Recombinant PreS-fusion protein vaccine for birch pollen and apple allergy

BACKGROUND

IgE cross-sensitization to major birch pollen allergen Bet v 1 and pathogenesis-related (PR10) plant food allergens is responsible for the pollen-food allergy syndrome.

METHODS

We designed a recombinant protein, AB-PreS, consisting of non-allergenic peptides derived from the IgE-binding sites of Bet v 1 and the cross-reactive apple allergen, Mal d 1, fused to the PreS domain of HBV surface protein as immunological carrier. AB-PreS was expressed in E. coli and purified by chromatography. The allergenic and inflammatory activity of AB-PreS was tested using basophils and PBMCs from birch pollen allergic patients. The ability of antibodies induced by immunization of rabbits with AB-PreS and birch pollen extract-based vaccines to inhibit allergic patients IgE binding to Bet v 1 and Mal d 1 was assessed by ELISA.

RESULTS

IgE-binding experiments and basophil activation test revealed the hypoallergenic nature of AB-PreS. AB-PreS induced lower T-cell activation and inflammatory cytokine production in cultured PBMCs from allergic patients. IgG antibodies induced by five injections with AB-PreS inhibited allergic patients' IgE binding to Bet v 1 and Mal d 1 better than did IgG induced by up to 30 injections of six licensed birch pollen allergen extract-based vaccines. Additionally, immunization with AB-PreS induced HBV-specific antibodies potentially protecting from infection with HBV.

CONCLUSION

The recombinant AB-PreS-based vaccine is hypoallergenic and superior over currently registered allergen extract-based vaccines regarding the induction of blocking antibodies to Bet v 1 and Mal d 1 in animals.

Novel adjuvants in allergen-specific immunotherapy: where do we stand?

Type I hypersensitivity, or so-called type I allergy, is caused by Th2-mediated immune responses directed against otherwise harmless environmental antigens. Currently, allergen-specific immunotherapy (AIT) is the only disease-modifying treatment with the potential to re-establish clinical tolerance towards the corresponding allergen(s). However, conventional AIT has certain drawbacks, including long treatment durations, the risk of inducing allergic side effects, and the fact that allergens by themselves have a rather low immunogenicity. To improve AIT, adjuvants can be a powerful tool not only to increase the immunogenicity of co-applied allergens but also to induce the desired immune activation, such as promoting allergen-specific Th1- or regulatory responses. This review summarizes the knowledge on adjuvants currently approved for use in human AIT: aluminum hydroxide, calcium phosphate, microcrystalline tyrosine, and MPLA, as well as novel adjuvants that have been studied in recent years: oil-in-water emulsions, virus-like particles, viral components, carbohydrate-based adjuvants (QS-21, glucans, and mannan) and TLR-ligands (flagellin and CpG-ODN). The investigated adjuvants show distinct properties, such as prolonging allergen release at the injection site, inducing allergen-specific IgG production while also reducing IgE levels, as well as promoting differentiation and activation of different immune cells. In the future, better understanding of the immunological mechanisms underlying the effects of these adjuvants in clinical settings may help us to improve AIT.

Allergen-specific immunotherapy by recombinant Der P1 allergen-derived peptide-based vaccine in an allergic mouse model

AIM

Increased IgE levels have made house dust mite allergens one of the most frequent causes of allergies worldwide. Treatment reduces the IgE antibodies and types two cytokines, namely interleukin-4 (IL-4) and IL-13. Although existing treatments significantly reduce IgE or IL-4/IL-13, they are very costly. This study aimed to construct a recombinant protein derived from rDer p1 peptides in the form of an immunotherapy approach and to measure the response of IgE and IgG antibodies.

METHODS

The proteins were isolated, purified, and evaluated using the SDS-PAGE and Bradford test and confirmed by using Western blot. To evaluate immunotherapy efficiency, 24 BALB/C mice were sensitized intraperitoneally with house dust mites (HDM) adsorbed to Aluminum hydroxide (Alum) and randomly divided into four groups of six: control sensitized, HDM extract, rDer p1, and DpTTDp vaccine. To immunization, four groups of random mice were each treated with phosphate-buffered saline, 100 μg of rDer p1 protein, DpTTDp, or HDM extract, every 3 days. Direct ELISA determined HDM-specific IgG and IgE subclasses. Data were analyzed in SPSS and Graph pad prism software. Values of p < .05 were considered significant.

RESULTS

After immunization of mice, the rDer P1 and recombinant vaccine like HDM extract increased IgG antibody titer and decreased IgE-dependent reactivity in allergic mice to rDer P1. Also, the levels of inflammatory IL-4 and IL-13 cytokines as allergic stimulants decreased.

CONCLUSION

The use of present available recombinant proteins is considered a viable, cost-effective, and long-term option for providing effective HDM allergy immunotherapy vaccines without side effects.

The ICAM-1 ligand HRV-A89 is internalized independently of clathrin-mediated endocytosis and its capsid reaches late endosomes

The human rhinovirus (HRV) A2 is endocytosed by clathrin-mediated endocytosis (CME) bound to the classical LDL receptor and releases its RNA during its transport to late endosomes. Here it is shown that - presumably due to an effect on virus recycling - a low concentration of the CME inhibitor chlorpromazine present during virus internalization (30 min) did not reduce HRV-A2 infection, but strongly inhibited short-time (5 min) endocytosis of HRV-A2. Chlorpromazine had no effect on the colocalization of the ICAM-1 ligand HRV-A89 with early endosomes, excluding CME as the main endocytosis pathway of this virus. As published for HRV-A2 and HRV-A14, HRV-A89 partially colocalized with lysosome-associated membrane protein 2 and the microtubule inhibitor nocodazole did not reduce virus infection when present only during virus internalization. Together with previous work these data suggest that there are no principal differences between endocytosis pathways of ICAM-1-binding rhinoviruses in different cell types.

