The future of antigen-specific immunotherapy of allergy

Can Physicochemical Properties Alter the Potency of Aeroallergens? Part 2 - Impact of Physicochemical Properties

PURPOSE OF REVIEW

A holistic perspective on how physicochemical properties modulate the allergenicity of proteins has recently been performed for food allergens, launching the challenge of a similar analysis for aeroallergens. After a first review on aeroallergen classification into protein families (Part 1), this second part (Part 2) will exploit the impact of physicochemical properties (abundance/biological function, protein structure/presence of post-translational modifications, ligand/cofactor/lipid-binding) on inhalant protein allergenicity.

RECENT FINDINGS

The abundance linked to biological function is correlated with increased allergenic risk for most protein families, while the loss of structural integrity with consequent destruction of conformational epitopes is well linked with decreased allergenicity. Ligand-binding effect totally depends on the ligand type being highly variable among aeroallergens. Knowledge about the physicochemical properties of aeroallergens is still scarce, which highlights the need for research using integrated approaches (in silico and experimental) to generate and analyze new data on known/new aeroallergens.

IgE to cyclophilins in pollen-allergic children: Epidemiologic, clinical, and diagnostic relevance of a neglected panallergen

BACKGROUND

Cyclophilins are ubiquitous panallergens whose epidemiologic, diagnostic, and clinical relevance is largely unknown and whose sensitization is rarely examined in routine allergy practice.

OBJECTIVE

We investigated the epidemiologic, diagnostic, and clinical relevance of cyclophilins in seasonal allergic rhinitis and its comorbidities.

METHODS

We examined a random sample of 253 (25%) of 1263 Italian children with seasonal allergic rhinitis from the Panallergens in Pediatrics (PAN-PED) cohort with characterized disease phenotypes. Nested studies of sensitization prevalence, correlation, and allergen extract inhibition were performed in patients sensitized to birch pollen extract but lacking IgE to Bet v 1/2/4 (74/1263) or with highest serum level of IgE to Bet v 1 (26/1263); and in patients with sensitization to various extracts (ragweed, mugwort, pellitory, Plantago, and plane tree), but not to their respective major allergenic molecule, profilins, and polcalcins. IgE to cyclophilin was detected with recombinant Bet v 7, and extract inhibition tests were performed with the same rBet v 7.

RESULTS

IgE to rBet v 7 was detected in 43 (17%) of 253 patients. It was associated with asthma (P < .028) and oral allergy syndrome (P < .017) in univariate but not multivariate analysis adjusted for IgE to profilins (Phl p 12), PR-10s (Bet v 1), and lipid transfer proteins (Pru p 3). IgE to rBet v 7 was also highly prevalent (47/74, 63%) among patients with unexplained sensitization to birch pollen extract. In patients with unexplained sensitization to ragweed, mugwort, pellitory, Plantago and plane tree pollen, the levels of IgE to those extracts correlated with the levels of IgE to rBet v 7, and they were also significantly inhibited by rBet v 7 (inhibition range 45%-74%).

CONCLUSIONS

IgE sensitization to cyclophilin is frequent in pollen-allergic patients living in temperate areas and can produce "false" positive outcomes in skin prick and IgE tests to pollen extracts. Molecular diagnostic guidelines should include this panallergen family.

Preventive allergen immunotherapy with inhalant allergens in children

The efficacy and safety of preventive allergen immunotherapy (pAIT) in children are currently under investigation. Here, we provide an overview of pAIT with respiratory allergens concerning the prevention of new sensitizations, allergic disease onset and progression as well as further immunomodulatory effects. Three databases were searched for clinical pAIT studies in children. Selected publications were reviewed for preventive outcomes according to prevention level (primary, secondary, and tertiary), allergen type, administration route, dose, and treatment duration. The primary prevention approach appears safe but showed no allergen-specific effect on new sensitizations. Secondary prevention seems feasible and may induce regulatory T cell-mediated immunotolerance. The number of studies at these prevention levels is limited. Tertiary prevention with grass and/or tree pollen-based pAIT has shown efficacy in preventing disease progression from allergic rhinitis/conjunctivitis to asthma. Data on tertiary pAIT with house dust mites and other allergen types are inconclusive. Subcutaneous and sublingual routes appear similarly effective, but head-to-head comparative paediatric studies are scarce. Additionally, there are fewer placebo-controlled studies. Nevertheless, immunomodulatory outcomes of pAIT are encouraging. Currently, limited but favourably suggestive evidence is available for preventing respiratory allergic diseases in children by pAIT. Primary and secondary prevention have potential and warrant further investigation through well-designed studies.

Design of an Ara h 2 hypoallergen from conformational epitopes

INTRODUCTION

Adverse reactions are relatively common during peanut oral immunotherapy. To reduce the risk to the patient, some researchers have proposed modifying the allergen to reduce IgE reactivity, creating a putative hypoallergen. Analysis of recently cloned human IgG from patients treated with peanut immunotherapy suggested that there are three common conformational epitopes for the major peanut allergen Ara h 2. We sought to test if structural information on these epitopes could indicate mutagenesis targets for designing a hypoallergen and evaluated the reduction in IgE binding via immunochemistry and a mouse model of passive cutaneous anaphylaxis (PCA).

METHODS

X-ray crystallography characterized the conformational epitopes in detail, followed by mutational analysis of key residues to modify monoclonal antibody (mAb) and serum IgE binding, assessed by ELISA and biolayer interferometry. A designed Ara h 2 hypoallergen was tested for reduced vascularization in mouse PCA experiments using pooled peanut allergic patient serum.

RESULTS

A ternary crystal structure of Ara h 2 in complex with patient antibodies 13T1 and 13T5 was determined. Site-specific mutants were designed that reduced 13T1, 13T5, and 22S1 mAbs binding by orders of magnitude. By combining designed mutations from the three major conformational bins, a hexamutant (Ara h 2 E46R, E89R, E97R, E114R, Q146A, R147E) was created that reduced IgE binding in serum from allergic patients. Further, in the PCA model where mice were primed with peanut allergic patient serum, reactivity upon allergen challenge was significantly decreased using the hexamutant.

CONCLUSION

These studies demonstrate that prior knowledge of common conformational epitopes can be used to engineer reduced IgE reactivity, an important first step in hypoallergen design.

Stimulation of naïve B cells with a fusion protein consisting of FlaA and Bet v 1 induces regulatory B cells ex vivo

BACKGROUND

The experimental fusion protein rFlaA:Betv1 was shown to efficiently suppress allergen-specific sensitization in mice. However, the detailed mechanism of rFlaA:Betv1-mediated immune modulation is not fully understood. In this study, we investigated the effect of rFlaA:Betv1 on naïve murine B cells.

METHODS

Immune modulating capacity of rFlaA:Betv1 was screened in IL-10 reporter mice. B cells were isolated from spleens of naïve C57Bl/6, TLR5^-/- , or MyD88^-/- mice, stimulated with rFlaA:Betv1 and controls, and monitored for the expression of the regulatory B cell markers CD1d, CD24, CD38, and surface IgM by flow cytometry. Secreted cytokines, antibodies, and reactivity of the induced antibodies were investigated by ELISA and intracellular flow cytometry. Suppressive capacity of rFlaA:Betv1-stimulated B cells was tested in mDC:CD4⁺ T cell:B cell triple cultures.

RESULTS

Upon in vivo application of rFlaA:Betv1 into IL-10-GFP reporter mice, CD19⁺ B cells were shown to produce anti-inflammatory IL-10, suggesting B cells to contribute to the immune-modulatory properties of rFlaA:Betv1. rFlaA:Betv1-induced IL-10 secretion was confirmed in human B cells isolated from buffy coats. In vitro stimulation of naïve murine B cells with rFlaA:Betv1 resulted in an mTOR- and MyD88-dependent production of IL-10 and rFlaA:Betv1 induced Bet v 1-reactive IgG production, which was not observed for IgA. rFlaA:Betv1-stimulated B cells formed a CD19⁺ CD24⁺ CD1d⁺ IgM⁺ CD38⁺ Breg subpopulation capable of suppressing Bet v 1-induced TH2 cytokine secretion in vitro.

