Pollen allergen Ole e 7 Antibody

What is Ole e 7 and what are its main molecular properties?

Ole e 7 is an allergen isolated from olive tree (Olea europaea) pollen that belongs to the nonspecific lipid transfer protein (nsLTP) family. It is a non-glycosylated protein with a molecular mass ranging between 9875 d to 10,297 d (approximately 9.5 kDa) . The allergen exhibits a high degree of polymorphism, which contributes to its varied immunological properties . Initial characterization through N-terminal sequencing of 21 amino acid residues from two isoforms revealed no homology with proteins contained in database banks at the time of its initial isolation .

How does Ole e 7 compare structurally to other allergens in the Olea europaea pollen profile?

Ole e 7 is distinct from other olive pollen allergens such as Ole e 1 (the major olive pollen allergen), Ole e 2 (profilin), Ole e 9 (glucanase), and Ole e 10. While Ole e 1 can act as an immunological marker for sensitivity against the Oleaceae family, Ole e 7 belongs to a highly conserved protein family found in both phylogenetically related and unrelated species . This conservation pattern explains its cross-reactivity potential with nsLTPs from other sources, including non-pollen allergens.

What are the recommended laboratory protocols for detecting and isolating Ole e 7?

The isolation of Ole e 7 involves a multi-step purification process. The recommended protocol includes:

• Initial extraction of olive pollen proteins

• Fractionation using gel filtration chromatography

• Further purification by reverse-phase HPLC

• Verification of allergenic fractions using immunoblotting and ELISA with sera from olive-allergic patients

This purification strategy has been validated and can serve as a model for isolating other allergens with similar properties. For detection in patient samples, specific IgE (sIgE) assays using commercial systems such as ImmunoCAP are effective, with levels >0.35 kU/L considered positive .

How can researchers characterize the molecular properties of Ole e 7 isoforms?

Molecular characterization of Ole e 7 isoforms requires several complementary techniques:

• Acid hydrolysis followed by amino acid analysis to determine composition

• Mass spectrometry for accurate molecular weight determination, especially important given the polymorphic nature of Ole e 7

• N-terminal sequencing via Edman degradation to identify sequence variations

• Recombinant production of Ole e 7 variants for structural studies and immunological comparisons

For comprehensive epitope mapping, novel immunocapture approaches coupled with liquid chromatography and high-resolution mass spectrometry have proven effective in identifying IgE-binding linear epitopes .

What functional assays are used to evaluate the biological activity of Ole e 7?

To assess the biological activity of Ole e 7 and its potential cross-reactivity:

• Basophil Activation Test (BAT): This cellular assay measures the release of mediators from basophils when stimulated with the allergen. The protocol typically uses recombinant Ole e 7 at 10 μg/mL as the stimulus, with cell staining performed using anti-human CD63 FITC/CD123 PE/HLA-DR PerCP antibody cocktail. PBS serves as a negative control and N-formyl-methionyl-leucyl-phenylalanine (fMLP) as a positive control .

• IgE-binding assays: Microplates coated with purified mouse anti-human IgE (0.2 μg/well) are used to capture IgE from patient sera. After blocking and washing steps, the plates are incubated with Ole e 7 peptides to assess binding capacity .

These functional assays provide critical information about the allergen's ability to trigger allergic responses and its cross-reactivity potential.

How is Ole e 7 sensitization associated with clinical symptoms in olive pollen allergy patients?

Ole e 7 sensitization has been significantly associated with more severe clinical manifestations of olive pollen allergy. Research indicates that patients with Ole e 7-specific IgE antibodies often experience more intense allergic responses, including anaphylactic reactions . This association with severity makes Ole e 7 sensitization an important clinical marker for risk assessment in olive pollen allergy management.

Additionally, in high-exposure areas supporting olive pollen counts over 5000 grains/m³, laboratory data show a positivity rate of 72% for Ole e 7-specific IgE , further highlighting its clinical relevance in regions with significant olive cultivation.

What methodological approaches should be used to investigate the relationship between Ole e 7 sensitization and asthma severity?

To investigate the relationship between Ole e 7 sensitization and asthma severity, researchers should employ a multifaceted approach:

• Comprehensive clinical assessment: Document detailed patient history including symptom frequency, severity, medication use, and exacerbation patterns

• Specific IgE quantification: Measure Ole e 7-specific IgE levels using standardized immunoassays

• Pulmonary function testing: Assess objective measures of airway obstruction

• Controlled exposure studies: In appropriate settings, monitor respiratory responses following controlled exposure to purified allergen components

• Longitudinal follow-up: Track asthma days and symptom severity over time

Previous studies have demonstrated that patients with Ole e 7-specific IgE antibodies experience significantly more severe bronchial asthma compared to non-sensitized individuals, with higher numbers of asthma days (comparable to findings with Ole e 10 sensitization) .

How should researchers design studies to investigate Ole e 7's role in pollen-food allergy syndrome?

When designing studies to investigate Ole e 7's role in pollen-food allergy syndrome, researchers should:

• Establish clear patient categorization: Based on sensitization profiles (e.g., monosensitized to Ole e 7, monosensitized to food LTPs like Pru p 3, or sensitized to both)

• Implement comprehensive diagnostic protocols:

  • Detailed clinical history focusing on both respiratory and food-related symptoms

  • Skin prick testing with both pollen and food allergens

  • Specific IgE quantification to relevant allergens

  • Basophil activation tests to assess cross-reactivity

• Perform controlled food challenges: Under medical supervision in appropriate cases

• Analyze geographic and environmental variables: Particularly olive pollen exposure levels

• Consider genetic factors: Such as HLA haplotyping which may influence sensitization patterns

Research has shown that anti-Ole e 7 IgE is significantly associated with fruit anaphylaxis , and in areas with high olive pollen counts, more than half of patients tested for both Ole e 7 and Pru p 3 (peach LTP) are co-sensitized .