Antibody Conjugates Bispecific for Pollen Allergens and ICAM-1 with Potential to Prevent Epithelial Allergen Transmigration and Rhinovirus Infection

Allergy and rhinovirus (RV) infections are major triggers for rhinitis and asthma, causing a socioeconomic burden. As RVs and allergens may act synergistically to promote airway inflammation, simultaneous treatment strategies for both causative agents would be innovative. We have previously identified the transmembrane glycoprotein intercellular adhesion molecule 1 (ICAM-1) as an anchor for antibody conjugates bispecific for ICAM-1 and Phleum pratense (Phl p) 2, a major grass pollen allergen, to block allergen transmigration through the epithelial barrier. Since ICAM-1 is a receptor for the major group RVs, we speculated that our bispecific antibody conjugates may protect against RV infection. Therefore, we created antibody conjugates bispecific for ICAM-1 and the major grass pollen allergen Phl p 5 and analyzed their capacity to affect allergen penetration and RV infection. Bispecific antibody conjugates significantly reduced the trans-epithelial migration of Phl p 5 and thus the basolateral Phl p 5 concentration and allergenic activity as determined by humanized rat basophilic leukemia cells and inhibited RV infection of cultured epithelial cells. A reduction in allergenic activity was obtained only through the prevention of allergen transmigration because the Phl p 5-specific IgG antibody did not block the allergen-IgE interaction. Our results indicate the potential of allergen/ICAM-1-specific antibody conjugates as a topical treatment strategy for allergy and RV infections.

Vaccine based on folded receptor binding domain-PreS fusion protein with potential to induce sterilizing immunity to SARS-CoV-2 variants

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the ongoing global COVID-19 pandemic. One possibility to control the pandemic is to induce sterilizing immunity through the induction and maintenance of neutralizing antibodies preventing SARS-CoV-2 from entering human cells to replicate in.

METHODS

We report the construction and in vitro and in vivo characterization of a SARS-CoV-2 subunit vaccine (PreS-RBD) based on a structurally folded recombinant fusion protein consisting of two SARS-CoV-2 Spike protein receptor-binding domains (RBD) fused to the N- and C-terminus of hepatitis B virus (HBV) surface antigen PreS to enable the two unrelated proteins serving as immunologic carriers for each other.

RESULTS

PreS-RBD, but not RBD alone, induced a robust and uniform RBD-specific IgG response in rabbits. Currently available genetic SARS-CoV-2 vaccines induce mainly transient IgG1 responses in vaccinated subjects whereas the PreS-RBD vaccine induced RBD-specific IgG antibodies consisting of an early IgG1 and sustained IgG4 antibody response in a SARS-CoV-2 naive subject. PreS-RBD-specific IgG antibodies were detected in serum and mucosal secretions, reacted with SARS-CoV-2 variants, including the omicron variant of concern and the HBV receptor-binding sites on PreS of currently known HBV genotypes. PreS-RBD-specific antibodies of the immunized subject more potently inhibited the interaction of RBD with its human receptor ACE2 and their virus-neutralizing titers (VNTs) were higher than median VNTs in a random sample of healthy subjects fully immunized with registered SARS-CoV-2 vaccines or in COVID-19 convalescent subjects.

CONCLUSION

The PreS-RBD vaccine has the potential to serve as a combination vaccine for inducing sterilizing immunity against SARS-CoV-2 and HBV by stopping viral replication through the inhibition of cellular virus entry.

Proteomics for Development of Food Allergy Vaccines

Food allergy is a hypersensitivity reaction to food products initiated by immunologic mechanisms, which represents one of the major concerns in food safety. New therapies for food allergies including oral and epicutaneous allergen-specific immunotherapy are required, and B cell epitope-based allergy vaccines are a good promise to improve this field. In this chapter, we describe a workflow for the design of food allergy vaccines using proteomic tools. The strategy is defined based on the characterization of B cell epitopes for a particular food allergen. For that, the workflow comprises five consecutive steps: (1) shotgun proteomics analysis of different protein isoforms for a particular food allergen, (2) downloading all protein sequences for the specific allergen included in UniProtKB database, (3) analysis by protein-based bioinformatics of B cell epitopes, (4) synthesizing of the selected B cell peptide epitopes, and (5) performing of immunoassays using sera from healthy and allergic patients. The results from this method provide a rationale repository of B cell epitopes for the design of new specific immunotherapies for a particular food allergen. The strategy was optimized for all the beta-parvalbumins (β-PRVBs), which are considered as the main fish allergens. Using this workflow, a total of 35 peptides were identified as B cell epitopes, among them the top 4 B cell peptide epitopes that may induce protective immune response were selected as potential peptide vaccine candidates for fish allergy.

