Mirela Curin

MPB2C, a microtubule-associated plant protein binds to and interferes with cell-to-cell transport of tobacco mosaic virus movement protein

The movement protein of tobacco mosaic virus, MP30, mediates viral cell-to-cell transport via plasmodesmata. The complex MP30 intra- and intercellular distribution pattern includes localization to the endoplasmic reticulum, cytoplasmic bodies, microtubules, and plasmodesmata and likely requires interaction with plant endogenous factors. We have identified and analyzed an MP30-interacting protein, MPB2C, from the host plant Nicotiana tabacum. MPB2C constitutes a previously uncharacterized microtubule-associated protein that binds to and colocalizes with MP30 at microtubules. In vivo studies indicate that MPB2C mediates accumulation of MP30 at microtubules and interferes with MP30 cell-to-cell movement. In contrast, intercellular transport of a functionally enhanced MP30 mutant, which does not accumulate and colocalize with MP30 at microtubules, is not impaired by MPB2C. Together, these data support the concept that MPB2C is not required for MP30 cell-to-cell movement but may act as a negative effector of MP30 cell-to-cell transport activity.

Mold Allergens in Respiratory Allergy: From Structure to Therapy

Allergic reactions to fungi were described 300 years ago, but the importance of allergy to fungi has been underestimated for a long time. Allergens from fungi mainly cause respiratory and skin symptoms in sensitized patients. In this review, we will focus on fungi and fungal allergens involved in respiratory forms of allergy, such as allergic rhinitis and asthma. Fungi can act as indoor and outdoor respiratory allergen sources, and depending on climate conditions, the rates of sensitization in individuals attending allergy clinics range from 5% to 20%. Due to the poor quality of natural fungal allergen extracts, diagnosis of fungal allergy is hampered, and allergen-specific immunotherapy is rarely given. Several factors are responsible for the poor quality of natural fungal extracts, among which the influence of culture conditions on allergen contents. However, molecular cloning techniques have allowed us to isolate DNAs coding for fungal allergens and to produce a continuously growing panel of recombinant allergens for the diagnosis of fungal allergy. Moreover, technologies are now available for the preparation of recombinant and synthetic fungal allergen derivatives which can be used to develop safe vaccines for the treatment of fungal allergy.

Skin prick test extracts for dog allergy diagnosis show considerable variations regarding the content of major and minor dog allergens.

Background: Commercial skin prick test (SPT) extracts used for the diagnosis of dog allergy are prepared by extracting allergens from natural sources, e.g. dog hair and dander. Due to different starting material and extraction methods used, it is likely that extracts differ regarding their allergen contents. Methods: The total protein content and composition of dog SPT extracts from 5 European manufacturers were compared by silver-stained SDS-PAGE. Specific antibody probes were generated to detect major and minor allergens in each extract by immunoblotting. Additionally, sera of patients suffering from dog allergy were used to detect dog allergens in SPT extracts. Results: SPT extracts showed a 20-fold variation regarding the total protein content. The contents of the major dog allergen Can f 1 and of Can f 2 varied considerably between the extracts. In one of the extracts, neither Can f 1 nor Can f 2 could be detected by immunoblotting. The contents of the minor dog allergen Can f 3, albumin, also showed great variability. In one of the dog SPT extracts, the presence of human serum albumin (HSA) was detected with HSA-specific antibodies. Conclusion: The observed variability of commercial dog SPT extracts regarding their allergen contents likely has a negative influence on the accuracy of diagnosis of dog allergy.