CONCLUSION

rFlaA:Betv1 can act as a thymus-independent B cell antigen, stimulating the mTOR- and MyD88-dependent differentiation of B cells displaying a regulatory phenotype, IL-10 secretion, antigen-binding antibody production, and a suppressive capacity in vitro.

Wearable chemical sensors for biomarker discovery in the omics era

Biomarkers are crucial biological indicators in medical diagnostics and therapy. However, the process of biomarker discovery and validation is hindered by a lack of standardized protocols for analytical studies, storage and sample collection. Wearable chemical sensors provide a real-time, non-invasive alternative to typical laboratory blood analysis, and are an effective tool for exploring novel biomarkers in alternative body fluids, such as sweat, saliva, tears and interstitial fluid. These devices may enable remote at-home personalized health monitoring and substantially reduce the healthcare costs. This Review introduces criteria, strategies and technologies involved in biomarker discovery using wearable chemical sensors. Electrochemical and optical detection techniques are discussed, along with the materials and system-level considerations for wearable chemical sensors. Lastly, this Review describes how the large sets of temporal data collected by wearable sensors, coupled with modern data analysis approaches, would open the door for discovering new biomarkers towards precision medicine.

New insights on the role of human leukocyte antigen complex in primary biliary cholangitis

Primary Biliary Cholangitis (PBC) is a rare autoimmune cholangiopathy. Genetic studies have shown that the strongest statistical association with PBC has been mapped in the human leukocyte antigen (HLA) locus, a highly polymorphic area that mostly contribute to the genetic variance of the disease. Furthermore, PBC presents high variability throughout different population groups, which may explain the different geoepidemiology of the disease. A major role in defining HLA genetic contribution has been given by genome-wide association studies (GWAS) studies; more recently, new technologies have been developed to allow a deeper understanding. The study of the altered peptides transcribed by genetic alterations also allowed the development of novel therapeutic strategies in the context of immunotolerance. This review summarizes what is known about the immunogenetics of PBC with a focus on the HLA locus, the different distribution of HLA alleles worldwide, and how HLA modifications are associated with the pathogenesis of PBC. Novel therapeutic strategies are also outlined.

Effects of rAmb a 1-Loaded PLGA-PEG Nanoparticles in a Murine Model of Allergic Conjunctivitis

Ambrosia artemisiifolia (Amb a) contains many allergens. Allergic conjunctivitis caused by Ambrosia artemisiifolia and its related allergen-specific immunotherapy (AIT) are seldom studied at present. poly(DL-lactide-co-glycolide)-polyethylene glycol (PLGA-PEG) is a very good nano-carrier, which has been applied in the medical field. In this context, we studied the immunotherapy effect and potential mechanism of recombinant Amb a 1 (rAmb a 1)-loaded PLGA-PEG nanoparticles. A mouse allergic conjunctivitis model was established with Ambrosia artemisiifolia crude extract, and the nanoparticles were used for AIT through direct observation of conjunctival tissue, degranulation of mast cells in conjunctival tissue, serum-specific antibodies, cytokines and other assessment models. The treatment of nanoparticles enhanced the secretion of T-helper 1 (Th1) cytokine Interferon-gama (IFN-γ) and the production of immunoglobulin G (IgG)2a (IgG2a), inhibited the secretion of T-helper 2 (Th2) cytokine Interleukin (IL)-13 and IL-4 and the level of IgE. Especially, degranulation of mast cells and expression of mast cell protease-1 (MCP-1) in conjunctival tissue was reduced significantly. In this study, we proved that the nanoparticles prepared by rAmb a 1 and PLGA-PEG have an immunotherapy effect on allergic conjunctivitis in mice.

Neutralization of SARS-CoV-2 requires antibodies against conformational receptor-binding domain epitopes

Background

The determinants of successful humoral immune response to the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) are of critical importance for the design of effective vaccines and the evaluation of the degree of protective immunity conferred by exposure to the virus. As novel variants emerge, understanding their likelihood of suppression by population antibody repertoires has become increasingly important.

Methods

In this study, we analyzed the SARS‐CoV‐2 polyclonal antibody response in a large population of clinically well‐characterized patients after mild and severe COVID‐19 using a panel of microarrayed structurally folded and unfolded SARS‐CoV‐2 proteins, as well as sequential peptides, spanning the surface spike protein (S) and the receptor‐binding domain (RBD) of the virus.

Results

S‐ and RBD‐specific antibody responses were dominated by immunoglobulin G (IgG), mainly IgG₁, and directed against structurally folded S and RBD and three distinct peptide epitopes in S2. The virus neutralization activity of patients´ sera was highly correlated with IgG antibodies specific for conformational but not sequential RBD epitopes and their ability to prevent RBD binding to its human receptor angiotensin‐converting enzyme 2 (ACE2). Twenty percent of patients selectively lacked RBD‐specific IgG. Only immunization with folded, but not with unfolded RBD, induced antibodies against conformational epitopes with high virus‐neutralizing activity. Conformational RBD epitopes required for protection do not seem to be altered in the currently emerging virus variants.

Conclusion

These results are fundamental for estimating the protective activity of antibody responses after natural infection or vaccination and for the design of vaccines, which can induce high levels of SARS‐CoV‐2–neutralizing antibodies conferring sterilizing immunity.

Increase in Indoor Inhalant Allergen Sensitivity During the COVID-19 Pandemic in South China: A Cross-Sectional Study from 2017 to 2020

Purpose

Public health measures during COVID-19 have led to an unprecedented change in social lifestyle which might have an impact on the allergen sensitization in population. We sought to explore the prevalence patterns of serum inhalant and food allergen-specific IgE (sIgE) sensitization and serum total immunoglobulin E (tIgE) level among patients with clinical symptoms of suspected allergic diseases before and during the COVID-19 pandemic in south China.

Patients and Methods

A large epidemiology study was conducted on the prevalence patterns of sIgE sensitization and serum tIgE level among 13,715 patients with allergic symptoms in south China from 2017 to 2020. Chi-square test and Fisher exact test were used to test statistical significance of allergen sensitization difference among years. Logistic regression was performed to assess the magnitudes of the differences among years by adjusted odds ratios and 95% confidence intervals.

Results

The number of hospital visits for patients with suspected allergy symptoms decreased during COVID-19. The positive rates of indoor inhalant allergens (house dust mites, German cockroach, dog dander) and tIgE increased significantly in 2020, while no significant differences were found in food allergens (egg white, milk, soya bean, shrimp) before and during the COVID-19 pandemic. The odds of sIgE positives in indoor inhalant allergens and tIgE positive for 2017 and 2020 were all larger than 1.00. After grouping by age and gender, there were significant differences in the positive rates of indoor inhalant allergens and tIgE when comparing 2020 with 2017.

Conclusion

The prevalence of sensitization increased significantly to indoor inhalant allergens but not to food allergens in south China during the COVID-19 pandemic.

DNA vaccines and recombinant allergens with reduced allergenic activity treat allergies

This review is intended to familiarize readers with major novel directions of developing allergy vaccines, their structure, as well as the mechanisms of forming a new immunological response in the course of the treating immunoglobulin E (IgE)-mediated allergic diseases. Currently, science offers a huge variety of new experimental forms of recombinant allergens with reduced allergenic activity and increased immunogenicity, or vice-versa, immune tolerance. Often, the mechanisms of their effect on the immune system are not fully understood. Scientific publications, including reviews covering this topic, allowed us identifying top priority areas in the development of allergy vaccines: recombinant hypoallergenic allergen derivatives, T cell epitope-based allergy vaccines, and B cell epitope-based allergy vaccines. In addition, the review discusses use of deoxyribonucleic acid (DNA) vaccines. Immunotherapy with DNA vaccines is the newest and least studied method of treating allergic diseases.

pH-Induced Local Unfolding of the Phl p 6 Pollen Allergen From cpH-MD

Susceptibility to endosomal degradation is a decisive contribution to a protein's immunogenicity. It is assumed that the processing kinetics of structured proteins are inherently linked to their probability of local unfolding. In this study, we quantify the impact of endosomal acidification on the conformational stability of the major timothy grass pollen allergen Phl p 6. We use state of the art sampling approaches in combination with constant pH MD techniques to profile pH-dependent local unfolding events in atomistic detail. Integrating our findings into the current view on type 1 allergic sensitization, we characterize local protein dynamics in the context of proteolytic degradation at neutral and acidic pH for the wild type protein and point mutants with varying proteolytic stability. We analyze extensive simulation data using Markov state models and retrieve highly reliable thermodynamic and kinetic information at varying pH levels. Thereby we capture the impact of endolysosomal acidification on the structure and dynamics of the Phl p 6 mutants. We find that upon protonation at lower pH values, the conformational flexibilities in key areas of the wild type protein, i.e., T-cell epitopes and early proteolytic cleavage sites, increase significantly. A decrease of the pH even leads to local unfolding in otherwise stable secondary structure elements, which is a prerequisite for proteolytic cleavage. This effect is even more pronounced in the destabilized mutant, while no unfolding was observed for the stabilized mutant. In summary, we report detailed structural models which rationalize the experimentally observed cleavage pattern during endosomal acidification.

Bet v 1 contiguous overlapping peptides anchored to virosomes with TLR4 agonist enhance immunotherapy efficacy in mice

BACKGROUND

Whereas sublingual allergen immunotherapy (AIT) is routinely performed without any adjuvant or delivery system, there is a strong scientific rationale to better target the allergen(s) to oral dendritic cells known to support regulatory immune responses by using appropriate presentation platforms.

OBJECTIVE

To identify a safe presentation platform able to enhance allergen-specific tolerance induction.

METHODS

Virosomes with membrane-integrated contiguous overlapping peptides (COPs) of Bet v 1 and TLR4 or TLR2/TLR7 agonists were assessed for induction of Bet v 1-specific IgG1, IgG2a and IgE antibodies, hypersensitivity reactions and body temperature drop following subcutaneous injection in naive CD-1 mice. The most promising candidate, Bet v 1 COPs anchored to virosomes with membrane-incorporated TLR4 agonist (Vir.A-Bet v 1 COPs), was further evaluated by the sublingual route in a therapeutic setting in BALB/c mice with birch pollen-induced allergic asthma. Airway hyperresponsiveness, pro-inflammatory cells in bronchoalveolar lavages and polarization of Th cells in the lungs and spleen were then assessed.

RESULTS

Both types of adjuvanted virosomes coupled to Bet v 1 COPs triggered a boosted Th1 immunity. Given a more favourable safety profile, Vir.A-Bet v 1 COPs were further evaluated and shown to able to fully reverse asthma symptoms and lung inflammation in a sublingual therapeutic model of birch pollen allergy.

CONCLUSIONS AND CLINICAL RELEVANCE

We report herein for the first time on the capacity of a novel and safe presentation platform, that is virosomes with membrane-integrated TLR4 agonist, to improve dramatically sublingual AIT efficacy in a murine model due to its intrinsic dual properties of targeting and stimulating to further promote anti-allergic immune responses. As such, our study paves the ground for further clinical development of this allergen presentation platform for patients suffering from respiratory allergies.

The Immune System and Its Contribution to Variability in Regenerative Medicine

The immune system plays a critical role in directing tissue repair and regeneration outcomes. Tissue engineering technologies that are designed to promote new tissue growth will therefore be impacted by immune factors that are present in patients both locally at the site of intervention and systemically. The immune state of patients can be influenced by many factors, including infection, nutrition, and other disease comorbidities. As a result, the immune state is highly variable and may be a source of variability in tissue-engineered products in the clinic, which is not found in preclinical models. In this review, we will summarize key immune cells and evidence of their activity in tissue repair and potential in tissue engineering systems. We also discuss how clinical translation of tissue engineering strategies, in particular stem cells, helped elucidate the importance of the immune system. With increased understanding of the immune system's role in repair and tissue engineering systems, it will likely become a therapeutic target and component of future therapies.

The Role of Der p 23 Sensitization: An Analysis of 474 Patients Sensitized to Mite

INTRODUCTION

House dust mite contains several allergen components and causes perennial allergy. Lately, a new major allergen, Der p 23, was described with relatively high sensitization rates in different European Countries. In addition, Der p 23 is supposed to cause asthmatic disease.

OBJECTIVE

We would like to question the prevalence and clinical impact of specific immunoglobulin E to Der p 23 in a large patient sample in southern Bavaria, Germany.

METHODS

474 patients from southern Bavaria, who visited the allergy department within the Department of Oto-Rhino-Laryngology of a university hospital, with sensitization to Dermatophagoides pteronyssinus were retrospectively compared regarding their sensitization profile to Der p 1, Der p 2, and Der p 23 and their clinical characteristics.

RESULTS

Among D. pteronyssinus-sensitized patients, the overall sensitization rate to Der p 23 was 42% in southern Bavaria. Most likely, patients were simultaneously sensitized to Der p 1, Der p 2, and Der p 23. Der p 23-sensitized patients reported more frequently asthma and showed higher prevalence of poly-sensitization towards 3 additional allergen groups and higher prevalence of double-sensitization to Der p 1 and Der p 2 compared to patients with missing sensitization to Der p 23. Considering the results of allergen provocation tests, neither IgE sensitization against Der p 23 nor levels of specific immunoglobulin E to Der p 23 allow a clear prediction of the clinical relevance of the sensitization.

CONCLUSION

With a sensitization rate of 42%, Der p 23 closely misses the criterion of a major allergen in our southern Bavarian patient collective. A higher prevalence of polysensitization and self-reported asthma was the only clinical feature found in Der p 23-sensitized patients.

Molecular diagnosis for allergen immunotherapy

The extensive use of allergen molecules in birth cohort studies revealed that atopic sensitization is a sequential IgE response to distinct non-cross-reacting molecules from the same allergenic source (ie, molecular spreading), starting with an initiator molecule. This phenomenon reaches different degrees of progression (monomolecular, oligomolecular, and polymolecular) according to the individual atopic propensity and allergen exposure, thus producing an extreme heterogeneity of IgE sensitization profiles in patient populations. In patients with allergic rhinitis, the broader the IgE molecular sensitization profile, the greater is the risk of asthma and other allergic comorbidities, such as oral allergy syndrome. Hence it has been proposed to anticipate immunologic intervention at disease onset (early allergen immunotherapy) or even earlier during the preclinical sensitization stage (allergen immunoprophylaxis). Diagnostic algorithms based on singleplex or multiplex molecular IgE tests allow the discrimination of genuine from cross-reacting sensitization and the selection of the right extracts for allergen immunotherapy composition. Patients with extreme molecular poly-sensitization and greater risk of asthma or other IgE-mediated comorbidities, can be easily identified by means of allergen microarray or macroarray procedures and might benefit from anti-IgE treatment. IgE molecular tests have opened the era of precision allergology, and their routine use should aim at cost-effectiveness, according to the principles of the Choosing Wisely initiative.

Predictive in silico binding algorithms reveal HLA specificities and autoallergen peptides associated with atopic dermatitis

Atopic dermatitis (AD) is a skin disease that results from a combination of skin barrier dysfunction and immune dysregulation. The immune dysregulation is often associated with IgE sensitivity. There is also evidence that autoallergens Hom s 1, 2, 3, and 4 play a role in AD; it is possible that patients with specific HLA subtypes are predisposed to autoreactivity due to increased presentation of autoallergen peptides. The goal of our study was to use in silico epitope prediction platforms as an approach to identify HLA subtypes that may preferentially bind autoallergen peptides and are thus candidates for further study. Considering the previously described association of DRB1 alleles with AD and progression of disease, emphasis was placed on DRB1. Certain DRB1 alleles (08:04, 11:01, and 11:04) were identified by both algorithms to bind a significant percent of the generated autoallergen peptides. Conversely, autoallergen core peptide sequences FRQLSHRFH and IRAKLRLQA (Hom s 1), IRKSKNILF (Hom s 2), FKWVPVTDS and MAAIEKVRK (Hom s 3), and FRYFATLKV (Hom s 4) were predicted to bind many DRB1 alleles and, thus, may play a role in the pathogenesis of AD. Our findings provide candidate DRB1 alleles and autoallergen epitopes that will guide future studies exploring the relationship between DRB1 subtype and autoreactivity in AD. A similar approach can be used for any antigen that has been associated with an IgE response and AD.

Dynamics Rationalize Proteolytic Susceptibility of the Major Birch Pollen Allergen Bet v 1

Proteolytic susceptibility during endolysosomal degradation is decisive for allergic sensitization. In the major birch pollen allergen Bet v 1 most protease cleavage sites are located within its secondary structure elements, which are inherently inaccessible to proteases. The allergen thus must unfold locally, exposing the cleavage sites to become susceptible to proteolysis. Hence, allergen cleavage rates are presumed to be linked to their fold stability, i.e., unfolding probability. Yet, these locally unfolded structures have neither been captured in experiment nor simulation due to limitations in resolution and sampling time, respectively. Here, we perform classic and enhanced molecular dynamics (MD) simulations to quantify fold dynamics on extended timescales of Bet v 1a and two variants with higher and lower cleavage rates. Already at the nanosecond-timescale we observe a significantly higher flexibility for the destabilized variant compared to Bet v 1a and the proteolytically stabilized mutant. Estimating the thermodynamics and kinetics of local unfolding around an initial cleavage site, we find that the Bet v 1 variant with the highest cleavage rate also shows the highest probability for local unfolding. For the stabilized mutant on the other hand we only find minimal unfolding probability. These results strengthen the link between the conformational dynamics of allergen proteins and their stability during endolysosomal degradation. The presented approach further allows atomistic insights in the conformational ensemble of allergen proteins and provides probability estimates below experimental detection limits.

An ecological framework of neophobia: from cells to organisms to populations

Neophobia is the fear of novel stimuli or situations. This phenotype has recently received much ecological attention, primarily in the context of decision making. Here, we explore neophobia across biological levels of organisation, first describing types of neophobia among animals and the underlying causes of neophobia, highlighting high levels of risk and uncertainty as key drivers. We place neophobia in the framework of Error Management Theory and Signal Detection Theory, showing how increases in overall risk and uncertainty can lead to costly non-responses towards novel threats unless individuals lower their response threshold and become neophobic. We then discuss how neophobic behaviour translates into population and evolutionary consequences before introducing neophobia-like processes at the cellular level, where some phenomena such as allergy and autoimmunity can parallel neophobic behaviour. Finally, we discuss neophobia attenuation, considering how a sudden change in the environment from dangerous to safe can lead to problematic over-responses (i.e. the 'maladaptive defensive carry-over' hypothesis), and discuss treatment methods for such over-responses. We anticipate that bridging the concept of neophobia with a process-centered perspective can facilitate a transfer of insight across organisational levels.

Recent Progress in Polyhydroxyalkanoates-Based Copolymers for Biomedical Applications

In recent years, naturally biodegradable polyhydroxyalkanoate (PHA) monopolymers have become focus of public attentions due to their good biocompatibility. However, due to its poor mechanical properties, high production costs, and limited functionality, its applications in materials, energy, and biomedical applications are greatly limited. In recent years, researchers have found that PHA copolymers have better thermal properties, mechanical processability, and physicochemical properties relative to their homopolymers. This review summarizes the synthesis of PHA copolymers by the latest biosynthetic and chemical modification methods. The modified PHA copolymer could greatly reduce the production cost with elevated mechanical or physicochemical properties, which can further meet the practical needs of various fields. This review further summarizes the broad applications of modified PHA copolymers in biomedical applications, which might shred lights on their commercial applications.

Adjuvants as Delivery Systems in Antigen-Specific Immunotherapies

Combining autoantigens with immune-modulating drugs has emerged as an attractive approach to selectively reinstate tolerance in autoimmune diseases. The disparate properties of autoantigens and small-molecule immunosuppressants commonly used to treat autoimmune diseases can confound efforts to co-deliver these therapies. However, both components may be co-delivered with adjuvants which have been successful in delivering antigens to immune cells. We evaluated several common adjuvants as vehicles to co-deliver a model antigen and immunosuppressant, ovalbumin (OVA) and dexamethasone (DEX), respectively. Formulations were developed, and the release of DEX from adjuvants was investigated. Next, the effect of adjuvant, DEX, and OVA was tested in vitro using a DC line. A MF59-analog (MF59a) formulation was advanced to more sophisticated co-culture studies using OVA-primed bone marrow-derived dendritic cells and splenocytes or T-cells from OT-II mice. Most of these studies indicated MF59a-based antigen-specific immunotherapies could diminish the markers of inflammation associated with OVA recognition. We rationalized MF59a co-delivery of antigen and drug could reduce the risk of side effects typically associated with these drugs and reinstate immune tolerance, thus prompting continued investigation of emulsion adjuvants as delivery vehicles for antigen-specific immunotherapy of autoimmune diseases.

SPADE web service for prediction of allergen IgE epitopes

The specific interaction of allergens with IgE antibodies and the allergen mediated cross-linking of receptor-bound IgE are key events of allergic diseases. The elucidation of the IgE binding sites (the epitopes) on the allergen surface is an important goal of allergy research. Only few allergen-specific IgE epitopes have been determined experimentally to date. Epitope prediction methods represent a viable alternative to experimental methods and have worked well with linear epitopes. However, as most IgE epitopes are of conformational and/or discontinuous nature sequence based prediction methods have had limited success in these cases. Here, we present the web server of the program SPADE (https://spade.uni-graz.at), which is the server implementation of a previously published program (1). In this approach we utilize the structural homology of cross-reactive allergens combined with the immunological cross-reactivity data for the discrimination of putative IgE-binding sites from non-cross-reactive surface patches. The method, although predictive, does not rely on machine-learning algorithms and does not require training data. The SPADE server features an easy-to-use interface, an automated pipeline consisting of third-party, as well as own, newly developed routines and a comprehensive output page.

NFκB- and MAP-Kinase Signaling Contribute to the Activation of Murine Myeloid Dendritic Cells by a Flagellin A:Allergen Fusion Protein

Fusion proteins incorporating the TLR5-ligand flagellin are currently undergoing clinical trials as vaccine candidates for many diseases. We recently reported a flagellin:allergen fusion protein containing the TLR5-ligand flagellin A (FlaA) from Listeria monocytogenes and the major birch pollen allergen Bet v 1 (rFlaA:Betv1) to prevent allergic sensitization in an experimental mouse model. This study analyzes the signaling pathways contributing to rFlaA:Betv1-mediated pro- and anti-inflammatory cytokine secretion and cell metabolism in myeloid dendritic cells (mDCs) in vitro. The influence of mammalian target of rapamycin (mTOR)-, NFκB-, and MAP kinase (MAPK)-signaling on cytokine secretion and metabolic activity of bone marrow (BM)-derived mDCs stimulated with rFlaA:Betv1 were investigated by pre-treatment with either mTOR- (rapamycin), NFκB- (dexamethason, BMS-345541, TPCA-1, triptolide, or BAY-11) or MAPK- (SP600125, U0126, or SB202190) inhibitors, respectively. rFlaA:Betv1-mediated IL-10 secretion as well as activation of mDC metabolism, rather than pro-inflammatory cytokine secretion, were inhibited by rapamycin. Inhibition of NFκB-signaling suppressed rFlaA:Betv1-induced IL-12, while inhibition of MAPK-signaling dose-dependently suppressed rFlaA:Betv1-induced IL-10 as well as pro-inflammatory IL-6 and TNF-α production. Notably, with the exception of a partial JNK-dependency, rFlaA:Betv1-mediated effects on mDC metabolism were mostly NFκB- and MAPK-independent. Therefore, MAPK-mediated activation of both NFκB- and mTOR-signaling likely is a key pathway for the production of pro- and anti-inflammatory cytokines by flagellin fusion protein vaccines.