Design of peptides with high affinity binding to a monoclonal antibody as a basis for immunotherapy

About half of the US population is sensitized to one or more allergens, as found by a National Health and Nutrition Examination Survey (NHANES). The most common treatment for seasonal allergic responses is the daily use of oral antihistamines, which can control some of the symptoms, but are not effective for nasal congestion, and can be debilitating in many patients. Peptide immunotherapy is a promising new approach to treat allergic airway diseases. The small size of the immunogens cannot lead to an unwanted allergic reaction in sensitized patients, and the production of peptides with sufficient amounts for immunotherapy is time- and cost-effective. However, it is not known what peptides are the most effective for an immunotherapy of allergens. We previously produced a unique monoclonal antibody (mAb) E58, which can inhibit the binding of multiple groups of mAbs and human IgEs from patients affected by the major group 1 allergens of ragweed (Amb a 1) and conifer pollens (Jun a 1, Cup s 1, and Cry j 1). Here, we demonstrated that a combined approach, starting from two linear E58 epitopes of the tree pollen allergen Jun a 1 and the ragweed pollen allergen Amb a 1, and residue modifications suggested by molecular docking calculations and peptide design could identify a large number of high affinity binding peptides. We propose that this combined experimental and computational approach by structural analysis of linear IgE epitopes and peptide design, can lead to potential new candidates for peptide immunotherapy.

Perspectives in Allergen-Specific Immunotherapy: Molecular Evolution of Peptide- and Protein-Based Strategies

Allergen-specific Immunotherapy (AIT), through repetitive subcutaneous or sublingual administrations of allergen extracts, represents up to now the unique treatment against allergic sensitizations. However, the clinical efficacy of AIT can be largely dependent on the quality of natural allergen extracts. Moreover, the long duration and adverse side effects associated with AIT negatively impact patient adherence. Tremendous progress in the field of molecular allergology has made possible the design of safer, shorter and more effective new immunotherapeutic approaches based on purified and characterized natural or recombinant allergen derivatives and peptides. This review will summarize the characteristics of these different innovative vaccines including their effects in preclinical studies and clinical trials.

Effect of Oreodoxa oleracea Jacq. pollen protein allergen in albino mice

INTRODUCTION

Pollen trigger allergenic reactions in hypersensitive individuals due to the presence of protein in their sporoderm.

AIM

Pollen protein produced by Oreodoxa oleracea was subjected to allergenicity test in mice in order to determine its allergenic potential.

MATERIAL AND METHODS

Pollen protein was extracted using 0.02 M phosphate buffered saline and used to inoculate mice by two subcutaneous and one intranasal injections weekly for 4 weeks. Blood samples were obtained by retro-orbital bleedings, sera obtained were used in detecting immunoglobulin E (IgE) by immunoperoxidase assay. Values of immune cell and IgE elicited in mice were analysed using SPSS statistical package version 20.

RESULTS

Oreodoxa oleracea yielded 208 µg/ml pollen protein allergen. Inoculation of pollen protein in mice produced dermatophytic allergic reactions which physically presented as swelling, rashes and hair loss. Pollen protein skewed basophil production and infiltration of lymphocytes by 1-62% and 58-99% respectively in relation to controls. Histopathology analysis showed inflammation within the lung parenchyma.

CONCLUSIONS

The present study is the first study to evaluate the allergenic potential of Oreodoxa oleracea in mice. The findings revealed that Oreodoxa oleracea which is profoundly planted in pubic areas for aesthetic purposes possess allergenic effect.

Egg Allergy: Diagnosis and Immunotherapy

Hypersensitivity or an allergy to chicken egg proteins is a predominant symptomatic condition affecting 1 in 20 children in Australia; however, an effective form of therapy has not yet been found. This occurs as the immune system of the allergic individual overreacts when in contact with egg allergens (egg proteins), triggering a complex immune response. The subsequent instantaneous inflammatory immune response is characterized by the excessive production of immunoglobulin E (IgE) antibody against the allergen, T-cell mediators and inflammation. Current allergen-specific approaches to egg allergy diagnosis and treatment lack consistency and therefore pose safety concerns among anaphylactic patients. Immunotherapy has thus far been found to be the most efficient way to treat and relieve symptoms, this includes oral immunotherapy (OIT) and sublingual immunotherapy (SLIT). A major limitation in immunotherapy, however, is the difficulty in preparing effective and safe extracts from natural allergen sources. Advances in molecular techniques allow for the production of safe and standardized recombinant and hypoallergenic egg variants by targeting the IgE-binding epitopes responsible for clinical allergic symptoms. Site-directed mutagenesis can be performed to create such safe hypoallergens for their potential use in future methods of immunotherapy, providing a feasible standardized therapeutic approach to target egg allergies safely.

Preventive Allergen-Specific Vaccination Against Allergy: Mission Possible?

Vaccines for infectious diseases have improved the life of the human species in a tremendous manner. The principle of vaccination is to establish de novo adaptive immune response consisting of antibody and T cell responses against pathogens which should defend the vaccinated person against future challenge with the culprit pathogen. The situation is completely different for immunoglobulin E (IgE)-associated allergy, an immunologically-mediated hypersensitivity which is already characterized by increased IgE antibody levels and T cell responses against per se innocuous antigens (i.e., allergens). Thus, allergic patients suffer from a deviated hyper-immunity against allergens leading to inflammation upon allergen contact. Paradoxically, vaccination with allergens, termed allergen-specific immunotherapy (AIT), induces a counter immune response based on the production of high levels of allergen-specific IgG antibodies and alterations of the adaptive cellular response, which reduce allergen-induced symptoms of allergic inflammation. AIT was even shown to prevent the progression of mild to severe forms of allergy. Consequently, AIT can be considered as a form of therapeutic vaccination. In this article we describe a strategy and possible road map for the use of an AIT approach for prophylactic vaccination against allergy which is based on new molecular allergy vaccines. This road map includes the use of AIT for secondary preventive vaccination to stop the progression of clinically silent allergic sensitization toward symptomatic allergy and ultimately the prevention of allergic sensitization by maternal vaccination and/or early primary preventive vaccination of children. Prophylactic allergy vaccination with molecular allergy vaccines may allow halting the allergy epidemics affecting almost 30% of the population as it has been achieved for vaccination against infectious diseases.

