Anaphylaxis to insect venom allergens: role of molecular diagnostics

Bee Venom Toxic Effect on MDA-MB-231 Breast Cancer Cells and Caenorhabditis Elegans

INTRODUCTION

Bee venom has therapeutics and pharmacological properties. Further toxicological studies on animal models are necessary due to the severe allergic reactions caused by this product.

METHOD

Here, Caenorhabditis elegans was used as an in vivo toxicity model, while breast cancer cells were used to evaluate the pharmacological benefits. The bee venom utilized in this research was collected from Apis mellifera species found in Northeast Brazil. The cytotoxicity caused by bee venom was measured by MTT assay on MDA-MB-231 and J774 A.1 cells during 24 - 72 hours of exposure. C. elegans at the L4 larval stage were exposed for three hours to M9 buffer or bee venom. Survival, behavioral parameters, reproduction, DAF-16 transcription factor translocation, the expression of superoxide dismutase (SOD), and metabolomics were analyzed. Bee venom suppressed the growth of MDA-MB-231 cancer cells and exhibited cytotoxic effects on macrophages. Also, decreased C. elegans survival impacted its behaviors by decreasing C. elegans feeding behavior, movement, and reproduction.

RESULTS

Bee venom did not increase the expression of SOD-3, but it enhanced DAF-16 translocation from the cytoplasm to the nucleus. C. elegans metabolites differed after bee venom exposure, primarily related to aminoacyl- tRNA biosynthesis, glycine, serine and threonine metabolism, and sphingolipid and purine metabolic pathways. Our findings indicate that exposure to bee venom resulted in harmful effects on the cells and animal models examined.

CONCLUSION

Thus, due to its potential toxic effect and induction of allergic reactions, using bee venom as a therapeutic approach has been limited. The development of controlled-release drug strategies to improve this natural product's efficacy and safety should be intensified.

Structural Similarities, in Relation with the Cross-Reactivity, of Hymenoptera Allergenic Dipeptidyl Peptidases IV-An Overall Comparison Including a New Dipeptidyl Peptidase IV Sequence from Vespa velutina

(1) Background: Dipeptidyl Peptidases IV (DPPIVs), present in many organisms, are minor components in the venoms of Hymenoptera, where they have been identified as cross-reactive allergenic molecules. Considering that the structure of homologous DPPIVs is well characterized, we aimed to explain which regions have higher similarity among these proteins and present a comparison among them, including a new Vespa velutina DPPIV sequence. Moreover, two cases of sensitization to DPPIVs in wasp- and honeybee-sensitized patients are presented. (2) Methods: Proteomic analyses have been performed on the venom of the Asian hornet Vespa velutina to demonstrate the sequence of its DPPIV (allergen named Vesp v 3, with sequence accession number P0DRB8, and with the proteomic data available via ProteomeXchange with the identifier PXD046030). A comparison performed through their alignments and analysis of the three-dimensional structure showed a region with higher similarity among Hymenoptera DPPIVs. Additionally, ImmunoCAP™ determinations (including specific inhibition experiments), as well as IgE immunoblotting, are performed to demonstrate the allergenicity of Api m 5 and Ves v 3. (3) Results and Conclusions: The data presented demonstrate that the similarities among Hymenoptera DPPIVs are most likely localized at the C-terminal region of these enzymes. In addition, a higher similarity of the Vespa/Vespula DPPIVs is shown. The clinical cases analyzed demonstrated the allergenicity of Api m 5 and Ves v 3 in the sera of the allergic patients, as well as the presence of this minor component in the preparations used in venom immunotherapy.

Recombinant antigen 5 from Polybia paulista wasp venom (Hymenoptera, Vespidae): Antigen-specific antibody production and functional profile of CD4+ T cells in the immune response

Polybia paulista is a neotropical social wasp related to severe accidents and allergic reactions cases, including anaphylaxis, in southeastern Brazil. Antigen 5 (Poly p 5) is a major allergenic protein from its venom with potential use for component-resolved diagnostic. Therefore, the previous characterization of the immune response profile triggered by Poly p 5 should be evaluated. Recombinant Poly p 5 (rPoly p 5) was used to sensitize BALB/c mice with six weekly intradermal doses, and the specific antibody production and the functional profile of CD4+ T cells were assessed. rPoly p 5 induced the production of specific immunoglobulins (sIg) sIgE, sIgG1 and sIgG2a, which could recognize natural Poly p 5 presented in the venom of four different wasp species. rPoly p 5 stimulated in vitro the CD4+ T cells from immunized mice, which showed a significant proliferative response. These antigen-specific CD4+T cells produced IFN-γ and IL-17A cytokines and increased ROR-γT transcription factor expression. No differences between the control group and sensitized mice were found in IL-4 production and GATA-3 and T-bet expression. Interestingly, increased CD25+FoxP3+ regulatory T cells (Tregs) frequency was observed in the splenocyte cell cultures from rPoly p 5 immunized mice after the in vitro stimulation with both P. paulista venom extract and rPoly p 5. Here we showed that rPoly p 5 induces antigen-specific antibodies capable of recognizing Antigen 5 in the venom of four wasp species and modulates antigen-specific CD4+ T cells to IFN-γ production response associated with a Th17 profile in sensitized mice. These findings emphasize the potential use of rPoly p 5 as an essential source of a major wasp allergen with significant immunological properties.

Severe pathological changes in the blood and organs of SD rats stung by honeybees

With the development of beekeeping, the risk of bee stings in humans is increasing. Severe and life-threatening toxic reactions can occur after multiple bee stings, and their pathogenesis has not been elucidated. To understand the effect of multiple bees (Apis mellifera) stings on the organism in a short period, we stung rats once and five times, respectively. Serum and organs were obtained after 3 h for analysis. The results indicated that skin erythema was more pronounced and hemolysis was more severe as the number of puncture wounds increased. After being stung by five bees, rats had dramatically higher serum levels of direct bilirubin, aspartate aminotransferase, creatine kinase and lactate dehydrogenase, producing more differential metabolites that affected mainly four metabolic pathways. In addition, the liver, kidney and heart showed significant congestion and inflammation. This study helps explain the organism's clinical response to bee venom and may be valuable in treating toxic reactions following bee stings.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Diagnosis of Hymenoptera Venom Allergy: State of the Art, Challenges, and Perspectives

Hymenoptera venom allergy is the most common cause of anaphylaxis in adults and the second-most frequent in children. The proper diagnosis of this life-threatening allergy remains a challenge. This review focuses on the current knowledge regarding diagnostics of Hymenoptera venom allergy. The paper includes a brief description of the representatives of Hymenoptera order and the composition of their venoms. Then, diagnostic tests for allergy to Hymenoptera venom are described. Common diagnostic problems, especially double positivity in tests for IgE antibodies specific to honeybee and wasp venom, are also discussed. Special attention is paid to the search for new diagnostic capabilities using modern methodologies. Multidimensional molecular analysis offers an opportunity to characterize changes in body fluids associated with Hymenoptera venom allergy and yields a unique insight into the cell status. Despite recent developments in the diagnostics of Hymenoptera venom allergy, new testing methodologies are still needed to answer questions and doubts we have.