Crystal structure and epitope analysis of house dust mite allergen Der f 21

Group 21 and 5 allergens are homologous house dust mite proteins known as mid-tier allergens. To reveal the biological function of group 21 allergens and to understand better the allergenicity of the rDer f 21 allergen, we determined the 1.5 Å crystal structure of rDer f 21 allergen from Dermatophagoides farinae. The rDer f 21 protein consists of a three helical bundle, similar to available structures of group 21 and homologous group 5 allergens. The rDer f 21 dimer forms a hydrophobic binding pocket similar to the one in the Der p 5 allergen, which indicates that both of the homologous groups could share a similar function. By performing structure-guided mutagenesis, we mutated all 38 surface-exposed polar residues of the rDer f 21 allergen and carried out immuno-dot blot assays using 24 atopic sera. Six residues, K10, K26, K42, E43, K46, and K48, which are located in the region between the N-terminus and the loop 1 of rDer f 21 were identified as the major IgE epitopes of rDer f 21. Epitope mapping of all potential IgE epitopes on the surface of the rDer f 21 crystal structure revealed heterogeneity in the sIgE recognition of the allergen epitopes in atopic individuals. The higher the allergen-sIgE level of an individual, the higher the number of epitope residues that are found in the allergen. The results illustrate the clear correlation between the number of specific major epitope residues in an allergen and the sIgE level of the atopic population.

Prevention of allergy by virus-like nanoparticles (VNP) delivering shielded versions of major allergens in a humanized murine allergy model

Background

In high‐risk populations, allergen‐specific prophylaxis could protect from sensitization and subsequent development of allergic disease. However, such treatment might itself induce sensitization and allergies, thus requiring hypoallergenic vaccine formulations. We here characterized the preventive potential of virus‐like nanoparticles (VNP) expressing surface‐exposed or shielded allergens.

Methods

Full‐length major mugwort pollen allergen Art v 1 was selectively targeted either to the surface or to the inner side of the lipid bilayer envelope of VNP. Upon biochemical and immunological analysis, their preventive potential was determined in a humanized mouse model of mugwort pollen allergy.

Results

Virus‐like nanoparticles expressing shielded version of Art v 1, in contrast to those expressing surface‐exposed Art v 1, were hypoallergenic as they hardly induced degranulation of rat basophil leukemia cells sensitized with Art v 1‐specific mouse or human IgE. Both VNP versions induced proliferation and cytokine production of allergen‐specific T cells in vitro. Upon intranasal application in mice, VNP expressing surface‐exposed but not shielded allergen induced allergen‐specific antibodies, including IgE. Notably, preventive treatment with VNP expressing shielded allergen‐protected mice from subsequent sensitization with mugwort pollen extract. Protection was associated with a Th1/Treg‐dominated cytokine response, increased Foxp3⁺ Treg numbers in lungs, and reduced lung resistance when compared to mice treated with empty particles.

Conclusion

Virus‐like nanoparticles represent a novel and versatile platform for the in vivo delivery of allergens to selectively target T cells and prevent allergies without inducing allergic reactions or allergic sensitization.

Design and evaluation of a hypoallergenic peptide-based vaccine for Salsola kali allergy

BACKGROUND

The Salsola kali (S. kali) pollen is one of the most important causes of allergic rhinitis in the deserts and semi-desert areas. Immunotherapy with allergen extracts remains the only available treatment addressing the underlying mechanism of allergy. However, given the low efficacy of this method, it is necessary to find more effective and alternative therapeutic interventions using molecular biology and bioinformatics tools. In this study, a hypoallergenic vaccine was designed on the basis of B-cell epitope approach for S. kali immunotherapy.

METHODS

Using the Immune Epitope Database (IEDB), a 35-mer peptide was selected and chemically conjugated to a keyhole limpet hemocyanin (KLH) molecule. Specific IgG and IgE from immunized BALB/c mice sera against the vaccine (Sal k 1-KLH), S. kali extract and the recombinant protein, rSal k 1, were measured using ELISA. Also, inhibition of IgE by mouse IgG was evaluated using an inhibitory ELISA. Finally, the IgE reactivity and T-cell reactivity of the designed vaccine were evaluated by dot blot assay and MTT assay.

RESULTS

Vaccination with the vaccine produced high levels of protective IgG in mice, which inhibited the binding of patients IgE to recombinant proteins. The result showed that the designed vaccine, unlike the recombinant protein and extract, did not induce T-cell lymphocytes response and also exhibited decreased IgE reactivity.

CONCLUSION

The designed vaccine can be considered as a promising candidate for therapeutic allergen-specific immunotherapy.

The dose response principle from philosophy to modern toxicology: The impact of ancient philosophy and medicine in modern toxicology science

Since ancient times the concept of dose response, from a toxicological perspective, has been a matter of concern. Already by the 8th century BC and over the years, many enlightened people have attempted to interpret this phenomenon, observing and coming across its results and practical implementation through exposure to chemical substances, either from natural or synthetic sources. Nowadays, the environmental exposure of human populations to chemicals in terms of quantity and quality might differ. Nevertheless, dose response still remains an issue joining hands with scientific and technological progress. The aim of the present review is not only to briefly recount the history of the dose response concept, from ancient time theories to novel approaches, but also to draw the outline of challenges and requirements toxicology science needs to fulfill.

Isolation of a high-affinity Bet v 1-specific IgG-derived ScFv from a subject vaccinated with hypoallergenic Bet v 1 fragments

Background

Recombinant hypoallergenic allergen derivatives have been used in clinical immunotherapy studies, and clinical efficacy seems to be related to the induction of blocking IgG antibodies recognizing the wild‐type allergens. However, so far no treatment‐induced IgG antibodies have been characterized.

Objective

To clone, express, and characterize IgG antibodies induced by vaccination with two hypoallergenic recombinant fragments of the major birch pollen allergen, Bet v 1 in a nonallergic subject.

Methods

A phage‐displayed combinatorial single‐chain fragment (ScFv) library was constructed from blood of the immunized subject and screened for Bet v 1‐reactive antibody fragments. ScFvs were tested for specificity and cross‐reactivity to native Bet v 1 and related pollen and food allergens, and epitope mapping was performed. Germline ancestor genes of the antibody were analyzed with the ImMunoGeneTics (IMGT) database. The affinity to Bet v 1 and cross‐reactive allergens was determined by surface plasmon resonance measurements. The ability to inhibit patients’ IgE binding to ELISA plate‐bound allergens and allergen‐induced basophil activation was assessed.

Results

A combinatorial ScFv library was obtained from the vaccinated donor after three injections with the Bet v 1 fragments. Despite being almost in germline configuration, ScFv (clone H3‐1) reacted with high affinity to native Bet v 1 and homologous allergens, inhibited allergic patients’ polyclonal IgE binding to Bet v 1, and partially suppressed allergen‐induced basophil activation.

Conclusion

Immunization with unfolded hypoallergenic allergen derivatives induces high‐affinity antibodies even in nonallergic subjects which recognize the folded wild‐type allergens and inhibit polyclonal IgE binding of allergic patients.

Next-Generation of Allergen-Specific Immunotherapies: Molecular Approaches

PURPOSE OF REVIEW

The aim of this article is to discuss how allergen-specific immunotherapy (AIT) can be improved through molecular approaches. We provide a summary of next-generation molecular AIT approaches and of their clinical evaluation. Furthermore, we discuss the potential of next generation molecular AIT forms for the treatment of severe manifestations of allergy and mention possible future molecular strategies for the secondary and primary prevention of allergy.

RECENT FINDINGS

AIT has important advantages over symptomatic forms of allergy treatment but its further development is limited by the quality of the therapeutic antigen preparations which are derived from natural allergen sources. The field of allergy diagnosis is currently undergoing a dramatic improvement through the use of molecular testing with defined, mainly recombinant allergens which allows high-resolution diagnosis. Several studies demonstrate that molecular testing in early childhood can predict the development of symptomatic allergy later on in life. Clinical studies indicate that molecular AIT approaches have the potential to improve therapy of allergic diseases and may be used as allergen-specific forms of secondary and eventually primary prevention for allergy.

Genetic restriction of antigen-presentation dictates allergic sensitization and disease in humanized mice

BACKGROUND

Immunoglobulin(Ig)E-associated allergies result from misguided immune responses against innocuous antigens. CD4+ T lymphocytes are critical for initiating and perpetuating that process, yet the crucial factors determining whether an individual becomes sensitized towards a given allergen remain largely unknown.

OBJECTIVE

To determine the key factors for sensitization and allergy towards a given allergen.

METHODS

We here created a novel human T cell receptor(TCR) and human leucocyte antigen (HLA)-DR1 (TCR-DR1) transgenic mouse model of asthma, based on the human-relevant major mugwort (Artemisia vulgaris) pollen allergen Art v 1 to examine the critical factors for sensitization and allergy upon natural allergen exposure via the airways in the absence of systemic priming and adjuvants.