Recombinant allergens for immunotherapy: state of the art

PURPOSE OF REVIEW

More than 30 years ago, the first molecular structures of allergens were elucidated and defined recombinant allergens became available. We review the state of the art regarding molecular AIT with the goal to understand why progress in this field has been slow, although there is huge potential for treatment and allergen-specific prevention.

RECENT FINDINGS

On the basis of allergen structures, several AIT strategies have been developed and were advanced into clinical evaluation. In clinical AIT trials, promising results were obtained with recombinant and synthetic allergen derivatives inducing allergen-specific IgG antibodies, which interfered with allergen recognition by IgE whereas clinical efficacy could not yet be demonstrated for approaches targeting only allergen-specific T-cell responses. Available data suggest that molecular AIT strategies have many advantages over allergen extract-based AIT.

SUMMARY

Clinical studies indicate that recombinant allergen-based AIT vaccines, which are superior to existing allergen extract-based AIT can be developed for respiratory, food and venom allergy. Allergen-specific preventive strategies based on recombinant allergen-based vaccine approaches and induction of T-cell tolerance are on the horizon and hold promise that allergy can be prevented. However, progress is limited by lack of resources needed for clinical studies, which are necessary for the development of these innovative strategies.

ELISA-Based Assay for Studying Major and Minor Group Rhinovirus-Receptor Interactions

Rhinovirus (RV) infections are a major cause of recurrent common colds and trigger severe exacerbations of chronic respiratory diseases. Major challenges for the development of vaccines for RV include the virus occurring in the form of approximately 160 different serotypes, using different receptors, and the need for preclinical models for the screening of vaccine candidates and antiviral compounds. We report the establishment and characterization of an ELISA-based assay for studying major and minor group RV-receptor interactions. This assay is based on the interaction of purified virus with plate-bound human receptor proteins, intercellular adhesion molecule 1 (ICAM-1), and low density lipoprotein receptor (LDLR). Using RV strain-specific antibodies, we demonstrate the specific binding of a panel of major and minor RV group types including RV-A and RV-B strains to ICAM-1 and LDLR, respectively. We show that the RV-receptor interaction can be blocked with receptor-specific antibodies as well as with soluble receptors and neutralizing RV-specific antibodies. The assay is more sensitive than a cell culture-based virus neutralization test. The ELISA assay will therefore be useful for the preclinical evaluation for preventive and therapeutic strategies targeting the RV-receptor interaction, such as vaccines, antibodies, and anti-viral compounds.

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.

Microbial Delivery Vehicles for Allergens and Allergen-Derived Peptides in Immunotherapy of Allergic Diseases

Allergen-specific immunotherapy represents the only available curative approach to allergic diseases. The treatment has proven effective, but it requires repetitive administrations of allergen extracts over 3-5 years and is often associated with adverse events. This implies the need for novel therapeutic strategies with reduced side effects and decreased treatment time, which would improve patients' compliance. Development of vaccines that are molecularly well defined and have improved safety profile in comparison to whole allergen extracts represents a promising approach. Molecular allergy vaccines are based on major allergen proteins or allergen-derived peptides. Often, such vaccines are associated with lower immunogenicity and stability and therefore require an appropriate delivery vehicle. In this respect, viruses, bacteria, and their protein components have been intensively studied for their adjuvant capacity. This article provides an overview of the microbial delivery vehicles that have been tested for use in allergy immunotherapy. We review in vitro and in vivo data on the immunomodulatory capacity of different microbial vehicles for allergens and allergen-derived peptides and evaluate their potential in development of allergy vaccines. We also discuss relevant aspects and challenges concerning the use of microbes and their components in immunotherapy of allergic diseases.

PreDicta chip-based high resolution diagnosis of rhinovirus-induced wheeze

Rhinovirus (RV) infections are major triggers of acute exacerbations of severe respiratory diseases such as pre-school wheeze, asthma and chronic obstructive pulmonary disease (COPD). The occurrence of numerous RV types is a major challenge for the identification of the culprit virus types and for the improvement of virus type-specific treatment strategies. Here, we develop a chip containing 130 different micro-arrayed RV proteins and peptides and demonstrate in a cohort of 120 pre-school children, most of whom had been hospitalized due to acute wheeze, that it is possible to determine the culprit RV species with a minute blood sample by serology. Importantly, we identify RV-A and RV-C species as giving rise to most severe respiratory symptoms. Thus, we have generated a chip for the serological identification of RV-induced respiratory illness which should be useful for the rational development of preventive and therapeutic strategies targeting the most important RV types.

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.

Construction of a recombinant B-cell epitope vaccine based on a Der p1-derived hypoallergen: a bioinformatics approach

AIM

House dust mite (HDM) allergens are important elicitors of IgE-mediated allergies. This study was aimed at constructing and characterizing a recombinant fusion protein, DpTTDp, which was based on carrier-bound Der p 1-derived peptides for HDM allergen immunotherapy.

METHODS

Using the Immune Epitope Database (IEDB), we identified from Der p 1, a 34-mer hypoallergenic peptide. Two copies of the hypoallergen were then fused to a partial fragment of a tetanus toxoid molecule's N-and C terminus and expressed in Escherichia coli. After purification to homogeneity, the protein was evaluated for allergenicity and its ability to induce blocking antibodies upon immunization.