Basophil activation test as alternative method to CAP-inhibition in patients with double sensitization to vespid venoms

Most patients with Hymenoptera venom allergy (HVA) to vespid venoms present double sensitization by specific IgE (sIgE)-mediated cross-reactivity. Thus, it is mandatory could discriminate between a true double and primary sensitization to implement an accurate venom-specific immunotherapy (VIT). To date, CAP-inhibition is the reference method in the diagnosis of cross-reactivity in double sensitized patients to vespid venoms, being the results obtained with the component resolved diagnostics (CRD) conflicting. For this, we have studied in a cohort of double sensitized patients to Vespula vulgaris (VV) and Polistes dominulus (PD) venoms (n = 40) the diagnostic accuracy of CRD using the CAP-inhibition as reference method, as well as to investigate whether basophil activation test (BAT) is an alternative method for inconclusive results obtained by CAP-inhibition. CAP-inhibition showed a sensitivity of 59.46 % in view of the indeterminate results; most patients had true double sensitization (54.5 %), followed by single sensitization to PD (27.27 %) and VV (18.18 %) venoms. CRD based on rVes v 5/rPol d 5 (or vice versa) ratio as well as whole extracts I3/I77 (or vice versa) ratio (specific IgE-I3 to VV/specific IgE-I77 to PD) showed a low diagnostic accuracy (AUC = 0.504, p = 0.974; AUC = 0.35, p = 0.235; respectively). BAT was determined in parallel with CAP-inhibition in 12 patients, presented higher sensitivity than CAP-inhibition (p = 0.021) and a positive agreement of 71.43 %. Likewise it was able to identify 100% of inconclusive results, showing a specificity of 83.3 %. Therefore, CRD is not a suitable method to distinguish monosensitization and BAT appears to be an appropriate method resolving indeterminate results from the gold standard method.

Profiling hymenopteran venom toxins: Protein families, structural landscape, biological activities, and pharmacological benefits

Hymenopterans are an untapped source of venom secretions. Their recent proteo-transcriptomic studies have revealed an extraordinary pool of toxins that participate in various biological processes, including pain, paralysis, allergic reactions, and antimicrobial activities. Comprehensive and clade-specific campaigns to collect hymenopteran venoms are therefore needed. We consider that data-driven bioprospecting may help prioritise sampling and alleviate associated costs. This work established the current protein landscape from hymenopteran venoms to evaluate possible sample bias by studying their origins, sequence diversity, known structures, and biological functions. We collected all 282 reported hymenopteran toxins (peptides and proteins) from the UniProt database that we clustered into 21 protein families from the three studied clades - wasps, bees, and ants. We identified 119 biological targets of hymenopteran toxins ranging from pathogen membranes to eukaryotic proteases, ion channels and protein receptors. Our systematic study further extended to hymenopteran toxins' therapeutic and biotechnological values, where we revealed promising applications in crop pests, human infections, autoimmune diseases, and neurodegenerative disorders.

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The hymenopteran toxin diversity includes 21 protein families from 81 species.

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Some toxins are shared across wasps, bees and ants, others are clade-specific.

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Their venoms contain membrane-active peptides, neurotoxins, allergens and enzymes.

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Hymenopteran toxins have been tested against a total of 119 biological targets.

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Hymenopteran toxins were predominantly evaluated as anti-infective agents.

Component-Resolved Evaluation of the Risk and Success of Immunotherapy in Bee Venom Allergic Patients

Venom immunotherapy (VIT) is the only efficient therapy for the Hymenoptera insect venom allergy. Immunotherapy with bee venom is encumbered with a higher risk of systemic side effects and/or therapeutic failures. The objective of the study was to assess if specific profiles of molecular IgE (Immunoglobulin E) responses are associated with an increased risk of systemic side effects and/or the treatment’s inefficacy. The study group numbered 64 bee venom allergic patients (BVA) who received venom immunotherapy modo ultra-rush (VIT-UR), (f/m: 32/32, mean age 43.4 ± 17.2). In total, 54.84% of them manifested allergic reactions of grades I-III (acc. to Mueller’s scale), while 48.66% manifested reactions of grade IV. In all the patients, IgE against bee venom extract, rApi m 1 and tryptase (sBT) were assessed. In 46 patients, assessments of IgE against rApi m 2, 3, 5, 10 were also performed. BVA patients manifesting cardiovascular symptoms (SYS IV0) showed higher levels of both sIgE-rApi m 5 (p = 0.03) and tryptase (p = 0.07) than patients with SYS I−III. Systemic adverse events during VIT with bee venom were more frequent in the induction phase than in the maintenance phase: 15.22% vs. 8.7%. In BVA patients who experienced systemic adverse events during VIT, higher concentrations of sIgE-rApi m 5 (p < 0.05), rApi m 1 (p = 0.009), and sBT (p = 0.019) were demonstrated. We conclude that higher levels of sIgE against rApi m 1, rApi m 5, and tryptase many constitute a potential marker of the severity of allergic reactions and therapeutic complications that can occur during VIT with bee venom.

Venom Immunotherapy: From Proteins to Product to Patient Protection

In this review, we outline and reflect on the important differences between allergen-specific immunotherapy for inhalant allergies (i.e., aeroallergens) and venom-specific immunotherapy (VIT), with a special focus on Venomil® Bee and Wasp. Venomil® is provided as a freeze-dried extract and a diluent to prepare a solution for injection for the treatment of patients with IgE-mediated allergies to bee and/or wasp venom and for evaluating the degree of sensitivity in a skin test. While the materials that make up the product have not changed, the suppliers of raw materials have changed over the years. Here, we consolidate relevant historical safety and efficacy studies that used products from shared manufacture supply profiles, i.e., products from Bayer or Hollister-Stier. We also consider the characterization and standardization of venom marker allergens, providing insights into manufacturing controls that have produced stable and consistent quality profiles over many years. Quality differences between products and their impacts on treatment outcomes have been a current topic of discussion and further research. Finally, we review the considerations surrounding the choice of depot adjuvant most suitable to augmenting VIT.

The role of component-resolved diagnosis in Hymenoptera venom allergy in clinical practice

Background: Hymenoptera venom allergy is an immunoglobulin (Ig) E mediated hypersensitivity reaction to Hymenoptera venoms. Obvious identification of the culprit insect that causes the clinical symptoms and, hence, the accurate selection of venom for curative treatment, is of great importance for the effectiveness and safety of venom immunotherapy. Objective: In this study, the contribution of component-resolved diagnostics (CRD) is evaluated in the diagnosis of Hymenoptera venom allergy. Method: Ninety-three patients from four different centers in Turkey were included in the study. Conventional tests, including prick and intradermal skin tests, with commercial venom extracts and serum specific IgE (sIgE) levels for whole venoms were performed. An sIgE analysis for venom allergen components, including rApi m 1, rApi m 2, rApi m 10, rVes v 1, rVes v 5, were evaluated by immunoblotting. Results: In conventional test results, 17 of 35 patients with bee venom allergy were positive to honey bee venom, whereas 18 patients were positive to bee and wasp venoms. In 28 of 35 patients with bee venom allergy, the diagnosis was confirmed with CRD. CRD revealed a sensitivity of 80% in patients with bee venom allergy. According to conventional tests, 7 of 24 patients with vespid venom allergy demonstrated sensitivity only to Vespula species, whereas 17 patients revealed double positivity. The total diagnostic sensitivity of Ves v 1 and Ves v 5 was calculated as 87.5%. Ten of 23 patients with a history of hypersensitivity to both venoms showed double sensitivity with CRD; one patient had cross-reactivity, one patient was found to be sensitive only to bee venom, and, eight patients were sensitive only to Vespula species. Eleven patients had an uncertain history in terms of the culprit insect type and six of them had double sensitivity in CRD. Conclusion: CRD seemed to be more helpful in diagnosing vespid venom allergy than bee venom allergy. It can also discriminate clinically significant sensitizations from irrelevant ones.

Immunological Responses to Envenomation

Venoms are complex mixtures of toxic compounds delivered by bite or sting. In humans, the consequences of envenomation range from self-limiting to lethal. Critical host defence against envenomation comprises innate and adaptive immune strategies targeted towards venom detection, neutralisation, detoxification, and symptom resolution. In some instances, venoms mediate immune dysregulation that contributes to symptom severity. This review details the involvement of immune cell subtypes and mediators, particularly of the dermis, in host resistance and venom-induced immunopathology. We further discuss established venom-associated immunopathology, including allergy and systemic inflammation, and investigate Irukandji syndrome as a potential systemic inflammatory response. Finally, this review characterises venom-derived compounds as a source of immune modulating drugs for treatment of disease.

New Biomarkers of Hymenoptera Venom Allergy in a Group of Inflammation Factors

Hymenoptera venom allergy significantly affects the quality of life. Due to the divergences in the results of the available test and clinical symptoms of patients, the current widely applied diagnostic methods are often insufficient to classify patients for venom immunotherapy (VIT). Therefore it is still needed to search for new, more precise, and accurate diagnostic methods. Hence, this research aimed to discover new biomarkers of Hymenoptera venom allergy in a group of inflammation factors using set of multi-marker Bioplex panel. The adoption of a novel methodology based on Luminex/xMAP enabled simultaneous determination of serum levels of 37 different inflammatory proteins in one experiment. The study involved 21 patients allergic to wasp and/or honey bee venom and 42 healthy participants. According to univariate and multivariate statistics, soluble CD30/tumor necrosis factor receptor superfamily, member 8 (sCD30/TNFRSF8), and the soluble tumor necrosis factor receptor 1 (sTNF-R1) may be considered as effective prognostic factors, their circulating levels were significantly decreased in the allergy group (p-value < 0.05; the Area Under the Curve (AUC) ~0.7; Variable Importance in Projection (VIP) scores >1.2). The obtained results shed new light on the allergic inflammatory response and may contribute to modification and improvement of the diagnostic and monitoring methods. Further, large-scale studies are still needed to explain mechanisms of action of studied compounds and to definitively prove their usefulness in clinical practice.

Omalizumab ensures compatibility to bee venom immunotherapy (VIT) after VIT-induced anaphylaxis in a patient with systemic mastocytosis

Background: Systemic reactions and anaphylaxis due to Hymenoptera venoms occur in up to 7.5% of the European population. Fatal sting reactions are very rare. Serum tryptase levels should be measured in all patients with a history of severe reactions in order to detect mastocytosis and to determine the risk of severe reactions to venom immunotherapy (VIT). The risk to experience severe or even fatal anaphylaxis due to insect stings is quite high in patients with mastocytosis. Therefore, lifelong VIT is recommended in these highly threatened patients. Multicenter studies involving a large population report that up to 20% of patients undergoing VIT have intolerance and systemic reactions to immunotherapy. Some of these side effects occur repeatedly and cannot be managed by standard treatment. A pre-treatment with the anti-IgE antibody omalizumab was useful in many cases. However, omalizumab is not approved for the indication anaphylaxis. Therefore, there is still no defined protocol for omalizumab pre-treatment, and the optimal duration, dosage as well as long-time benefits are still unclear. Case report: We present a 60-year-old female patient with mastocytosis who developed a severe anaphylactic reaction during initiation of bee VIT. Serum tryptase was elevated, and a KIT mutation D816V was subsequently confirmed. Component-resolved diagnostic tests revealed specific IgE antibodies to recombinant Api m 1 only. The patient was treated with 150 mg omalizumab, administered subcutaneously 5 weeks, 3 weeks, and 1 week prior to re-start of immunotherapy and for 2 months in parallel to VIT. Updosing was done by a 7-day rush schedule. During this period, no anaphylactic reaction developed, and the bee VIT was well tolerated with up to 200 µg bee venom. The patient is currently in the 3^rd year of treatment and tolerates the treatment very well. Conclusion: Omalizumab may be used as a premedication in patients with mastocytosis who do not tolerate VIT. Although there is no consensus on the treatment protocol, treatment for 2 – 6 months is considered adequate. The long-term benefits of such treatment require further research.

