgE binding epitopes.

Collaboration


Dive into the Jørgen Nedergaard Larsen's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Henrik Ipsen

University of Copenhagen

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge