Christof Ebner

Genetic engineering of a hypoallergenic trimer of the major birch pollen allergen Bet v 1

An estimated 100 million individuals suffer from birch pollen allergy. Specific immunotherapy, the only curative allergy treatment, can cause life‐threatening anaphylactic side effects. Here, we report the genetic engineering of a recombinant trimer consisting of three covalently linked copies of the major birch pollen allergen, Bet v 1. The trimer exhibited profoundly reduced allergenic activity but contained similar secondary structures such as Bet v 1 wild type, Bet v 1‐specific B cell and T‐cell epitopes, and induced Th1 cytokine release. As immunogen, rBet v 1 trimer induced IgG antibodies, which blocked patients’ IgE binding to Bet v 1 and related allergens. Thus, rBet v 1 trimer represents a novel hypoallergenic vaccine prototype for treatment of one of the most frequent allergy forms.

The Spectrum of Allergens in Ragweed and Mugwort Pollen

Ragweed and mugwort are important allergenic weeds belonging to the Asteraceae or Compositae plant family. Pollen of mugwort is one of the main causes of allergic reactions in late summer and autumn in Europe and affects about 10–14% of the patients suffering from pollinosis. Ragweed pollen represents the major source of allergenic protein in the United States, with a prevalence of about 50% in atopic individuals. In Europe, ragweed allergy is now rapidly increasing particularly in certain areas in France, Italy, Austria, Hungary, Croatia, and Bulgaria. Amb a 1 and Art v 1, the major allergens of ragweed and mugwort, respectively, are unrelated proteins. Amb a 1 is an acidic 38-kDa nonglycosylated protein. The natural protein undergoes proteolysis during purification and is cleaved into a 26-kDa alpha chain, which associates noncovalently with the beta chain of 12 kDa. The two-chain form seems to be immunologically indistinguishable from the full-length molecule. Art v 1 is a basic glycoprotein comprising two domains: an N-terminal cysteine-rich, defensin-like domain and a C-terminal proline/hydroxyproline-rich module. The proline/hydroxyproline-rich domain was recently shown to contain two types of glycosylation: (1) a large hydroxyproline-linked arabinogalactan composed of a short β1,6-galactan core substituted by a variable number (5–28) of α-arabinofuranose residues forming branched side chains with 5-, 2,5-, 3,5-, and 2,3,5-substituted arabinoses, and (2) single and adjacent β-arabinofuranoses linked to hydroxyproline. As described for other pollen, ragweed and mugwort pollen also contain the pan-allergen profilin and calcium-binding proteins, which are responsible for extensive cross-reactivity among pollen-sensitized patients.

A Novel Approach to Specific Allergy Treatment: The Recombinant Fusion Protein of a Bacterial Cell Surface (S-Layer) Protein and the Major Birch Pollen Allergen Bet v 1 (rSbsC-Bet v 1) Combines Reduced Allergenicity with Immunomodulating Capacity

Counterregulating the disease-eliciting Th2-like immune response of allergen-specific Th lymphocytes by fostering an allergen-specific Th1-like response is a promising concept for future immunotherapy of type I allergy. The use of recombinant allergens combined with more functional adjuvants has been proposed. In this respect, we present a novel approach. The gene sequence encoding the major birch pollen allergen, Bet v 1, was fused with the gene encoding the bacterial cell surface (S-layer) protein of Geobacillus stearothermophilus, resulting in the recombinant protein, rSbsC-Bet v 1. rSbsC-Bet v 1 contained all relevant Bet v 1-specific B and T cell epitopes, but was significantly less efficient to release histamine than rBet v 1. In cells of birch pollen-allergic individuals, rSbsC-Bet v 1 induced IFN-γ along with IL-10, but no Th2-like response, as observed after stimulation with Bet v 1. Intracellular cytokine staining revealed that rSbsC-Bet v 1 promoted IFN-γ-producing Th cells. Moreover, rSbsC-Bet v 1 induced IFN-γ synthesis in Bet v 1-specific Th2 cell clones, and importantly, increased IL-10 production in these cells. In conclusion, genetic fusion of an allergen to S-layer proteins combined reduced allergenicity with immunomodulatory capacity. The strategy described in this work may be generally applied to design vaccines for specific immunotherapy of type I allergy with improved efficacy and safety.