CpG Adjuvant in Allergen-Specific Immunotherapy: Finding the Sweet Spot for the Induction of Immune Tolerance

Prevalence and incidence of IgE-mediated allergic diseases have increased over the past years in developed and developing countries. Allergen-specific immunotherapy (AIT) is currently the only curative treatment available for allergic diseases that has long-term efficacy. Although AIT has been proven successful as an immunomodulatory therapy since its beginnings, it still faces several unmet needs and challenges today. For instance, some patients can experience severe side effects, others are non-responders, and prolonged treatment schedules can lead to lack of patient adherence and therapy discontinuation. A common strategy to improve AIT relies on the use of adjuvants and immune modulators to boost its effects and improve its safety. Among the adjuvants tested for their clinical efficacy, CpG oligodeoxynucleotide (CpG-ODN) was investigated with limited success and without reaching phase III trials for clinical allergy treatment. However, recently discovered immune tolerance-promoting properties of CpG-ODN place this adjuvant again in a prominent position as an immune modulator for the treatment of allergic diseases. Indeed, it has been shown that the CpG-ODN dose and concentration are crucial in promoting immune regulation through the recruitment of pDCs. While low doses induce an inflammatory response, high doses of CpG-ODN trigger a tolerogenic response that can reverse a pre-established allergic milieu. Consistently, CpG-ODN has also been found to stimulate IL-10 producing B cells, so-called B regulatory cells (Bregs). Accordingly, CpG-ODN has shown its capacity to prevent and revert allergic reactions in several animal models showing its potential as both preventive and active treatment for IgE-mediated allergy. In this review, we describe how CpG-ODN-based therapies for allergic diseases, despite having shown limited success in the past, can still be exploited further as an adjuvant or immune modulator in the context of AIT and deserves additional attention. Here, we discuss the past and current knowledge, which highlights CpG-ODN as a potential adjuvant to be reevaluated for the enhancement of AIT when used in appropriate conditions and formulations.

In silico analysis of cross reactivity among phospholipases from Hymenoptera species

Background: Phospholipases are enzymes with the capacity to hydrolyze membrane lipids and have been characterized in several allergenic sources, such as hymenoptera species. However, cross-reactivity among phospholipases allergens are little understood. The objective of this study was to determine potential antigenic regions involved in cross-reactivity among allergens of phospholipases using an in silico approach.

Methods: In total, 18 amino acids sequences belonging to phospholipase family derived from species of the order hymenoptera were retrieved from the UniProt database to perform phylogenetic analysis to determine the closest molecular relationship. Multialignment was done to identify conserved regions and matched with antigenic regions predicted by ElliPro server. 3D models were obtained from modeling by homology and were used to locate cross-reactive antigenic regions.

Results: Phylogenetic analysis showed that the 18 phospholipases split into four monophyletic clades (named here as A, B, C and D). Phospholipases from A clade shared an amino acid sequences’ identity of 79%. Antigenic patches predicted by Ellipro were located in highly conserved regions, suggesting that they could be involved in cross-reactivity in this group (Ves v 1, Ves a 1 and Ves m 1).

Conclusions: At this point, we advanced to the characterization of potential antigenic sites involved in cross-reactivity among phospholipases. Inhibition assays are needed to confirm our finding.

Precision Medicine in Hymenoptera Venom Allergy: Diagnostics, Biomarkers, and Therapy of Different Endotypes and Phenotypes

Allergic reactions to stings of Hymenoptera species may be severe and are potentially fatal deviations of the immunological response observed in healthy individuals. However, venom-specific immunotherapy (VIT) is an immunomodulatory approach able to cure venom allergy in the majority of affected patients. An appropriate therapeutic intervention and the efficacy of VIT not only depend on a conclusive diagnosis, but might also be influenced by the patient-specific manifestation of the disease. As with other diseases, it should be borne in mind that there are different endotypes and phenotypes of venom allergy, each of which require a patient-tailored disease management and treatment scheme. Reviewed here are different endotypes of sting reactions such as IgE-mediated allergy, asymptomatic sensitization or a simultaneous presence of venom allergy and mast cell disorders including particular considerations for diagnosis and therapy. Additionally, phenotypical manifestations of venom allergy, as e.g. differences in age of onset and disease severity, multiple sensitization or patients unsusceptible to therapy, are described. Moreover, biomarkers and diagnostic strategies that might reflect the immunological status of the patient and their value for therapeutic guidance are discussed. Taken together, the increasing knowledge of different disease manifestations in venom hypersensitivity and the growing availability of diagnostic tools open new options for the classification of venom allergy and, hence, for personalized medical approaches and precision medicine in Hymenoptera venom allergy.

The role of component-resolved diagnosis in Hymenoptera venom allergy

PURPOSE OF REVIEW

Component-resolved diagnostics (CRD) is a new tool aiming at detecting IgE-mediated sensitizations against individual, relevant allergens. Here, we discuss recent literature on molecular diagnosis in the field of Hymenoptera venom allergy (HVA) as well as CRD strengths and weaknesses.

RECENT FINDINGS

CRD, using single molecules or panels of allergens, may discriminate between primary sensitization and cross-reactivity in patients with double/multiple positivity in diagnostic tests with whole extracts, allowing the specialist to choose the most suitable venom for specific immunotherapy (VIT), avoiding unnecessary VIT and reducing the risk of side effects. Future availability of the cross-reactive recombinant pairs of allergens of different species may further increase the diagnostic performance. CRD may be useful in patients with negative allergy tests and a proven history of a previous systemic reaction, including those with mast cell disorders, who could benefit from VIT. In honeybee venom allergy, different sensitization profiles have been identified, which could be associated with a greater risk of VIT failure or treatment side effects.

SUMMARY

CRD is undoubtedly an innovative diagnostic method that leads to a more precise definition of the sensitization profile of the HVA patient. Together with a better knowledge of the molecular composition of different venom extracts, CRD may contribute to optimize patient-tailored therapy.

Antigen 5 Allergens of Hymenoptera Venoms and Their Role in Diagnosis and Therapy of Venom Allergy

PURPOSE OF REVIEW

Stings of Hymenoptera of the superfamily Vespoidea such as yellow jackets, paper wasps or stinging ants are common triggers for severe and even fatal allergic reactions. Antigen 5 allergens are potent allergens in the majority of these venoms with major importance for diagnosis and therapy. Reviewed here are the characteristics of antigen 5 allergens, their role in component-resolved diagnostics as well as current limitations of the available diagnostics for proper therapeutic decisions.