RESULTS

Upon immunization of mice, DpTTDp induced high levels of protective IgG-antibodies that blocked allergic patients' IgE reactivity to HDM. In addition, DpTTDp lacked relevant IgE-reactivity, induced low T-cell proliferation and IFN-γ in peripheral blood mononuclear cells of HDM-allergic patients' sera.

CONCLUSION

The protein represents a promising HDM-allergy immunotherapy candidate vaccine.

Vaccines for the common cold

BACKGROUND

The common cold is a spontaneously remitting infection of the upper respiratory tract, characterised by a runny nose, nasal congestion, sneezing, cough, malaise, sore throat, and fever (usually < 37.8º C). The widespread morbidity caused by the common cold worldwide is related to its ubiquitousness rather than its severity. The development of vaccines for the common cold has been difficult because of antigenic variability of the common cold virus and the indistinguishable multiple other viruses and even bacteria acting as infective agents. There is uncertainty regarding the efficacy and safety of interventions for preventing the common cold in healthy people. This is an update of a Cochrane review first published in 2011 and previously updated in 2013.

OBJECTIVES

To assess the clinical effectiveness and safety of vaccines for preventing the common cold in healthy people.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (September 2016), MEDLINE (1948 to September 2016), Embase (1974 to September 2016), CINAHL (1981 to September 2016), and LILACS (1982 to September 2016). We also searched three trials registers for ongoing studies and four websites for additional trials (February 2017). We included no language or date restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of any virus vaccines compared with placebo to prevent the common cold in healthy people.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated methodological quality and extracted trial data. We resolved disagreements by discussion or by consulting a third review author.

MAIN RESULTS

We found no additional RCTs for inclusion in this update. This review includes one RCT dating from the 1960s with an overall high risk of bias. The RCT included 2307 healthy participants, all of whom were included in analyses. This trial compared the effect of an adenovirus vaccine against placebo. No statistically significant difference in common cold incidence was found: there were 13 (1.14%) events in 1139 participants in the vaccines group and 14 (1.19%) events in 1168 participants in the placebo group (risk ratio 0.95, 95% confidence interval 0.45 to 2.02; P = 0.90). No adverse events related to the live vaccine were reported. The quality of the evidence was low due to limitations in methodological quality and a wide 95% confidence interval.

AUTHORS' CONCLUSIONS

This Cochrane Review was based on one study with low-quality evidence. We found no conclusive results to support the use of vaccines for preventing the common cold in healthy people compared with placebo. We identified a need for well-designed, adequately powered RCTs to investigate vaccines for the common cold in healthy people. Any future trials on medical treatments for preventing the common cold should assess a variety of virus vaccines for this condition. Outcome measures should include common cold incidence, vaccine safety, and mortality related to the vaccine.

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.

Evidence in immunotherapy for paediatric respiratory allergy: Advances and recommendations

Allergic respiratory diseases are major health problems in paediatric population due their high level of prevalence and chronicity, and to their relevance in the costs and quality of life. One of the most important risk factors for the development of airway diseases in children and adolescents is atopy. The mainstays for the treatment of these diseases are avoiding allergens, controlling symptoms, and preventing them through sustained desensitization by allergen immunotherapy (AIT). AIT is a treatment option that consists in the administration of increasing amounts of allergens to modify the biological response to them, inducing long-term tolerance even after treatment has ended. This treatment approach has shown to decrease symptoms and improve quality of life, becoming cost effective for a large number of patients. In addition, it is considered the only treatment that can influence the natural course of the disease by targeting the cause of the allergic inflammatory response. The aim of this publication is to reflect the advances of AIT in the diagnosis and treatment of allergic respiratory diseases in children and adolescents reviewing articles published since 2000, establishing evidence categories to support the strength of the recommendations based on evidence. The first part of the article covers the prerequisite issues to understand how AIT is effective, such as the correct etiologic and clinical diagnosis of allergic respiratory diseases. Following this, the article outlines the advancements in understanding the mechanisms by which AIT achieve immune tolerance to allergens. Administration routes, treatment regimens, dose and duration, efficacy, safety, and factors associated with adherence are also reviewed. Finally, the article reviews future advances in the research of AIT.

The Use of Adjuvants for Enhancing Allergen Immunotherapy Efficacy

One key approach to increase the efficacy and the safety of immunotherapy is the use of adjuvants. However, many of the adjuvants currently in use can cause adverse events, raising concerns regarding their clinical use, and are geared toward productive immune responses but not necessarily tolerogenic responses. Thus, novel adjuvants for immunotherapy are needed and are being developed. Essential is their potential to boost appropriate tolerogenic adaptive immune responses to allergens while limiting side effects. This review provides an overview of adjuvants currently in clinical use or under development and discusses their therapeutic effect in enhancing allergen-induced tolerance.

Vaccine development for allergen-specific immunotherapy based on recombinant allergens and synthetic allergen peptides: Lessons from the past and novel mechanisms of action for the future

In the past, the development of more effective, safe, convenient, broadly applicable, and easy to manufacture vaccines for allergen-specific immunotherapy (AIT) has been limited by the poor quality of natural allergen extracts. Progress made in the field of molecular allergen characterization has now made it possible to produce defined vaccines for AIT and eventually for preventive allergy vaccination based on recombinant DNA technology and synthetic peptide chemistry. Here we review the characteristics of recombinant and synthetic allergy vaccines that have reached clinical evaluation and discuss how molecular vaccine approaches can make AIT more safe and effective and thus more convenient. Furthermore, we discuss how new technologies can facilitate the reproducible manufacturing of vaccines of pharmaceutical grade for inhalant, food, and venom allergens. Allergy vaccines in clinical trials based on recombinant allergens, recombinant allergen derivatives, and synthetic peptides allow us to target selectively different immune mechanisms, and certain of those show features that might make them applicable not only for therapeutic but also for prophylactic vaccination.

