IgE and allergen-specific immunotherapy-induced IgG4 recognize similar epitopes of Bet v 1, the major allergen of birch pollen

Peptide epitopes as biomarkers of soya sensitization in rBet v 1 immunotherapy of birch-related soya allergy

BACKGROUND

There are no diagnostic and/or prognostic markers of the treatment outcome in patients receiving allergen immunotherapy (AIT). Although numerous allergen epitopes are known, their value in this context has not been investigated. This paper deals with re-evaluation of sera from patients who underwent AIT against rBet v 1 for treatment of their soya allergy (BASALIT trial).

OBJECTIVE

To evaluate the diagnostic and/or prognostic potential of allergen epitopes recognition by antibodies from patients with birch-related soya allergy before and after rBet v 1-immunotherapy.

METHODS

PR-10 epitope-binding profiles from 34 patients were identified in silico using a statistical peptide phage display at start and at end of AIT. IgE- and IgG-binding to these peptide epitopes was measured in peptide microarrays. Clinical relevance of epitopes was evaluated by comparing these measurements to a number of treatment outcome measures recorded during double-blind placebo-controlled food challenge at start and end of AIT.

RESULTS

We showed that IgG- and IgE-recognition of peptide epitopes after AIT were surrogate markers of 5 out of 12 analysed treatment outcome measures using this patient cohort. Seven epitopes were identified from multiple PR-10 allergen sequences. Twenty-six peptide epitopes were used for IgG and IgE measurements. IgE-binding to one of the epitopes was associated with stronger intensity of oral tingling/itching after ingesting soya at start of AIT. IgG recognizing two other epitopes at start of AIT could predict decreased Cor a 1-specific IgE concentration (p = .043) and decreased lip swelling intensity (p = .016) after AIT. Tolerance to increasing amounts of soy at food challenge correlated with IgG-binding to another epitope at start of AIT (p = .046).

CONCLUSION

IgG- and IgE-binding to peptide epitopes in PR-10 is a potential indicator of the outcome and clinical course of AIT of soya-sensitized patients with rBet v 1.

IgE Epitope Analysis for Scy p 1 and Scy p 3, the Heat-Stable Myofibrillar Allergens in Mud Crab

Tropomyosin (Scy p 1) and myosin light chain (Scy p 3) are investigated to be important heat-stable allergens in Scylla paramamosain. However, the epitopes of Scy p 1 and Scy p 3 are limited. In this study, recombinant Scy p 1 and Scy p 3 had similar IgE-binding capacity to natural proteins. Mimotopes of Scy p 1 and Scy p 3 were analyzed by bioinformatics, phage display, and one-bead-one-compound technology. Ten linear epitopes of Scy p 1 and seven linear epitopes of Scy p 3 were identified by synthetic peptides and inhibition dot blot. Meanwhile, three conformational epitopes of Scy p 1 and seven conformational epitopes of Scy p 3 were verified by site-directed mutagenesis and the serological test. Furthermore, strong IgE-binding epitopes of Scy p 1 and Scy p 3 were conserved in multiple crustaceans. Overall, these epitopes could enhance our understanding of crab allergens, which lay the foundation for a cross-reaction.

Circulating C-X-C Motif Ligand 13 as a Biomarker for Early Predicting Efficacy of Subcutaneous Immunotherapy in Children With Chronic Allergic Rhinitis

BACKGROUND

C-X-C motif ligand 13 (CXCL13) and B cell-activating factor (BAFF) are proven to be involved in inflammatory diseases, but their role in allergic rhinitis (AR) remains unclear. The aim of this study was to investigate the role of serum CXCL13 and BAFF in AR and their clinical values as objective biomarkers to predict the efficacy of subcutaneous immunotherapy (SCIT).

METHODS

We prospectively recruited 90 children with AR treated with SCIT and collected their serum specimens before SCIT. One-year follow-up was conducted for all patients, and they were categorized into effective and ineffective groups based on efficacy. The serum concentrations of CXCL13 and BAFF were detected and compared between the two groups. A validation cohort of 52 responders and 26 non-responders were further assessed for both cytokines and serum CXCL13 and BAFF levels were assayed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Eighty children completed the follow-up schedule, and 56 children were categorized into the effective group and 24 children into the ineffective group. The serum levels of CXCL13 in the effective group were clearly higher than those in the ineffective group (P < 0.05). Receiver operating characteristic (ROC) curves revealed the potential values of CXCL13 as a biomarker in predicting the response of SCIT. Further, in the validation cohort, ELISA results demonstrated that serum CXCL13 levels were increased in responders than non-responders (P < 0.05). ROC curves showed good accuracy of serum CXCL13 in predicting the efficacy of SCIT.

CONCLUSION

Our discovery-validation study demonstrated that circulating CXCL13 might serve as a novel biomarker to predict the outcome of SCIT in childhood AR. The findings indicated that CXCL13 was involved in the pathological mechanisms of AR and made help to the fundamental therapeutic mechanism of SCIT.