MPB2C, a Microtubule-Associated Plant Factor, Is Required for Microtubular Accumulation of Tobacco Mosaic Virus Movement Protein in Plants

Movement protein binding 2C (MPB2C) is a plant endogenous microtubule-associated protein previously identified as an interaction partner of tobacco (Nicotiana tabacum) mosaic virus movement protein (TMV-MP). In this work, the role of MPB2C in cell-to-cell transport of TMV-MP, viral spread of TMV, and subcellular localization of TMV-MP was examined. To this end, plants with reduced MPB2C levels were generated by a gene-silencing strategy. Local and systemic spread of TMV and cell-to-cell movement of TMV-MP were unimpaired in MPB2C-silenced plants as compared to nonsilenced plants, indicating that MPB2C is not required for intercellular transport of TMV-MP itself or spread of TMV. However, a clear change in subcellular distribution of TMV-MP characterized by a nearly complete loss of microtubular localization was observed in MPB2C-silenced plants. This result shows that the MPB2C is a central player in determining the complex subcellular localization of TMV-MP, in particular its microtubular accumulation, a phenomenon that has been frequently observed and whose role is still under discussion. Clearly, MPB2C mediated accumulation of TMV-MP at microtubules is not required for intercellular spread but may be a means to withdraw the TMV-MP from the cell-to-cell transport pathway.

Paving the way of systems biology and precision medicine in allergic diseases: the MeDALL success story: Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015.

MeDALL (Mechanisms of the Development of ALLergy; EU FP7‐CP‐IP; Project No: 261357; 2010–2015) has proposed an innovative approach to develop early indicators for the prediction, diagnosis, prevention and targets for therapy. MeDALL has linked epidemiological, clinical and basic research using a stepwise, large‐scale and integrative approach: MeDALL data of precisely phenotyped children followed in 14 birth cohorts spread across Europe were combined with systems biology (omics, IgE measurement using microarrays) and environmental data. Multimorbidity in the same child is more common than expected by chance alone, suggesting that these diseases share causal mechanisms irrespective of IgE sensitization. IgE sensitization should be considered differently in monosensitized and polysensitized individuals. Allergic multimorbidities and IgE polysensitization are often associated with the persistence or severity of allergic diseases. Environmental exposures are relevant for the development of allergy‐related diseases. To complement the population‐based studies in children, MeDALL included mechanistic experimental animal studies and in vitro studies in humans. The integration of multimorbidities and polysensitization has resulted in a new classification framework of allergic diseases that could help to improve the understanding of genetic and epigenetic mechanisms of allergy as well as to better manage allergic diseases. Ethics and gender were considered. MeDALL has deployed translational activities within the EU agenda.

Paving the way of systems biology and precision medicine in allergic diseases

MeDALL (Mechanisms of the Development of ALLergy; EU FP7‐CP‐IP; Project No: 261357; 2010–2015) has proposed an innovative approach to develop early indicators for the prediction, diagnosis, prevention and targets for therapy. MeDALL has linked epidemiological, clinical and basic research using a stepwise, large‐scale and integrative approach: MeDALL data of precisely phenotyped children followed in 14 birth cohorts spread across Europe were combined with systems biology (omics, IgE measurement using microarrays) and environmental data. Multimorbidity in the same child is more common than expected by chance alone, suggesting that these diseases share causal mechanisms irrespective of IgE sensitization. IgE sensitization should be considered differently in monosensitized and polysensitized individuals. Allergic multimorbidities and IgE polysensitization are often associated with the persistence or severity of allergic diseases. Environmental exposures are relevant for the development of allergy‐related diseases. To complement the population‐based studies in children, MeDALL included mechanistic experimental animal studies and in vitro studies in humans. The integration of multimorbidities and polysensitization has resulted in a new classification framework of allergic diseases that could help to improve the understanding of genetic and epigenetic mechanisms of allergy as well as to better manage allergic diseases. Ethics and gender were considered. MeDALL has deployed translational activities within the EU agenda.

Specific IgE and IgG measured by the MeDALL allergen-chip depend on allergen and route of exposure: The EGEA study