Allergen extracts for immunotherapy: to mix or not to mix?

Allergen immunotherapy (AIT) is established as a curative treatment for allergic rhinitis, asthma, as well as insect venom allergy. AIT is based on the administration of natural allergen extracts via the subcutaneous or sublingual routes to reorient the immune system towards tolerogenic mechanisms. In this regard, since many patients are poly-allergic, mixtures of allergen extracts are often used with a potential risk to cause allergen degradation, thereby affecting treatment efficacy. Herein, we discuss the advantages and drawbacks of mixing homologous (i.e., related) or heterogeneous (i.e., unrelated) allergen extracts. We provide evidence for incompatibilities between mixes of grass pollen and house dust mite extracts containing bodies and feces, and summarize critical points to consider when mixing allergen extracts for AIT.

Contributing factors to the development of childhood asthma: working toward risk minimization

Asthma is the most common chronic disease in childhood, and considerable research has been undertaken to find ways to prevent its development and reduce its prevalence. For such interventions to be successful, risk factors for asthma emergence should be identified and clearly defined. Data are robust for some of them, including atopy, viral infections and exposure to airborne irritants, whereas it is less conclusive for others, such as aeroallergen exposure and bacterial infections. Several interventions for asthma prevention, including avoidance and pharmacotherapy, have been attempted. However, most of them have furnished equivocal results. Various issues hinder the establishment of risk factors for asthma development and reduce the effectiveness of interventions, including the complexity of the disease and the fluidity of the developing systems in childhood. In this review, we revisit the evidence on pediatric asthma risk factors and prevention and discuss issues that perplex this field.

Mold allergens in respiratory allergy: from structure to therapy

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

Development and characterization of a recombinant, hypoallergenic, peptide-based vaccine for grass pollen allergy

Background

Grass pollen is one of the most important sources of respiratory allergies worldwide.

Objective

This study describes the development of a grass pollen allergy vaccine based on recombinant hypoallergenic derivatives of the major timothy grass pollen allergens Phl p 1, Phl p 2, Phl p 5, and Phl p 6 by using a peptide-carrier approach.

Methods

Fusion proteins consisting of nonallergenic peptides from the 4 major timothy grass pollen allergens and the PreS protein from hepatitis B virus as a carrier were expressed in Escherichia coli and purified by means of chromatography. Recombinant PreS fusion proteins were tested for allergenic activity and T-cell activation by means of IgE serology, basophil activation testing, T-cell proliferation assays, and xMAP Luminex technology in patients with grass pollen allergy. Rabbits were immunized with PreS fusion proteins to characterize their immunogenicity.

Results

Ten hypoallergenic PreS fusion proteins were constructed, expressed, and purified. According to immunogenicity and induction of allergen-specific blocking IgG antibodies, 4 hypoallergenic fusion proteins (BM321, BM322, BM325, and BM326) representing Phl p 1, Phl p 2, Phl p 5, and Phl p 6 were included as components in the vaccine termed BM32. BM321, BM322, BM325, and BM326 showed almost completely abolished allergenic activity and induced significantly reduced T-cell proliferation and release of proinflammatory cytokines in patients' PBMCs compared with grass pollen allergens. On immunization, they induced allergen-specific IgG antibodies, which inhibited patients' IgE binding to all 4 major allergens of grass pollen, as well as allergen-induced basophil activation.

Conclusion

A recombinant hypoallergenic grass pollen allergy vaccine (BM32) consisting of 4 recombinant PreS-fused grass pollen allergen peptides was developed for safe immunotherapy of grass pollen allergy.

Epidemiology, etiology, x-ray features, importance of co-infections and clinical features of viral pneumonia in developing countries

Pneumonia is still the number one killer of young children globally, accounting for 18% of mortality in children under 5 years of age. An estimated 120 million new cases of pneumonia occur globally each year. In developing countries, management and prevention efforts against pneumonia have traditionally focused on bacterial pathogens. More recently however, viral pathogens have gained attention as a result of improved diagnostic methods, such as polymerase chain reaction, outbreaks of severe disease caused by emerging pathogens, discovery of new respiratory viruses as well as the decrease in bacterial pneumonia as a consequence of the introduction of highly effective conjugate vaccines. Although the epidemiology, etiology and clinical characterization of viral infections are being studied extensively in the developed world, little data are available from low- and middle-income countries. In this paper, we review the epidemiology, etiology, clinical and radiological features of viral pneumonia in developing countries.

Adeno-associated virus-like particles as new carriers for B-cell vaccines: testing immunogenicity and safety in BALB/c mice

Adeno-associated viruses (AAVs) are established vectors for gene therapy of different human diseases. AAVs are assembled of 60 capsomers, which can be genetically modified, allowing high-density display of short peptide sequences at their surface. The aim of our study was to evaluate the immunogenicity and safety of an adeno-associated virus-like particle (AAVLP)-displayed B-cell peptide epitope taking ovalbumin (OVA) as a model antigen or allergen from egg, respectively. An OVA-derived B-cell epitope was expressed as fusion protein with the AAV-2 capsid protein of VP3 (AAVLP-OVA) and for control, with the nonrelated peptide TP18 (AAVLP-TP18). Cellular internalization studies revealed an impaired uptake of AAVLP-OVA by mouse BMDC, macrophages, and human HeLa cells. Nevertheless, BALB/c mice immunized subcutaneously with AAVLP-OVA formed similarly high titers of OVA-specific IgG1 compared to mice immunized with the native OVA. The extent of the immune response was independent whether aluminum hydroxide or water in oil emulsion was used as adjuvant. Furthermore, in mice immunized with native OVA, high OVA-specific IgE levels were observed, which permitted OVA-specific mast-cell degranulation in a β-hexosaminidase release assay, whereas immunizations with AAVLP-OVA rendered background IgE levels only. Accordingly, OVA-immunized mice, but not AAVLP-OVA immunized mice, displayed an anaphylactic reaction with a significant drop of body temperature upon intravenous OVA challenge. From this mouse model, we conclude that AAVLPs that display B-cell epitope peptides on their surface are suitable vaccine candidates, especially in the field of allergy.