Efficacy and Safety of Subcutaneous Immunotherapy for Local Allergic Rhinitis: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Subcutaneous immunotherapy (SCIT) has been used for treating local allergic rhinitis (LAR) patients. However, the clinical efficacy and safety were still questioned.

OBJECTIVE

This study was designed to estimate the efficacy and safety of SCIT for treating LAR patients through meta-analysis.

METHODS

We systemically searched MEDLINE, Cochrane Library, and Embase publications. Randomized, double-blind, clinical trials for the efficacy and safety of Allergen Immunotherapy (AIT) for LAR were included. A meta-analysis of 4 clinical endpoints (combined symptom and medication scores [CSMS], symptom scores [SS], medication scores [MS] and rhinoconjunctivitis quality of life questionnaire [RQLQ]) and adverse events (AEs)) was performed after bias and heterogeneity assessments. The immunologic response results were summarized.

RESULTS

Four RCTs with 134 patients were included. Four studies for analyzing primary outcomes (CSMS, SS, MS) and AEs, three for RQLQ results. The results indicated an important significant difference between SCIT and placebo groups, list as follows: CSMS (SMD = -2.42, 95% CI: -3.60 to -1.25, P < .0001), SS (SMD = -2.08, 95% CI -3.68 to -0.48, P = .01), MS (SMD = -1.43, 95% CI: -2.65 to -0.21, P = 0.02), RQLQ (SMD = -0.70, 95% CI -1.29 to -0.12, P = .02), Local AEs (RR = 4.13, 95% CI 1.08 to 15.77, P = .04). For immunologic response, significantly increased serum sIgG4 levels and improvements of allergen tolerance was observed after SCIT.

CONCLUSIONS

Our meta-analysis suggests that SCIT has a significant effect on improving symptoms and reducing medicine consumption for LAR patients. Larger and multicenter clinical trials are needed to clarify the safety and long-term efficacy.

Recombinant Bet v 1-BanLec chimera modulates functional characteristics of peritoneal murine macrophages by promoting IL-10 secretion

Allergen-specific immunotherapy (AIT) is a desensitizing treatment for allergic diseases that corrects the underlined pathological immune response to innocuous protein antigens, called allergens. Recombinant allergens employed in the AIT allowed the production of well-defined formulations that possessed consistent quality but were often less efficient than natural allergen extracts. Combining recombinant allergens with an adjuvant or immunomodulatory agent could improve AIT efficacy. This study aimed to perform structural and functional characterization of newly designed recombinant chimera composed of the Bet v 1, the major birch pollen allergen, and Banana Lectin (BanLec), TLR2, and CD14 binding protein, for the application in AIT. rBet v 1-BanLec chimera was designed in silico and expressed as a soluble fraction in Escherichia coli. Purified rBet v 1-BanLec (33.4 kDa) retained BanLec-associated biological activity of carbohydrate-binding and preserved IgE reactive epitopes of Bet v 1. The chimera revealed secondary structures with predominant β sheets. The immunomodulatory capacity of rBet v 1-BanLec tested on macrophages showed changes in myeloperoxidase activity, reduced NO production, and significant alterations in the production of cytokines when compared to both rBanLec and rBet v 1. Comparing to rBet v 1, rBet v 1-BanLec was demonstrated to be more efficient promoter of IL-10 production as well as weaker inducer of NO production and secretion of pro-inflammatory cytokines TNFα, and IL-6. The ability of rBet v 1-BanLec to promote IL-10 in together with the preserved 3D structure of Bet v 1 part implies that the construct might exert a beneficial effect in the allergen-specific immunotherapy.

Mechanisms of Allergen Immunotherapy in Allergic Rhinitis

PURPOSE OF REVIEW

Allergic rhinitis (AR) is a chronic inflammatory immunoglobulin (Ig) E-mediated disease of the nasal mucosa that can be triggered by the inhalation of seasonal or perennial allergens. Typical symptoms include sneezing, rhinorrhea, nasal itching, nasal congestion and symptoms of allergic conjunctivitis. AR affects a quarter of the population in the United States of America and Europe.

RECENT FINDINGS

AR has been shown to reduce work productivity in 36-59% of the patients with 20% reporting deteriorated job attendance. Moreover, 42% of children with AR report reduced at-school productivity and lower grades. Most importantly, AR impacts the patient's quality of life, due to sleep deprivation. However, a proportion of patients fails to respond to conventional medication and opts for the allergen immunotherapy (AIT), which currently is the only disease-modifying therapeutic option. AIT can be administered by either subcutaneous (SCIT) or sublingual (SLIT) route. Both routes of administration are safe, effective, and can lead to tolerance lasting years after treatment cessation. Both innate and adaptive immune responses that contribute to allergic inflammation are suppressed by AIT. Innate responses are ameliorated by reducing local mast cell, basophil, eosinophil, and circulating group 2 innate lymphoid cell frequencies which is accompanied by decreased basophil sensitivity. Induction of allergen-specific blocking antibodies, immunosuppressive cytokines, and regulatory T and B cell phenotypes are key pro-tolerogenic adaptive immune responses.