RECENT FINDINGS

Antigens 5 are proteins of unknown function in Hymenoptera venoms with high allergenic potency. They represent key elements in component-resolved diagnosis to discriminate between honeybee and vespid venom allergy. However, due to their pronounced cross-reactivity, there are remaining diagnostic and therapeutic challenges that have to be addressed. Antigens 5 are highly relevant venom allergens of the Vespoidea superfamily. Although their use in component-resolved diagnosis facilitates dissection of cross-reactivity and primary allergy in double sensitization to honeybee and vespid venom, new diagnostic concepts are needed to discriminate between allergies to different vespid species.

Shedding Light on the Venom Proteomes of the Allergy-Relevant Hymenoptera Polistes dominula (European Paper Wasp) and Vespula spp. (Yellow Jacket)

Allergic reactions to stings of Hymenoptera species can have serious or even fatal consequences. If the identification of the culprit insect is possible, venom-specific immunotherapy effectively cures Hymenoptera venom allergies. Although component-resolved diagnostics has strongly evolved in recent years, the differentiation between allergies to closely related species such as Polistes dominula and Vespula spp. is still challenging. In order to generate the basis for new diagnostic and therapeutic strategies, this study aims at resolving the venom proteomes (venomes) of these species. The venoms of P. dominula and Vespula spp. (V. germanica, V. vulgaris) were analyzed by liquid chromatography-mass spectrometry. Resulting proteins were characterized regarding their function, localization and biochemical properties. The analyses yielded 157 proteins in Vespula spp. and 100 in P. dominula venom; 48 proteins, including annotated allergens, were found in both samples. In addition to a variety of venom trace molecules, new allergen candidates such as icarapin-like protein and phospholipase A2 were identified. This study elucidates the venomes of closely related allergy-eliciting Hymenoptera species. The data indicates that relying on marker allergens to differentiate between P. dominula and Vespula spp. venom allergy is probably insufficient and that strategies using cross-reactive major allergens could be more promising.

Improved production of the recombinant phospholipase A1 from Polybia paulista wasp venom expressed in bacterial cells for use in routine diagnostics

Phospholipase A1 (PLA1) is one of the three major allergens identified in the venom of P. paulista (Hymenoptera: Vespidae), a clinically relevant wasp from southeastern Brazil. The recombinant form of this allergen (rPoly p 1) could be used for the development of molecular diagnostic of venom allergy. Early attempts to produce rPoly p 1 using Escherichia coli BL21 (DE3) cells rendered high yields of the insoluble rPoly p 1 but with low levels of solubilized protein recovery (12%). Here, we aimed to improve the production of rPoly p 1 in E. coli by testing different conditions of expression, solubilization of the inclusion bodies and protein purification. The results showed that the expression at 16 °C and 0.1 mM of IPTG increased the production of rPoly p 1, still in the insoluble form, but with high solubilized protein yields after incubation with citrate-phosphate buffer with 0.15 M NaCl, 6 M urea, pH 2.6 at 25 ºC for 2 h. The venom allergen was also cloned in pPICZαA vector for soluble expression as a secreted protein in Pichia pastoris X-33 cells, rendering almost undetectable levels (nanograms) in the culture supernatant. In contrast, a sevenfold increase of the solubilized and purified rPoly p 1 yields (1.5 g/L of fermentation broth) was obtained after improved production in E. coli. The identity of the protein was confirmed with an anti-His antibody and MS spectra. Allergen-specific IgE (sIgE)-mediated recognition was evaluated in immunoblotting with sera of allergic patients (n = 40). Moreover, rPoly p 1 showed high levels of diagnostic sensitivity (95%). The optimized strategy for rPoly p 1 production described here, will provide the amounts of allergen necessary for the subsequent protein refolding, immunological characterization steps, and ultimately, to the development of molecular diagnostic for P. paulista venom allergy.

Apitoxin and Its Components against Cancer, Neurodegeneration and Rheumatoid Arthritis: Limitations and Possibilities

Natural products represent important sources for the discovery and design of novel drugs. Bee venom and its isolated components have been intensively studied with respect to their potential to counteract or ameliorate diverse human diseases. Despite extensive research and significant advances in recent years, multifactorial diseases such as cancer, rheumatoid arthritis and neurodegenerative diseases remain major healthcare issues at present. Although pure bee venom, apitoxin, is mostly described to mediate anti-inflammatory, anti-arthritic and neuroprotective effects, its primary component melittin may represent an anticancer therapeutic. In this review, we approach the possibilities and limitations of apitoxin and its components in the treatment of these multifactorial diseases. We further discuss the observed unspecific cytotoxicity of melittin that strongly restricts its therapeutic use and review interesting possibilities of a beneficial use by selectively targeting melittin to cancer cells.

Expression of eosinophils, RANTES and IL-25 in the first phase of Hymenoptera venom immunotherapy

Introduction

Venom immunotherapy (VIT) can protect against severe anaphylactic reactions (SR) in 80–100% of subjects allergic to Hymenoptera venom. The mechanisms of induction of immunological tolerance produced by VIT are still little known. It has been shown that VIT modulates Treg activity, Th2 or Th1 cells or both, increases production of IL-10, decreases secretion of IL-13, and causes an IgG4/IgE ratio shift.

Aim

To investigate the blood eosinophil count, CCL5/RANTES and IL-17E/IL-25 concentrations before and after the initial phases of the rush protocol of VIT.

Material and methods

Forty individuals (14 males, 26 females) of mean age 41.03 ±12.43 years were included in the study. The peripheral eosinophils and the concentration of serum interleukin IL-17E/IL-25 and RANTES were determined before and after the initial phase of VIT.

Results

Paired sample t-test revealed that all patients after VIT had significantly higher eosinophil levels compared to the baseline (mean: 0.42 vs. 0.64, p < 0.05). Moreover, in subjects treated with bee venom, RANTES levels proved to rise significantly (51 × 103 vs. 62 × 103, p < 0.05) while IL-17E/IL-25 dropped with near-marginal significance (916 vs. 650, p = 0.069).

Conclusions

Our immunological study on the early phase of venom immunotherapy suggested that eosinophils, cytokines such as CCL5/RANTES and IL-17E/IL-25 contribute to the immunological response.