RESULTS

Acute allergen exposure led to IgE-independent airway hyperreactivity (AHR) and T helper(Th)2-prone lung inflammation in TCR-DR1, but not DR1, TCR or wildtype (WT) control mice, that was alleviated by prophylactic interleukin(IL)-2-αIL-2 mAb complex-induced expansion of Tregs. Chronic allergen exposure sensitized one third of single DR1 transgenic mice, however, without impacting on lung function. Similar treatment led to AHR and Th2-driven lung pathology in >90% of TCR-DR1 mice. Prophylactic and therapeutic expansion of Tregs with IL-2-αIL-2 mAb complexes blocked the generation and boosting of allergen-specific IgE associated with chronic allergen exposure.

CONCLUSIONS

We identify genetic restriction of allergen presentation as primary factor dictating allergic sensitization and disease against the major pollen allergen from the weed mugwort, which frequently causes sensitization and disease in humans. Furthermore, we demonstrate the importance of the balance between allergen-specific T effector and Treg cells for modulating allergic immune responses.

Molecular Aspects of Allergens and Allergy

Immunoglobulin E (IgE)-associated allergy is the most common immune disorder. More than 30% of the population suffer from symptoms of allergy which are often severe, disabling, and life threatening such as asthma and anaphylaxis. Population-based birth cohort studies show that up to 60% of the world population exhibit IgE sensitization to allergens, of which most are protein antigens. Thirty years ago the first allergen-encoding cDNAs have been isolated. In the meantime, the structures of most of the allergens relevant for disease in humans have been solved. Here we provide an update regarding what has been learned through the use of defined allergen molecules (i.e., molecular allergology) and about mechanisms of allergic disease in humans. We focus on new insights gained regarding the process of sensitization to allergens, allergen-specific secondary immune responses, and mechanisms underlying allergic inflammation and discuss open questions. We then show how molecular forms of diagnosis and specific immunotherapy are currently revolutionizing diagnosis and treatment of allergic patients and how allergen-specific approaches may be used for the preventive eradication of allergy.

Conformational IgE Epitope Mapping of Der p 2 and the Evaluations of Two Candidate Hypoallergens for Immunotherapy

Epitope mapping of Der p 2, a clinically important dust-mite allergen is the first step in designing immunotherapy hypoallergen vaccine candidates. Twenty-one single alanine mutants of Der p 2 were generated and their secondary structure was analysed using circular dichroism spectra. Only one mutant, K96A resulted in a misfolded protein. All mutants were tested for serum IgE reactivity using serum from dust mite allergic individuals by immuno dot-blots. Mutations to five residues, N10, E25, K77, K96 and E102 consistently showed reduced IgE reactions compared to wild-type Der p 2, and therefore these residues constitute the major IgE epitopes of Der p 2. Two mutants with consistent low IgE binding, K96A and E102A, were subsequently evaluated as hypoallergen candidates. IgG antibodies raised in mice against both mutants could inhibit human IgE-binding to WT Der p 2. Both mutants had intact T-cell epitopes as they were able to stimulate peripheral blood mononuclear cell proliferation similar to WT Der p 2. However, a switch in Th1:Th2 cytokine profile was not observed. In summary, we have identified the major conformational epitopes of Der p 2, and evaluated two Der p 2 hypoallergen vaccine candidates for immunotherapy.

Conjugation of wildtype and hypoallergenic mugwort allergen Art v 1 to flagellin induces IL-10-DC and suppresses allergen-specific TH2-responses in vivo

Allergies to weed pollen including members of the Compositae family, such as mugwort, ragweed, and feverfew are spreading worldwide. To efficiently treat these newly arising allergies, allergen specific immunotherapy needs to be improved. Therefore, we generated novel vaccine candidates consisting of the TLR5-ligand Flagellin A from Listeria and the major mugwort allergen Art v 1 including either the wild type Art v 1 sequence (rFlaA:Artv1) or a hypoallergenic variant (rFlaA:Artv1^hyp) with reduced IgE-binding capacity. Immune modulating capacity of these constructs and respective controls was evaluated in vitro and in vivo. Incorporation of hypoallergenic Art v 1 derivative did not interfere with the resulting fusion proteins’ immune stimulatory capacity. Both rFlaA:Artv1 and rFlaA:Artv1^hyp induced a prominent, mTOR-dependent, IL-10 secretion from murine dendritic cells, and suppressed allergen-specific TH2-cytokine secretion in vitro and in vivo. Both conjugates retained the capacity to induce rFlaA-specific antibody responses while efficiently inducing production of Art v 1-specific IgG1 and IgG2a antibodies in mice. Interestingly, only the suppression of TH2-cytokine secretion by rFlaA:Artv1 (but not rFlaA:Artv1^hyp) was paralleled by a strong secretion of IFN-γ. In summary, we provided evidence that incorporating hypoallergens into flagellin:allergen fusion proteins is a suitable strategy to further improve these promising vaccine candidates.

Natural Evolution of IgE Responses to Mite Allergens and Relationship to Progression of Allergic Disease: a Review

PURPOSE OF REVIEW

Allergenic molecules of the house dust mite (HDM) are crucially important indoor allergens, contributing to allergic rhinitis and asthma around the globe. In the past years, recombinant molecules for diagnostics opened new pathways to investigate individual sensitization profiles and new chances for the prevention and treatment of HDM allergy. This review summarizes the latest findings on the evolution of IgE responses towards mite allergens.

RECENT FINDINGS

Several cross-sectional and longitudinal studies confirmed the role of Der p 1 and Der p 2 as major allergenic proteins of the HDM. A newly identified player is the major allergen Der p 23. Apart from identifying the early sensitization towards this molecule as a risk factor for asthma in school age, a recent longitudinal study described sensitization patterns showing that the production of IgE usually starts towards a group of initiator proteins and may stay monomolecular or expand to an oligo- or even polymolecular stage. This phenomenon also correlates to clinical symptoms. A relation between a broad sensitization pattern and symptom severity has also been shown cross-sectionally. Individual sensitization profiles towards HDM allergens provide important information to evaluate a patient's current stage and risk for clinical symptoms. This knowledge paves the way for an early and adequate prevention and/or treatment.

Biotunable Nanoplasmonic Filter on Few-Layer MoS2 for Rapid and Highly Sensitive Cytokine Optoelectronic Immunosensing

Monitoring of the time-varying immune status of a diseased host often requires rapid and sensitive detection of cytokines. Metallic nanoparticle-based localized surface plasmon resonance (LSPR) biosensors hold promise to meet this clinical need by permitting label-free detection of target biomolecules. These biosensors, however, continue to suffer from relatively low sensitivity as compared to conventional immunoassay methods that involve labeling processes. Their response speeds also need to be further improved to enable rapid cytokine quantification for critical care in a timely manner. In this paper, we report an immunobiosensing device integrating a biotunable nanoplasmonic optical filter and a highly sensitive few-layer molybdenum disulfide (MoS₂) photoconductive component, which can serve as a generic device platform to meet the need of rapid cytokine detection with high sensitivity. The nanoplasmonic filter consists of anticytokine antibody-conjugated gold nanoparticles on a SiO₂ thin layer that is placed 170 μm above a few-layer MoS₂ photoconductive flake device. The principle of the biosensor operation is based on tuning the delivery of incident light to the few-layer MoS₂ photoconductive flake thorough the nanoplasmonic filter by means of biomolecular surface binding-induced LSPR shifts. The tuning is dependent on cytokine concentration on the nanoplasmonic filter and optoelectronically detected by the few-layer MoS₂ device. Using the developed optoelectronic biosensor, we have demonstrated label-free detection of IL-1β, a pro-inflammatory cytokine, with a detection limit as low as 250 fg/mL (14 fM), a large dynamic range of 10⁶, and a short assay time of 10 min. The presented biosensing approach could be further developed and generalized for point-of-care diagnosis, wearable bio/chemical sensing, and environmental monitoring.