Prophylactic and therapeutic vaccination with carrier-bound Bet v 1 peptides lacking allergen-specific T cell epitopes reduces Bet v 1-specific T cell responses via blocking antibodies in a murine model for birch pollen allergy

Background

Vaccines consisting of allergen-derived peptides lacking IgE reactivity and allergen-specific T cell epitopes bound to allergen-unrelated carrier molecules have been suggested as candidates for allergen-specific immunotherapy.

Objective

To study whether prophylactic and therapeutic vaccination with carrier-bound peptides from the major birch pollen allergen Bet v 1 lacking allergen-specific T cell epitopes has influence on Bet v 1-specific T cell responses.

Methods

Three Bet v 1-derived peptides, devoid of Bet v 1-specific T cell epitopes, were coupled to KLH and adsorbed to aluminium hydroxide to obtain a Bet v 1-specific allergy vaccine. Groups of BALB/c mice were immunized with the peptide vaccine before or after sensitization to Bet v 1. Bet v 1- and peptide-specific antibody responses were analysed by ELISA. T cell and cytokine responses to Bet v 1, KLH, and the peptides were studied in proliferation assays. The effects of peptide-specific and allergen-specific antibodies on T cell responses and allergic lung inflammation were studied using specific antibodies.

Results

Prophylactic and therapeutic vaccination with carrier-bound Bet v 1 peptides induced a Bet v 1-specific IgG antibody response without priming/boosting of Bet v 1-specific T cells. Prophylactic and therapeutic vaccination of mice with the peptide vaccine induced Bet v 1-specific antibodies which suppressed Bet v 1-specific T cell responses and allergic lung inflammation.

Conclusion and Clinical Relevance

Vaccination with carrier-bound allergen-derived peptides lacking allergen-specific T cell epitopes induces allergen-specific IgG antibodies which suppress allergen-specific T cell responses and allergic lung inflammation.

Conference Scene: novelties in immunotherapy

The only method aiming to permanently cure allergic disorders is allergen immunotherapy. Over the last 20 years there has been great progress in understanding the mechanisms that govern allergen immunotherapy in order to meet three basic prerequisites: safety, effectiveness and compliance. In the present summary report from the European Academy of Allergology and Clinical Immunology-World Allergy Organization Congress held last June in Milan, we review key points concerning the main axes as diagnosis, novel modalities, routes and protocols, as well as two important immunotherapy fields: food and insect venom allergy.

Multiple grass mixes as opposed to single grasses for allergen immunotherapy in allergic rhinitis

Grass pollen allergy affects approximately 40% of allergic patients. Subcutaneous allergen immunotherapy (SCIT) is the only allergen-specific and disease-modifying treatment available. Currently available therapeutic vaccines for the treatment of grass pollen allergy are based on natural grass pollen extracts which are either made from pollen of one cross-reactive grass species or from several related grass species. Clinical studies have shown that SCIT performed with timothy grass pollen extract is effective for the treatment of grass pollen allergy. Moreover, it has been demonstrated that recombinant timothy grass pollen allergens contain the majority of relevant epitopes and can be used for SCIT in clinical trials. However, recent in vitro studies have suggested that mixes consisting of allergen extracts from several related grass species may have advantages for SCIT over single allergen extracts. Here, we review current knowledge regarding the disease-relevant allergens in grass pollen allergy, available clinical studies comparing SCIT with allergen extracts from timothy grass or from mixes of several related grass species of the Pooideae subfamily, in vitro cross-reactivity studies performed with natural allergen extracts and recombinant allergens and SCIT studies performed with recombinant timothy grass pollen allergens. In vitro and clinical studies performed with natural allergen extracts reveal no relevant advantages of using multiple grass mixes as opposed to single grass pollen extracts. Several studies analysing the molecular composition of natural allergen extracts and the molecular profile of patients' immune responses after SCIT with allergen extracts indicate that the major limitation for the production of a high quality grass pollen vaccine resides in intrinsic features of natural allergen extracts which can only be overcome with recombinant allergen-based technologies.

Management of severe asthma in childhood--state of the art and novel perspectives

The majority of children with asthma have mild or moderate disease and can obtain adequate control of symptoms through avoidance of triggering factors and/or with the help of medications. There is still a group of children with severe asthma in whom symptom control is poor depending either on identifiable aggravating factors or on true therapy resistance. These children have a poor quality of life and are limited by the severity of their disease. There is a need for a staged approach to the assessment and treatment of this small but vulnerable and resource-consuming group. The current review will provide an overview of a possible standardized approach to characterize this heterogeneous group of severely sick children including some newly developed ways of assessing asthma severity and potentialities of new asthma therapies. Furthermore, the umbrella term 'problematic severe asthma' is described. The term encompasses children whose severe asthma is due to identifiable exacerbating factors, as well as children who are resistant to any conventional therapeutic approach. Characteristics of these two groups of children are described, as are possible biomarkers and current and emerging diagnostic tools for allergy evaluation. Some recent advances and future possibilities for treatment of severe asthma are also presented in this review.