CONCLUSION

A comprehensive understanding of these mechanisms is necessary for optimal selection of AIT-responsive patients and monitoring treatment efficacy. Moreover, it could inspire novel and more efficient AIT approaches.

High-Yield Production of the Major Birch Pollen Allergen Bet v 1 With Allergen Immunogenicity in Nicotiana benthamiana

Type I allergy is an immunological disorder triggered by allergens and causes significant health problems. The major allergen of birch pollen is Bet v 1, which belongs to the pathogen-related protein 10 (PR-10) family. Here, we established a rapid and robust method for the production of Bet v 1 in Nicotiana benthamiana leaves, with binding activity to allergic patients' IgE. The Bet v 1 allergen was expressed in N. benthamiana using a strong agroinfiltration-based transient protein expression system, which consists of a deconstructed geminiviral vector system with a double terminator. Five days post-infiltration, the allergen concentration in N. benthamiana leaves was 1.2 mg/g of fresh mass, being this the maximum yield of Bet v 1 in plants reported up to now. A part of plant-derived Bet v 1 was glycosylated. Bet v 1 purified from N. benthamiana or Brevibacillus brevis was used to carry out enzyme-linked immunoassays; both recombinant allergens were found to have comparable binding properties to the IgE of allergic patients. These results suggest that our plant expression system allows rapid and robust production of the allergen, which keeps the immunogenicity.

Developments in the field of allergy in 2017 through the eyes of Clinical and Experimental Allergy

In this article, we described the development in the field of allergy as described by Clinical and Experimental Allergy in 2017. Experimental models of allergic disease, basic mechanisms, clinical mechanisms, allergens, asthma and rhinitis and clinical allergy are all covered.

Does clinical outcome of birch pollen immunotherapy relate to induction of blocking antibodies preventing IgE from allergen binding? A pilot study monitoring responses during first year of AIT

Background

The clinical benefit of allergen-specific immunotherapy (AIT) involves induction of blocking antibodies. It is not clear if these antibodies function via steric hindrance alone or a combination of levels, avidities, and epitope specificities, and clinical outcome cannot be predicted. We aim to in-depth characterize serum antibody profiles during birch pollen AIT, investigate therapy-induced antibodies for their capacity to block IgE binding to Bet v 1 and correlate data with clinical outcomes.

Methods

Immune responses of five birch pollen allergic patients were monitored during the first year of AIT by nasal provocation tests (NPTs), ImmunoCAP, immunoblots, direct and avidity enzyme-linked immunosorbent assays, mediator release assays, facilitated antigen binding (FAB) assays, and inhibition mediator release assays.

Results

There was no correlation between NPT results and therapy-induced changes in levels (IgE, IgG, IgA, IgM), avidities, or mediator release potency of Bet v 1-specific antibodies. In FAB assays, blocking antibodies initiated upon AIT were shown to prevent formation of Bet v 1-IgE complexes of an indicator serum pool and significantly correlated with clinical readout. Inhibition mediator release assays using patient-specific IgE for passive sensitization revealed therapy-induced blocking capacities with very good correlation to NPT results. Notably, this assay was the only one to detect a non-responder during treatment in this pilot study.

Conclusions

Clinical outcome of AIT depends on induction of blocking antibodies able to prevent the patient’s own IgE from allergen binding. Monitoring of clinical efficacy seems to be best achieved using the inhibition mediator release assay, as development of relevant blocking antibodies can be verified in a patient-tailored manner.

Electronic supplementary material

The online version of this article (10.1186/s13601-018-0226-7) contains supplementary material, which is available to authorized users.

Evolution of the IgE and IgG repertoire to a comprehensive array of allergen molecules in the first decade of life

BACKGROUND

In early childhood, the allergen-specific IgG repertoire is mainly directed to animal and vegetable food molecules and infrequently to airborne molecules. It is unknown whether this early pattern is maintained throughout childhood.

OBJECTIVE

To investigate the evolution of IgG and IgE responses to a broad panel of allergenic molecules from birth to age 10 years.

METHODS

We examined the sera collected between birth and age 10 years from participants in the German Multicentre Allergy Study, a birth cohort born in 1990. The IgE (cutoff ≥0.30 ISU) and IgG (cutoff ≥0.10 ISU) responses to 35 genuine allergenic molecules were measured with a multiplex microarray approach (ImmunoCAP ISAC™).

RESULTS

IgE responses were mostly directed against a restricted group of airborne molecules, with a sequence and prevalence hierarchy (Phl p 1> Bet v 1> Fel d 1> Phl p 5> Der p 2> Der p 1) largely maintained over time. Conversely, the IgG repertoire was much broader, starting with animal foodborne, then spreading to vegetable foodborne and finally to airborne molecules. A strong and persistent IgG response to a given airborne molecule almost invariably preceded or accompanied an IgE response to that molecule.

CONCLUSIONS

The evolution of IgG and IgE responses throughout childhood differs widely at population level. IgG responses are mostly directed to animal food allergens, while IgE responses are dominated by airborne allergens. However, a strong IgG response almost invariably precedes or accompanies the appearance of IgE to the same molecule in specifically sensitized subjects.