Recombinant allergy vaccines based on allergen-derived B cell epitopes

Immunoglobulin E (IgE)-associated allergy is the most common immunologically-mediated hypersensitivity disease. It affects more than 25% of the population. In IgE-sensitized subjects, allergen encounter can causes a variety of symptoms ranging from hayfever (allergic rhinoconjunctivitis) to asthma, skin inflammation, food allergy and severe life-threatening anaphylactic shock. Allergen-specific immunotherapy (AIT) is based on vaccination with the disease-causing allergens. AIT is an extremely effective, causative and disease-modifying treatment. However, administration of natural allergens can cause severe side effects and the quality of natural allergen extracts limits its application. Research in the field of molecular allergen characterization has allowed deciphering the molecular structures of the disease-causing allergens and it has become possible to engineer novel molecular allergy vaccines which precisely target the mechanisms of the allergic immune response and even appear suitable for prophylactic allergy vaccination. Here we discuss recombinant allergy vaccines which are based on allergen-derived B cell epitopes regarding their molecular and immunological properties and review the results obtained in clinical studies with this new type of allergy vaccines.

Transcutaneous pollinosis immunotherapy using a solid-in-oil nanodispersion system carrying T cell epitope peptide and R848

Antigen‐specific immunotherapy is the only curative approach for the treatment of allergic diseases such as Japanese cedar pollinosis. Immunotherapy using a T cell epitope vaccine in combination with the adjuvant R848 is of particular interest as a safe and effective approach to treat allergic diseases. Herein, we propose a simple and easy to handle vaccine administration method using the original solid‐in‐oil (S/O) nanodispersion system that permeates through the skin. The S/O nanodispersion system is composed of nanoparticles of hydrophilic molecules surrounded with hydrophobic surfactants that are dispersed in an oil vehicle. The system has potential to carry and deliver both hydrophilic and hydrophobic bioactives. Hydrophilic T cell epitope peptide was efficiently delivered through mouse skin using the S/O nanodispersion system and lowered antigen‐specific IgE levels in pollinosis model mice. Addition of the hydrophobic adju1vant R848 significantly lowered the antibody secretion and shifted the Th1/Th2‐balance toward Th1‐type immunity in the model mice, showing the potential to alleviate Japanese cedar pollinosis.

Network pharmacology-based identification of key pharmacological pathways of Yin-Huang-Qing-Fei capsule acting on chronic bronchitis

For decades in China, the Yin-Huang-Qing-Fei capsule (YHQFC) has been widely used in the treatment of chronic bronchitis, with good curative effects. Owing to the complexity of traditional Chinese herbal formulas, the pharmacological mechanism of YHQFC remains unclear. To address this problem, a network pharmacology-based strategy was proposed in this study. At first, the putative target profile of YHQFC was predicted using MedChem Studio, based on structural and functional similarities of all available YHQFC components to the known drugs obtained from the DrugBank database. Then, an interaction network was constructed using links between putative YHQFC targets and known therapeutic targets of chronic bronchitis. Following the calculation of four topological features (degree, betweenness, closeness, and coreness) of each node in the network, 475 major putative targets of YHQFC and their topological importance were identified. In addition, a pathway enrichment analysis based on the Kyoto Encyclopedia of Genes and Genomes pathway database indicated that the major putative targets of YHQFC are significantly associated with various pathways involved in anti-inflammation processes, immune responses, and pathological changes caused by asthma. More interestingly, eight major putative targets of YHQFC (interleukin [IL]-3, IL-4, IL-5, IL-10, IL-13, FCER1G, CCL11, and EPX) were demonstrated to be associated with the inflammatory process that occurs during the progression of asthma. Finally, a molecular docking simulation was performed and the results exhibited that 17 pairs of chemical components and candidate YHQFC targets involved in asthma pathway had strong binding efficiencies. In conclusion, this network pharmacology-based investigation revealed that YHQFC may attenuate the inflammatory reaction of chronic bronchitis by regulating its candidate targets, which may be implicated in the major pathological processes of the asthma pathway.

Treatment of allergic rhinitis with acupoint herbal plaster: an oligonucleotide chip analysis

Background

Allergic rhinitis is regarded as an imbalanced Th1/Th2 cell-mediated response. The present study used microarray analysis to compare gene expression levels between allergic rhinitis patients before and after a series of acupoint herbal plaster applications.

Methods

In this experimental pilot study, volunteers experiencing sneezing, runny nose, and congestion for more than 9 months in the year following initial diagnoses were included after diagnostic confirmation by otolaryngologists to exclude patients with sinusitis and nasal polyps. Patients with persistent allergic rhinitis each received four acupoint herbal plaster treatments applied using the moxibustion technique. Clinical outcomes were evaluated using the Rhinitis Quality of Life Questionnaire (RQLQ). Peripheral blood samples were analyzed using an ImmunoCAP Phadiatop test, and patients were classified as phadiatop (Ph)-positive or -negative. Microarray results were analyzed for genes that were differentially expressed between (1) Ph-positive and -negative patients treated with herbal plaster; and (2) before and after herbal plaster treatment in the Ph-positive patient group. Unsupervised and supervised methods were used for gene-expression data analysis.

Results

Nineteen Ph-positive and four Ph-negative participants with persistent allergic rhinitis were included in the study. RQLQ results indicated that the 19 Ph-positive volunteers experienced improvement in six of seven categories following acupoint herbal plaster treatments, whereas the four Ph-negative participants reported improvement in only two categories. Hierarchical clustering and principle component analysis of the gene expression profiles of Ph-positive and –negative participants indicated the groups exhibited distinct physiological responses to acupoint herbal treatment. Evaluation of gene networks using MetaCore identified that the “Immune response_IL-13 signaling via JAK-STAT” and the “Inflammation_Interferon signaling” were down- and up-regulated, respectively, among Ph-positive subjects.

Conclusions

In this preliminary study, we find that the IL-13 immune response via JAK-STAT signaling and interferon inflammation signaling were down- and upregulated, respectively, in the Ph-positive group. Further studies are required to verify these pathways in Ph-positive patients, and to determine the mechanism of such pathway dysregulation.

Trial registration

ClinicalTrials.gov: NCT02486159. Registered 30 Jun 2015.

Evolution and predictive value of IgE responses toward a comprehensive panel of house dust mite allergens during the first 2 decades of life

BACKGROUND

The evolution of the IgE response to the numerous allergen molecules of Dermatophagoides pteronyssinus is still unknown.

OBJECTIVES

We sought to characterize the evolutionary patterns of the IgE response to 12 molecules of D pteronyssinus from birth to adulthood and to investigate their determinants and clinical relevance.

METHODS

We investigated the clinical data and sera of 722 participants in the German Multicenter Allergy Study, a birth cohort started in 1990. Diagnoses of current allergic rhinitis (AR) related to mite allergy and asthma were based on yearly interviews at the ages of 1 to 13 years and 20 years. IgE to the extract and 12 molecules of D pteronyssinus were tested by means of ImmunoCAP and microarray technology, respectively, in sera collected at ages 1, 2, 3, 5, 6, 7, 10, 13, and 20 years. Exposure to mites at age 6 and 18 months was assessed by measuring Der p 1 weight/weight concentration in house dust.

RESULTS

One hundred ninety-one (26.5%) of 722 participants ever had IgE to D pteronyssinus extract (≥0.35 kU_A/L). At age 20 years, their IgE recognized most frequently Der p 2, Der p 1, and Der p 23 (group A molecules; prevalence, >40%), followed by Der p 5, Der p 7, Der p 4, and Der p 21 (group B molecules; prevalence, 15% to 30%) and Der p 11, Der p 18, clone 16, Der p 14, and Der p 15 (group C molecules; prevalence, <10%). IgE sensitization started almost invariably with group A molecules and expanded sequentially first to group B and finally to group C molecules. Early IgE sensitization onset, parental hay fever, and higher exposure to mites were associated with a broader polymolecular IgE sensitization pattern. Participants reaching the broadest IgE sensitization stage (ie, ABC) had significantly higher risk of mite-related AR and asthma than unsensitized participants. IgE to Der p 1 or Der p 23 at age 5 years or less predicted asthma at school age.

CONCLUSIONS

Parental hay fever and early exposure to D pteronyssinus allergens promote IgE polysensitization to several D pteronyssinus molecules, which in turn predicts current mite-related AR and current/future asthma. These results might inspire predictive algorithms and prevention strategies against the progression of IgE sensitization to mites toward AR and asthma.