What methodological approaches can identify cross-reactive epitopes between Ole e 7 and other nsLTPs?

To identify cross-reactive epitopes between Ole e 7 and other nsLTPs (such as Pru p 3 from peach), researchers should employ:

• Epitope mapping techniques:

  • Novel immunocapture approaches

  • Liquid chromatography coupled to high-resolution mass spectrometry

  • Peptide microarrays with overlapping synthetic peptides covering the entire sequence

• Inhibition assays:

  • ELISA inhibition using recombinant proteins

  • Immunoblot inhibition to confirm shared epitopes

• In vitro cellular assays:

  • Basophil activation tests with recombinant allergens (rOle e 7 and rPru p 3)

  • T-cell proliferation assays to assess T-cell epitope cross-recognition

A previous study found that 30% of patients sensitized to Ole e 7 without detectable sIgE to Pru p 3 showed positive BAT results when stimulated with recombinant Pru p 3, indicating potential cross-reactivity at the effector cell level despite the absence of detectable cross-reactive IgE .

How can researchers distinguish between co-sensitization and cross-reactivity to Ole e 7 and other nsLTPs?

Distinguishing between true cross-reactivity and co-sensitization requires a systematic approach:

• Sequential immunoadsorption studies:

  • Pre-adsorb patient sera with one allergen before testing reactivity to the other

  • Compare binding patterns before and after adsorption

• Recombinant allergen testing:

  • Use of purified recombinant allergens in both in vitro and in vivo tests

  • Site-directed mutagenesis of potential cross-reactive epitopes

• Epitope-specific antibody analysis:

  • Production of monoclonal antibodies against specific epitopes

  • Competitive binding assays with different nsLTPs

• Clinical correlation:

  • Compare clinical reactivity patterns with immunological findings

  • Assess symptom provocation with different allergens

Data from studies categorizing patients based on Ole e 7 and Pru p 3 sIgE profiles (monosensitized to Ole e 7, monosensitized to Pru p 3, or sensitized to both) provide a framework for such investigations .

How should researchers approach the characterization of Ole e 7 polymorphisms and their impact on allergenicity?

To characterize Ole e 7 polymorphisms and assess their impact on allergenicity, researchers should:

• Implement comprehensive protein sequencing:

  • Complete amino acid sequencing of multiple Ole e 7 isoforms

  • Mass spectrometry analysis to identify post-translational modifications

• Conduct structural biology studies:

  • X-ray crystallography or NMR spectroscopy to determine 3D structures

  • Molecular modeling to predict the impact of sequence variations on protein folding

• Perform comparative immunological testing:

  • IgE binding assays with different isoforms

  • Basophil activation tests to assess functional consequences of polymorphisms

  • T-cell epitope analysis to evaluate differences in immunological processing

• Correlate genotypic and phenotypic data:

  • Analyze the relationship between specific Ole e 7 variants and clinical manifestations

  • Investigate geographical distribution of different isoforms relative to sensitization patterns

Given that Ole e 7 exhibits a high degree of polymorphism , understanding how these variations affect allergenicity could provide important insights for diagnostic and therapeutic applications.

What experimental approaches should be used to investigate the immunological mechanisms of Ole e 7 in severe allergic reactions?

To investigate the immunological mechanisms of Ole e 7 in severe allergic reactions:

• Animal models:

  • Develop murine models sensitized to Ole e 7

  • Evaluate respiratory and systemic responses to controlled challenges

• Ex vivo human studies:

  • Analyze cytokine production profiles from peripheral blood mononuclear cells (PBMCs)

  • Assess basophil and mast cell activation thresholds using cells from sensitized patients

• Immune profiling:

  • Characterize T-cell receptor repertoires in Ole e 7-reactive lymphocytes

  • Analyze IgE affinity and avidity to Ole e 7 in patients with different clinical phenotypes

• Genetic association studies:

  • Investigate HLA associations with Ole e 7 sensitization and reaction severity

  • Examine single nucleotide polymorphisms (SNPs) in genes involved in allergic inflammation

Research has demonstrated that Ole e 7 sensitization is associated with more severe clinical symptoms in patients who have experienced anaphylactic reactions , suggesting unique immunological mechanisms that merit further investigation.

How can transcriptomic and proteomic approaches enhance our understanding of Ole e 7 expression patterns in different olive tree varieties?

Transcriptomic and proteomic approaches offer powerful tools for investigating Ole e 7 expression:

• RNA sequencing (RNA-Seq):

  • Compare Ole e 7 transcript levels across olive tree varieties

  • Analyze gene expression under different environmental conditions

  • Identify regulatory elements controlling allergen expression

• Quantitative proteomics:

  • Use isotope-coded protein labeling (ICPL) or isobaric tags for relative and absolute quantitation (iTRAQ)

  • Measure Ole e 7 protein abundance in pollen from different cultivars

  • Identify post-translational modifications that may affect allergenicity

• Single-cell analysis:

  • Characterize cell-specific expression patterns within pollen grains

  • Investigate developmental regulation of Ole e 7 production

• Environmental influence assessment:

  • Monitor Ole e 7 expression under different climate conditions

  • Evaluate the impact of pollution, temperature, and humidity on allergen expression

These advanced approaches could help explain the observed variations in Ole e 7 prevalence among different geographical populations and potentially identify olive varieties with reduced allergenic potential for future agricultural considerations.