Revisiting Polybia paulista wasp venom using shotgun proteomics - Insights into the N-linked glycosylated venom proteins

The partial proteome of Polybia paulista wasp venom was previously reported elsewhere using a gel-dependent approach and resulted in the identification of a limited number of venom toxins. Here, we reinvestigated the P. paulista venom using a gel-free shotgun proteomic approach; the highly dynamic range of this approach facilitated the detection and identification of 1673 proteins, of which 23 venom proteins presented N-linked glycosylation as a posttranslational modification. Three different molecular forms of PLA1 were identified as allergenic proteins, and two of these forms were modified by N-linked glycosylation. This study reveals an extensive repertoire of hitherto undescribed proteins that were classified into the following six different functional groups: (i) typical venom proteins; (ii) proteins related to the folding/conformation and PTMs of toxins; (iii) proteins that protect toxins from oxidative stress; (iv) proteins involved in chemical communication; (v) housekeeping proteins; and (vi) uncharacterized proteins. It was possible to identify venom toxin-like proteins that are commonly reported in other animal venoms, including arthropods such as spiders and scorpions. Thus, the findings reported here may contribute to improving our understanding of the composition of P. paulista venom, its envenoming mechanism and the pathologies experienced by the victim after the wasp stinging accident. BIOLOGICAL SIGNIFICANCE: The present study significantly expanded the number of proteins identified in P. paulista venom, contributing to improvements in our understanding of the envenoming mechanism produced by sting accidents caused by this wasp. For example, novel wasp venom neurotoxins have been identified, but no studies have assessed the presence of this type of toxin in social wasp venoms. In addition, 23 N-linked glycosylated venom proteins were identified in the P. paulista venom proteome, and some of these proteins might be relevant allergens that are immunoreactive to human IgE.

Insect venom phospholipases A1 and A2: Roles in the envenoming process and allergy

Insect venom phospholipases have been identified in nearly all clinically relevant social Hymenoptera, including bees, wasps and ants. Among other biological roles, during the envenoming process these enzymes cause the disruption of cellular membranes and induce hypersensitive reactions, including life threatening anaphylaxis. While phospholipase A2 (PLA2) is a predominant component of bee venoms, phospholipase A1 (PLA1) is highly abundant in wasps and ants. The pronounced prevalence of IgE-mediated reactivity to these allergens in sensitized patients emphasizes their important role as major elicitors of Hymenoptera venom allergy (HVA). PLA1 and -A2 represent valuable marker allergens for differentiation of genuine sensitizations to bee and/or wasp venoms from cross-reactivity. Moreover, in massive attacks, insect venom phospholipases often cause several pathologies that can lead to fatalities. This review summarizes the available data related to structure, model of enzymatic activity and pathophysiological roles during envenoming process of insect venom phospholipases A1 and -A2.

Component-resolved diagnosis in selecting patients for yellowjacket venom immunotherapy

BACKGROUND

Venom immunotherapy is effective in preventing systemic allergic reactions (SARs), but the diagnosis of venom allergy is problematic.

OBJECTIVE

To compare the performance of component-resolved diagnosis and conventional tests in patients referred for venom immunotherapy.

METHODS

We measured serum-specific immunoglobulin E to yellowjacket and honeybee venoms (Ves v 1 and Ves v 5 and Api m 1), cross-reactive carbohydrate determinants, serum basal tryptase (ImmunoCAP, ThermoFisher Scientific, Uppsala, Sweden), and skin prick test reactions in 84 patients referred to receive venom immunotherapy. History of SAR and its severity were evaluated.

RESULTS

Of the 78 patients with suspected yellowjacket venom (YJV) allergy, a history of SAR was confirmed in 47 (60%) and 31 (40%) had a non-SAR reaction. The most accurate tests to confirm venom allergy after a SAR were serum-specific immunoglobulin E to yellowjacket whole-venom extract spiked with Ves v 5 (area under the curve 0.87, 95% confidence interval 0.77-0.97, P < .001) and Ves v 5 (area under the curve 0.86, 95% confidence interval 0.76-0.96, P < .001). Sensitization to Ves v 1 was infrequent and its area under the curve was low (0.62, 95% confidence interval 0.47-0.76, P = .106). Sensitivity of the YJV skin prick test was 86%, but its specificity was low at 54%. Double sensitization to yellowjacket and honeybee occurred frequently in skin prick tests. Of the patients without a SAR, 26% showed a positive reaction to YJV in any serum test and 46% showed a positive reaction in skin tests.

CONCLUSION

Specific immunoglobulin E to the YJV spiked with Ves v 5 confirmed the allergy after a SAR. A history of SAR should be confirmed before testing, because venom sensitization is frequent in other types of reactions.

Immunology of Bee Venom

Bee venom is a blend of biochemicals ranging from small peptides and enzymes to biogenic amines. It is capable of triggering severe immunologic reactions owing to its allergenic fraction. Venom components are presented to the T cells by antigen-presenting cells within the skin. These Th2 type T cells then release IL-4 and IL-13 which subsequently direct B cells to class switch to production of IgE. Generating venom-specific IgE and crosslinking FcεR1(s) on the surface of mast cells complete the sensitizing stage in allergic individuals who are most likely to experience severe and even fatal allergic reactions after being stung. Specific IgE for bee venom is a double-edged sword as it is a powerful mediator in triggering allergic events but is also applied successfully in diagnosis of the venom allergic patient. The healing capacity of bee venom has been rediscovered under laboratory-controlled conditions using animal models and cell cultures. The potential role of enzymatic fraction of bee venom including phospholipase A2 in the initiation and development of immune responses also has been studied in numerous research settings. Undoubtedly, having insights into immunologic interactions between bee venom components and innate/specific immune cells both locally and systematically will contribute to the development of immunologic strategies in specific and epitope-based immunotherapy especially in individuals with Hymenoptera venom allergy.

A twenty-two-year experience with Hymenoptera venom immunotherapy in a US pediatric tertiary care center 1996-2018

BACKGROUND

The rate of systemic reactions (SRs) to venom immunotherapy (VIT) in children has not been well evaluated.

OBJECTIVE

To evaluate the rate of SRs to VIT in pediatric patients age 5 to 18 years who were treated with a standard protocol.

METHODS

A retrospective chart review was conducted to identify patients who received VIT at Boston Children's Hospital from 1996 through 2018. Information on venom testing, severity of reaction to insect field sting, and SRs to VIT were retrieved.

RESULTS

A total of 78 patients were included. Most had moderate to severe reactions to insect sting before VIT. The rate of SRs was 0.2% of injection visits, occurring in 9% of patients. The SRs from VIT were mild (mostly grade 1 and some grade 2), and no grades 3, 4, or 5 reactions were seen. Male sex was a significant risk factor for moderate to severe reactions to insect sting. Positive testing to vespinae was seen in 98.7% of patients, and none had exclusive sensitivity to honeybee. The severity of the initial, pre-VIT insect sting reactions in our patients did not correlate with the occurrence of SRs from VIT. Twenty-seven percent of the patients were subsequently stung while on VIT. Only 1 patient (5%) had a mild SR, while all others had only local or no reaction at all.