Background: The nature of allergens and route and dose of exposure may affect the natural development of IgE and IgG responses. Objective: We sought to investigate the natural IgE and IgG responses toward a large panel of respiratory and food allergens in subjects exposed to different respiratory allergen loads. Methods: A cross‐sectional analysis was conducted in 340 adults of the EGEA (Epidemiological study of the Genetics and Environment of Asthma, bronchial hyperresponsiveness and atopy) (170 with and 170 without asthma) cohort. IgE and IgG responses to 47 inhalant and food allergen components were analyzed in sera using allergen microarray and compared between 5 French regions according to the route of allergen exposure (inhaled vs food allergens). Results: Overall 48.8% of the population had allergen‐specific IgE levels of 0.3 ISAC standardized units (ISU) or more to at least 1 of the 47 allergens with no significant differences across the regions. For ubiquitous respiratory allergens (ie, grass, olive/ash pollen, house dust mites), specific IgE did not show marked differences between regions and specific IgG (≥0.5 ISU) was present in most subjects everywhere. For regionally occurring pollen allergens (ragweed, birch, cypress), IgE sensitization was significantly associated with regional pollen exposure. For airborne allergens cross‐reacting with food allergens, frequent IgG recognition was observed even in regions with low allergen prevalence (Bet v 1) or for allergens less frequently recognized by IgE (profilins). Conclusions: The variability in allergen‐specific IgE and IgG frequencies depends on exposure, route of exposure, and overall immunogenicity of the allergen. Allergen contact by the oral route might preferentially induce IgG responses.

Hypoallergenic derivatives of Fel d 1 obtained by rational reassembly for allergy vaccination and tolerance induction

The major cat allergen Fel d 1 represents one of the most important respiratory allergens. Aim of this study was to engineer recombinant Fel d 1 derivatives with reduced IgE reactivity and preserved T cell epitopes for vaccination and tolerance induction.

Mechanisms of the Development of Allergy (MeDALL): Introducing novel concepts in allergy phenotypes

&NA; Asthma, rhinitis, and eczema are complex diseases with multiple genetic and environmental factors interlinked through IgE‐associated and non–IgE‐associated mechanisms. Mechanisms of the Development of ALLergy (MeDALL; EU FP7‐CP‐IP; project no: 261357; 2010‐2015) studied the complex links of allergic diseases at the clinical and mechanistic levels by linking epidemiologic, clinical, and mechanistic research, including in vivo and in vitro models. MeDALL integrated 14 European birth cohorts, including 44,010 participants and 160 cohort follow‐ups between pregnancy and age 20 years. Thirteen thousand children were prospectively followed after puberty by using a newly standardized MeDALL Core Questionnaire. A microarray developed for allergen molecules with increased IgE sensitivity was obtained for 3,292 children. Estimates of air pollution exposure from previous studies were available for 10,000 children. Omics data included those from historical genome‐wide association studies (23,000 children) and DNA methylation (2,173), targeted multiplex biomarker (1,427), and transcriptomic (723) studies. Using classical epidemiology and machine‐learning methods in 16,147 children aged 4 years and 11,080 children aged 8 years, MeDALL showed the multimorbidity of eczema, rhinitis, and asthma and estimated that only 38% of multimorbidity was attributable to IgE sensitization. MeDALL has proposed a new vision of multimorbidity independent of IgE sensitization, and has shown that monosensitization and polysensitization represent 2 distinct phenotypes. The translational component of MeDALL is shown by the identification of a novel allergic phenotype characterized by polysensitization and multimorbidity, which is associated with the frequency, persistence, and severity of allergic symptoms. The results of MeDALL will help integrate personalized, predictive, preventative, and participatory approaches in allergic diseases.

The cat lipocalin Fel d 7 and its cross-reactivity with the dog lipocalin Can f 1.

We investigated the prevalence of sensitization to the cat lipocalin Fel d 7 among 140 cat‐sensitized Swedish patients and elucidated its allergenic activity and cross‐reactivity with the dog lipocalin Can f 1. Sixty‐five of 140 patients had IgE to rFel d 7 whereof 60 also had IgE to rCan f 1. A moderate correlation between IgE levels to rFel d 7 and rCan f 1 was found. rFel d 7 activated basophils in vitro and inhibited IgE binding to rCan f 1 in 4 of 13 patients, whereas rCan f 1 inhibited IgE binding to rFel d 7 in 7 of 13 patients. Fel d 7 and Can f 1 showed high similarities in protein structure and epitopes in common were found using cross‐reactive antisera. Fel d 7 is a common allergen in a Swedish cat‐sensitized population that cross‐reacts with Can f 1, and may contribute to symptoms in cat‐ but also in dog‐allergic patients.