Molecular characterization of wheat allergens specifically recognized by patients suffering from wheat-induced respiratory allergy

Wheat (Triticum aestivum) is an important allergen source responsible for various clinical manifestations of allergy (i.e. food allergy, pollen allergy, respiratory allergy to flour‐Bakers asthma).

Molecular and immunological characterization of novel weed pollen pan-allergens

Background:u2002 Pan‐allergens like profilins, calcium‐binding proteins (CBPs), and nonspecific lipid transfer proteins have been suggested as possible specific markers for multiple pollen sensitizations, and could be used to predict cross‐sensitization/poly‐sensitization to several pollen allergens. Therefore, the purification and characterization of cross‐reacting allergens in pollen is an extremely important task towards correct allergy diagnosis.

Characterization of the T cell response to the major hazelnut allergen, Cor a 1.04: evidence for a relevant T cell epitope not cross‐reactive with homologous pollen allergens

Background IgE antibodies specific for the major birch‐pollen allergen, Bet v 1, cross‐react with homologous allergens in particular foods, e.g. apples, carrots and hazelnuts. In a high number of tree pollen‐allergic individuals, this cross‐reactivity causes clinical symptoms, commonly known as the ‘birch‐fruit‐syndrome’.

Alternaria alternata NADP‐dependent mannitol dehydrogenase is an important fungal allergen

Background Alternaria alternata is one of the most important allergenic fungi worldwide. Mannitol dehydrogenase (MtDH) has previously been shown to be a major allergen of Cladosporium herbarum and cross‐reactivity has been demonstrated for several fungal allergens.

A 246-km continuous running race causes significant changes in bone metabolism

BACKGROUNDnRegular physical exercise exerts a favorable effect on the skeleton. However, excessive physical exercise may have detrimental effects. A low bone mineral density (BMD) has been registered in highly trained runners. The aim of the present study was to evaluate potential effects of the Spartathlon, an annual ultramarathon race of 246 km, on bone metabolism.nnnMETHODSnVenous blood samples were taken before and within 15 min after the end of the race as well as three days after the start of the race. The following variables of bone metabolism were studied: osteocalcin (Oc), cross-linked-C-telopeptide of type I collagen (CTX), osteoprotegerin (OPG), and its ligand, receptor activator of nuclear factor kappaB ligand (RANKL).nnnRESULTSnBlood samples were taken from 18 runners (16 men and 2 women) at the three time points. The median time taken by the runners to complete the race was 32 h and 52 min. Serum levels of CTX were significantly increased immediately after the race as well as three days after the start of the race compared with the time prior to the race. Oc was transiently suppressed after the race. Serum levels of RANKL and OPG were increased three days after the start of the race compared to the time before the start of the race.nnnCONCLUSIONSnThis study showed that an ultra-distance run of nearly 250 km induced changes in RANK/RANKL/OPG interaction, which suggests a transient uncoupling of bone metabolism, increased bone resorption, and suppressed bone formation.

Differences in the intrinsic immunogenicity and allergenicity of Bet v 1 and related food allergens revealed by site‐directed mutagenesis

Birch pollen allergies are frequently associated with adverse reactions to various fruits, nuts, or vegetables, described as pollen–food syndrome (PFS) and caused by cross‐reactive IgE antibodies primarily directed against Bet v 1. Specific immunotherapy (SIT) represents an effective treatment for inhalant allergies; however, successful birch pollen SIT does not correlate well with the amelioration of concomitant food allergies.

Allergen hybrids - next generation vaccines for Fagales pollen immunotherapy.

Trees belonging to the order of Fagales show a distinct geographical distribution. While alder and birch are endemic in the temperate zones of the Northern Hemisphere, hazel, hornbeam and oak prefer a warmer climate. However, specific immunotherapy of Fagales pollen‐allergic patients is mainly performed using birch pollen extracts, thus limiting the success of this intervention in birch‐free areas.