CONCLUSION

In the largest US study evaluating the safety of VIT in children, SRs to VIT were mild, and none required epinephrine. Male sex was significantly associated with higher risk of moderate to severe reactions to insect sting. Larger multicenter studies are needed to further evaluate the rate of SRs to VIT in pediatric patients.

Current Advances in Immunological Studies on the Vespidae Venom Antigen 5: Therapeutic and Prophylaxis to Hypersensitivity Responses

Although systemic reactions caused by allergenic proteins present in venoms affect a small part of the world population, Hymenoptera stings are among the main causes of immediate hypersensitivity responses, with risk of anaphylactic shock. In the attempt to obtain therapeutic treatments and prophylaxis to hypersensitivity responses, interest in the molecular characterization of these allergens has grown in the scientific community due to the promising results obtained in immunological and clinical studies. The present review provides an update on the knowledge regarding the immune response and the therapeutic potential of Antigen 5 derived from Hymenoptera venom. The results confirm that the identification and topology of epitopes, associated with molecular regions that interact with antibodies, are crucial to the improvement of hypersensitivity diagnostic methods.

Characterization of the honeybee venom proteins C1q-like protein and PVF1 and their allergenic potential

Honeybee (Apis mellifera) venom (HBV) represents an ideal model to study the role of particular venom components in allergic reactions in sensitized individuals as well as in the eusociality of Hymenoptera species. The aim of this study was to further characterize the HBV components C1q-like protein (C1q) and PDGF/VEGF-like factor 1 (PVF1). C1q and PVF1 were produced as recombinant proteins in insect cells. Their allergenic properties were examined by determining the level of specific IgE antibodies in the sera of HBV-allergic patients (n = 26) as well as by their capacity to activate patients' basophils (n = 11). Moreover, the transcript heterogeneity of PVF1 was analyzed. It could be demonstrated that at least three PVF1 variants are present in the venom gland, which all result from alternative splicing of one transcript. Additionally, recombinant C1q and PVF1 from Spodoptera frugiperda insect cells exhibited specific IgE reactivity with approximately 38.5% of sera of HBV-allergic patients. Interestingly, both proteins were unable to activate basophils of the patients, questioning their role in the context of clinically relevant sensitization. Recombinant C1q and PVF1 can build the basis for a deeper understanding of the molecular mechanisms of Hymenoptera venoms. Moreover, the conflicting results between IgE sensitization and lack of basophil activation, might in the future contribute to the identification of factors that determine the allergenic potential of proteins.

Component-resolved diagnosis in hymenoptera allergy

Component-resolved diagnosis based on the use of well-defined, properly characterised and purified natural and recombinant allergens constitutes a new approach in the diagnosis of venom allergy. Prospective readers may benefit from an up-to-date review on the allergens. The best characterised venom is that of Apis mellifera, whose main allergens are phospholipase A2 (Api m1), hyaluronidase (Api m2) and melittin (Api m4). Additionally, in recent years, new allergens of Vespula vulgaris have been identified and include phospholipase A1 (Ves v1), hyaluronidase (Ves v2) and antigen 5 (Ves v5). Polistes species are becoming an increasing cause of allergy in Europe, although only few allergens have been identified in this venom. In this review, we evaluate the current knowledge about molecular diagnosis in hymenoptera venom allergy.

Component-resolved diagnostics to direct in venom immunotherapy: Important steps towards precision medicine

Stings of Hymenoptera can induce IgE-mediated systemic and even fatal allergic reactions. Venom-specific immunotherapy (VIT) is the only disease-modifying and curative treatment of venom allergy. However, choosing the correct venom for VIT represents a necessary prerequisite for efficient protection against further anaphylactic sting reactions after VIT. In the past, therapeutic decisions based on the measurement of specific IgE (sIgE) levels to whole venom extracts were not always straightforward, especially when the patient was not able to identify the culprit insect. In the last years, the increasing knowledge about the molecular structure and relevance of important venom allergens and their availability as recombinant allergens, devoid of cross-reactive carbohydrate determinants, resulted in the development of an advanced component-resolved diagnostics (CRD) approach in venom allergy. Already to date, CRD has increased the sensitivity of sIgE detection and enabled the discrimination between primary sensitization and cross-reactivity, particularly in patients with sensitization to both honeybee and vespid venom. Hence, CRD in many patients improves the selection of the appropriate immunotherapeutic intervention. Moreover, the detailed knowledge about sensitization profiles on a molecular level might open new options to identify patients who are at increased risk of side-effects or not to respond to immunotherapy. Therefore, increasing potential of CRD becomes evident, to direct therapeutic decisions in a personalized and patient-tailored manner. Reviewed here are the state of the art options, recent developments and future perspectives of CRD of Hymenoptera venom allergy.

The high molecular weight dipeptidyl peptidase IV Pol d 3 is a major allergen of Polistes dominula venom

Hymenoptera venom allergy can cause severe anaphylaxis in untreated patients. Polistes dominula is an important elicitor of venom allergy in Southern Europe as well as in the United States. Due to its increased spreading to more moderate climate zones, Polistes venom allergy is likely to gain importance also in these areas. So far, only few allergens of Polistes dominula venom were identified as basis for component-resolved diagnostics. Therefore, this study aimed to broaden the available panel of important Polistes venom allergens. The 100 kDa allergen Pol d 3 was identified by mass spectrometry and found to be a dipeptidyl peptidase IV. Recombinantly produced Pol d 3 exhibited sIgE-reactivity with approximately 66% of Polistes venom-sensitized patients. Moreover, its clinical relevance was supported by the potent activation of basophils from allergic patients. Cross-reactivity with the dipeptidyl peptidases IV from honeybee and yellow jacket venom suggests the presence of exclusive as well as conserved IgE epitopes. The obtained data suggest a pivotal role of Pol d 3 as sensitizing component of Polistes venom, thus supporting its status as a major allergen of clinical relevance. Therefore, Pol d 3 might become a key element for proper diagnosis of Polistes venom allergy.

Component Resolved Diagnosis in Hymenoptera Anaphylaxis

PURPOSE OF REVIEW

Hymenoptera anaphylaxis is one of the leading causes of severe allergic reactions and can be fatal. Venom-specific immunotherapy (VIT) can prevent a life-threatening reaction; however, confirmation of an allergy to a Hymenoptera venom is a prerequisite before starting such a treatment. Component resolved diagnostics (CRD) have helped to better identify the responsible allergen.