Creation of an engineered APC system to explore and optimize the presentation of immunodominant peptides of major allergens

We have generated engineered APC to present immunodominant peptides derived from the major aero-allergens of birch and mugwort pollen, Bet v 1142-153 and Art v 125-36, respectively. Jurkat-based T cell reporter lines expressing the cognate allergen-specific T cell receptors were used to read out the presentation of allergenic peptides on the engineered APC. Different modalities of peptide loading and presentation on MHC class II molecules were compared. Upon exogenous loading with allergenic peptides, the engineered APC elicited a dose-dependent response in the reporter T cells and the presence of chemical loading enhancers strongly increased reporter activation. Invariant chain-based MHC class II targeting strategies of endogenously expressed peptides resulted in stronger activation of the reporters than exogenous loading. Moreover, we used Bet v 1 as model allergen to study the ability of K562 cells to present antigenic peptides derived from whole proteins either taken up or endogenously expressed as LAMP-1 fusion protein. In both cases the ability of these cells to process and present peptides derived from whole proteins critically depended on the expression of HLA-DM. We have identified strategies to achieve efficient presentation of allergenic peptides on engineered APC and demonstrate their use to stimulate T cells from allergic individuals.

Solid-in-oil nanodispersions for transdermal drug delivery systems

Transdermal administration of drugs has advantages over conventional oral administration or administration using injection equipment. The route of administration reduces the opportunity for drug evacuation before systemic circulation, and enables long-lasting drug administration at a modest body concentration. In addition, the skin is an attractive route for vaccination, because there are many immune cells in the skin. Recently, solid-in-oil nanodisperison (S/O) technique has demonstrated to deliver cosmetic and pharmaceutical bioactives efficiently through the skin. S/O nanodispersions are nanosized drug carriers designed to overcome the skin barrier. This review discusses the rationale for preparation of efficient and stable S/O nanodispersions, as well as application examples in cosmetic and pharmaceutical materials including vaccines. Drug administration using a patch is user-friendly, and may improve patient compliance. The technique is a potent transcutaneous immunization method without needles.

The allergen Mus m 1.0102: Dissecting the relationship between molecular conformation and allergenic potency

BACKGROUND

The species Mus musculus experiences an obligate proteinuria: predominant are the Major Urinary Proteins (MUPs), that, collectively known as the major mouse allergen Mus m 1, are among the most important aeroallergens for mouse allergic patients. The production of a soluble and stable hypoallergenic form of Mus m 1 is essential for the development of immunotherapeutic protocols to treat allergic symptoms.

METHODS

We introduced the substitution C138S in recombinant Mus m 1.0102, an allergenic isoform of Mus m 1. Solubility, conformation, stability and ability to refold after chemical denaturation were investigated with dynamic light scattering, circular dichroism, fluorescence and NMR spectroscopy. An in vitro degranulation assay was used to evaluate the protein allergenic potential, and compare it with Mus m 1.0102 and with an hypoallergenic variant bearing the substitution Y120A.

RESULTS

Mus m 1.0102-C138S retains a native-like fold revealing, however, local conformational alterations that influence some of its physical and allergenic properties: it is monodispersed, thermostable up to 56°C, able to reversibly unfold and it exhibits an enhanced allergenicity.

CONCLUSIONS

The unique free thiol group affects the solution structural stability of the native protein. Because the mutant C138S does not aggregate over time it is a good lead protein to develop diagnostic and therapeutic applications.

GENERAL SIGNIFICANCE

We elucidated the relationship between unfolding reversibility and sulphydryl reactivity. We ascribed the enhanced allergenicity of the mutant C138S to an increased accessibility of its allergenic determinants, an enticing feature to further investigate the structural elements of the allergen-IgE interface.

Immunotherapy With the PreS-based Grass Pollen Allergy Vaccine BM32 Induces Antibody Responses Protecting Against Hepatitis B Infection

Background

We have constructed and clinically evaluated a hypoallergenic vaccine for grass pollen allergy, BM32, which is based on fusion proteins consisting of peptides from the IgE binding sites of the major grass pollen allergens fused to preS (preS1 + preS2), a domain of the hepatitis B virus (HBV) large envelope protein which mediates the viral attachment and entry. Aim of this study was the characterization of the HBV-specific immune response induced by vaccination of allergic patients with BM32 and the investigation of the vaccines' potential to protect against infection with HBV.

Methods

Hepatitis B-specific antibody and T cell responses of patients vaccinated with BM32 were studied using recombinant preS and synthetic overlapping peptides spanning the preS sequence. The specificities of the antibody responses were compared with those of patients with chronic HBV infection. Furthermore, the capacity of BM32-induced antibodies, to inhibit HBV infection was investigated using HepG2-hNTCP cell-based in vitro virus neutralization assays.

Findings

IgG antibodies from BM32-vaccinated but not of HBV-infected individuals recognized the sequence motif implicated in NTCP (sodium-taurocholate co-transporting polypeptide)-receptor interaction of the hepatitis B virus and inhibited HBV infection.

Interpretation

Our study demonstrates that the recombinant hypoallergenic grass pollen allergy vaccine BM32 induces hepatitis B-specific immune responses which protect against hepatitis B virus infection in vitro.

•

BM32 is a recombinant allergy vaccine consisting of the preS domain of the large envelope protein of hepatitis B virus (HBV) and allergen-derived peptides.

•

Vaccination of allergic patients with BM32 induced preS-specific antibodies which inhibit hepatitis B infection in vitro.

•

BM32 may be useful as therapeutic vaccine in HBV-infected patients.

Infection with HBV remains a major cause of morbidity and mortality worldwide. Conventional HBV vaccines, consisting of SHBs particles solely, do not elicit adequate antibody production in 5–10% of vaccines and there is a need for therapeutic HBV vaccines. We have engineered an allergy vaccine which consists of allergen-derived peptides fused to the preS domain of the large envelope protein of HBV. Here we show that vaccination of allergic patients with this vaccine induces antibodies which protect against HBV infection in vitro. The preS-containing allergy vaccine may thus be also useful for therapeutic vaccination of HBV-infected patients.

Small-Molecule Carbohydrate-Based Immunostimulants

In this review, we discuss small-molecule, carbohydrate-based immunostimulants that target Toll-like receptor 4 (TLR-4) and cluster of differentiation 1D (CD1d) receptors. The design and use of these molecules in immunotherapy as well as results from their use in clinical trials are described. How these molecules work and their utilization as vaccine adjuvants are also discussed. Future applications and extensions for the use of these analogues as therapeutic agents will be outlined.

A Fusion Protein Consisting of the Vaccine Adjuvant Monophosphoryl Lipid A and the Allergen Ovalbumin Boosts Allergen-Specific Th1, Th2, and Th17 Responses In Vitro

Background. The detoxified TLR4-ligand Monophosphoryl Lipid A (MPLA) is the first approved TLR-agonist used as adjuvant in licensed vaccines but has not yet been explored as part of conjugated vaccines. Objective. To investigate the immune-modulating properties of a fusion protein consisting of MPLA and Ovalbumin (MPLA : Ova). Results. MPLA and Ova were chemically coupled by stable carbamate linkage. MPLA : Ova was highly pure without detectable product-related impurities by either noncoupled MPLA or Ova. Light scattering analysis revealed MPLA : Ova to be aggregated. Stimulation of mDC and mDC : DO11.10 CD4⁺ TC cocultures showed a stronger activation of both mDC and Ova-specific DO11.10 CD4⁺ TC by MPLA : Ova compared to the mixture of both components. MPLA : Ova induced both strong proinflammatory (IL-1β, IL-6, and TNF-α) and anti-inflammatory (IL-10) cytokine responses from mDCs while also boosting allergen-specific Th1, Th2, and Th17 cytokine secretion. Conclusion. Conjugation of MPLA and antigen enhanced the immune response compared to the mixture of both components. Due to the nonbiased boost of Ova-specific Th2 and Th17 responses while also inducing Th1 responses, this fusion protein may not be a suitable vaccine candidate for allergy treatment but may hold potential for the treatment of other diseases that require a strong stimulation of the host's immune system (e.g., cancer).