RECENT FINDINGS

Many new insect venom allergens have been identified within the last few years. Commercially available recombinant allergens offer new diagnostic tools for detecting sensitivity to insect venoms. Additional added sensitivity to nearly 95% was introduced by spiking yellow jacket venom (YJV) extract with Ves v 5. The further value of CRD for sensitivity in YJV and honey bee venom (HBV) allergy is more controversially discussed. Recombinant allergens devoid of cross-reactive carbohydrate determinants often help to identify the culprit venom in patients with double sensitivity to YJV and HBV. CRD identified a group of patients with predominant Api m 10 sensitization, which may be less well protected by VIT, as some treatment extracts are lacking this allergen. The diagnostic gap of previously undetected Hymenoptera allergy has been decreased via production of recombinant allergens. Knowledge of analogies in interspecies proteins and cross-reactive carbohydrate determinants is necessary to distinguish relevant from irrelevant sensitizations.

Allergen-specific immunotherapy of Hymenoptera venom allergy - also a matter of diagnosis

Stings of hymenoptera can induce IgE-mediated hypersensitivity reactions in venom-allergic patients, ranging from local up to severe systemic reactions and even fatal anaphylaxis. Allergic patients' quality of life can be mainly improved by altering their immune response to tolerate the venoms by injecting increasing venom doses over years. This venom-specific immunotherapy is highly effective and well tolerated. However, component-resolved information about the venoms has increased in the last years. This knowledge is not only able to improve diagnostics as basis for an accurate therapy, but was additionally used to create tools which enable the analysis of therapeutic venom extracts on a molecular level. Therefore, during the last decade the detailed knowledge of the allergen composition of hymenoptera venoms has substantially improved diagnosis and therapy of venom allergy. This review focuses on state of the art diagnostic and therapeutic options as well as on novel directions trying to improve therapy.

Debates in Allergy Medicine: Allergy skin testing cannot be replaced by molecular diagnosis in the near future

Percutaneous skin prick tests (SPT) have been considered the preferred method for confirming IgE-mediated sensitization. This reliable and minimally invasive technique correlates with in vivo challenges, has good reproducibility, is easily quantified, and allows analyzing multiple allergens simultaneously. Potent extracts and a proficient tester improve its accuracy.

Molecular-based allergy diagnostics (MA-Dx) quantifies allergenic components obtained either from purification of natural sources or recombinant technology to identify the patient’s reactivity to those specific allergenic protein components. For a correct allergy diagnosis, the patient selection is crucial. MA-Dx has been shown to have a high specificity, however, as MA-Dx testing can be ordered by any physician, the pre-selection of patients might not always be optimal, reducing test specificity. Also, MA-Dx is less sensitive than in vitro testing with the whole allergen or SPT. Secondly, no allergen-specific immunotherapy (AIT) trial has yet shown efficacy with patients selected on the basis of their MA-Dx results. Thirdly, why would we need molecular diagnosis, as no molecular treatment can yet be offered? Then there are the practical arguments of costs (SPT highly cost-efficient), test availability for MA-Dx still lacking in wide areas of the world and scarce in others. As such, it is hard physicians can build confidence in the test and their interpretation of the MA-Dx results. In conclusion: as of now these techniques should be reserved for situations of complex allergies and polysensitization; in the future MA-Dx might help to reduce the number of allergens for AIT, but trials are needed to prove this concept.

Heterologous Expression, Purification and Immunoreactivity of the Antigen 5 from Polybia paulista Wasp Venom

Polybia paulista (Hymenoptera: Vespidae) is responsible for a high number of sting accidents and anaphylaxis events in Southeast Brazil, Argentina and Paraguay. The specific detection of allergy to the venom of this wasp is often hampered by the lack of recombinant allergens currently available for molecular diagnosis. Antigen 5 (~23 kDa) from P. paulista venom (Poly p 5) is a highly abundant and glycosylated allergenic protein that could be used for development of component-resolved diagnosis (CRD). Here, we describe the cloning and heterologous expression of the antigen 5 (rPoly p 5) from P. paulista venom using the eukaryotic system Pichia pastoris. The expression as a secreted protein yielded high levels of soluble rPoly p 5. The recombinant allergen was further purified to homogeneity (99%) using a two-step chromatographic procedure. Simultaneously, the native form of the allergen (nPoly p 5) was purified from the wasp venom by Ion exchange chromatography. The rPoly p 5 and nPoly p 5 were then submitted to a comparative analysis of IgE-mediated immunodetection using sera from patients previously diagnosed with sensitization to wasp venoms. Both rPoly p 5 and nPoly p 5 were recognized by specific IgE (sIgE) in the sera of the allergic individuals. The high levels of identity found between nPoly p 5 and rPoly p 5 by the alignment of its primary sequences as well as by 3-D models support the results obtained in the immunoblot. Overall, we showed that P. pastoris is a suitable system for production of soluble rPoly p 5 and that the recombinant allergen represents a potential candidate for molecular diagnosis of P.paulista venom allergy.

Molecular diagnosis and immunotherapy

PURPOSE OF REVIEW

To describe recent insights into how molecular diagnosis can improve indication and selection of suitable allergens for specific immunotherapy and increase the safety of this therapy.

RECENT FINDINGS

As specific allergen immunotherapy targets specific allergens, identification of the disease-eliciting allergen is a prerequisite for accurate prescription of treatment. In areas of complex sensitization to aeroallergens or in cases of hymenoptera venom allergy, the use of molecular diagnosis has demonstrated that it may lead to a change in indication and selection of allergens for immunotherapy in a large proportion of patients when compared with diagnosis based on skin prick testing and/or specific IgE determination with commercial extracts. These changes in immunotherapy prescription aided by molecular diagnosis have been demonstrated to be cost-effective in some scenarios. Certain patterns of sensitization to grass or olive pollen and bee allergens may identify patients with higher risk of adverse reaction during immunotherapy.

SUMMARY

Molecular diagnosis, when used with other tools and patients' clinical records, can help clinicians better to select the most appropriate patients and allergens for specific immunotherapy and, in some cases, predict the risk of adverse reactions. The pattern of sensitization to allergens could potentially predict the efficacy of allergen immunotherapy provided that these immunotherapy products contain a sufficient amount of these allergens. Nevertheless, multiplex assay remains a third-level approach, not to be used as screening method in current practice.