Recombinant allergen-based provocation testing

Over the last 25 years, recombinant allergens from all important allergen sources have been cloned and are now available as recombinant proteins. These molecules can be produced in practically unlimited amounts without biological or batch-to-batch variability. It has been shown in provocation tests that recombinant allergens have similar clinical effects as their natural counterparts. With the help of these tools it is possible to reveal the precise reactivity profiles of patients and to uncover and differentiate cross-reactivity from genuine sensitization to an allergen source. Although it has been shown some time ago that it would be possible to replace crude allergen extracts with recombinant allergens for skin prick testing, and even though the use of allergen components can improve routine diagnosis, these tools are still not available for clinical routine applications. The use of provocation tests is a crucial step in the development of new, hypoallergenic vaccines for therapy of allergic disease. Here we describe important provocation methods (skin prick test, intradermal test, atopy patch test, nasal provocation, colonoscopic provocation test) and give an overview of the clinical provocation studies which have been performed with recombinant allergens so far.

Dissection of the IgE and T-cell recognition of the major group 5 grass pollen allergen Phl p 5

BACKGROUND

The major timothy grass pollen allergen Phl p 5 belongs to the most potent allergens involved in hay fever and asthma.

OBJECTIVE

This study characterized immune-dominant IgE- and T-cell-recognition sites of Phl p 5.

METHODS

Seven peptides, P1 to P7 with a length of 31 to 38 amino acids that spanned the Phl p 5 sequence, were synthesized, characterized by circular dichroism spectroscopy, and tested for IgE reactivity, basophil activation, and T-cell reactivity. Carrier-bound peptides were studied for their ability to induce IgG antibodies in rabbits which recognize Phl p 5 or cross-reactive allergens from different grass species. Peptide-specific antibodies were tested for the capability to inhibit IgE reactivity to Phl p 5 and allergen-induced basophil activation of patients with allergy.

RESULTS

The peptides exhibited no secondary structure and showed no IgE reactivity or relevant allergenic activity, indicating that Phl p 5 IgE epitopes are conformational. Except for P3, peptide-specific IgG antibodies blocked IgE binding to Phl p 5 of patients with allergy and cross-reacted with temperate grasses. IgE inhibition experiments and molecular modeling identified several clustered conformational IgE epitopes on the N- as well as C-terminal domain of Phl p 5. P4, which stimulated the strongest T-cell and cytokine responses in patients, was not part of the major IgE-reactive regions.

CONCLUSION

Our study shows an interesting dissociation of the major IgE- and T-cell-reactive domains in Phl p 5 which provides a basis for the development of novel forms of immunotherapy that selectively target IgE or T-cell responses.

Allergen Peptides, Recombinant Allergens and Hypoallergens for Allergen-Specific Immunotherapy

Allergic diseases are among the most common health issues worldwide. Specific immunotherapy has remained the only disease-modifying treatment, but it is not effective in all patients and may cause side effects. Over the last 25 years, allergen molecules from most prevalent allergen sources have been isolated and produced as recombinant proteins. Not only are these molecules useful in improved allergy diagnosis, but they also have the potential to revolutionize the treatment of allergic disease by means of immunotherapy. Panels of unmodified recombinant allergens have already been shown to effectively replace natural allergen extracts in therapy. Through genetic engineering, several molecules have been designed with modified immunological properties. Hypoallergens have been produced that have reduced IgE binding capacity but retained T cell reactivity and T cell peptides which stimulate allergen-specific T cells, and these have already been investigated in clinical trials. New vaccines have been recently created with both reduced IgE and T cell reactivity but retained ability to induce protective allergen-specific IgG antibodies. The latter approach works by fusing per se non-IgE reactive peptides derived from IgE binding sites of the allergens to a virus protein, which acts as a carrier and provides the T-cell help necessary for immune stimulation and protective antibody production. In this review, we will highlight the different novel approaches for immunotherapy and will report on prior and ongoing clinical studies.

Recombinant allergen immunotherapy: clinical evidence of efficacy--a review

Recombinant allergens for immunotherapy aim to overcome the problems of natural extracts as they can be produced in unlimited amounts with exact physiochemical and immunological properties. These can be modified to have more favourable characteristics including reduced IgE reactivity or enhanced immunogenicity. Different types of recombinant allergens have been evaluated in clinical phase II and III trials whilst others are currently under development. In this review, we identified double-blind, placebo-controlled randomised clinical trials assessing the efficacy and safety of various recombinant allergen preparations. The majority of studies have up to now focused on cat, grass, birch, ragweed and bee venom allergens. Some studies have shown some of these preparations to be effective and well tolerated. However, there are still outstanding issues regarding optimum doses, minimising side effects and long-term effects.

Mammalian-derived respiratory allergens - implications for diagnosis and therapy of individuals allergic to furry animals

Furry animals cause respiratory allergies in a significant proportion of the population. A majority of all mammalian allergens are spread as airborne particles, and several have been detected in environments where furry animals are not normally kept. The repertoire of allergens from each source belongs to a restricted number of allergen families. Classification of allergen families is particularly important for the characterization of allergenicity and cross-reactivity of allergens. In fact, major mammalian allergens are taken from only three protein families, i.e. the secretoglobin, lipocalin and kallikrein families. In particular, the lipocalin superfamily harbours major allergens in all important mammalian allergen sources, and cross-reactivity between lipocalin allergens may explain cross-species sensitization between mammals. The identification of single allergen components is of importance to improve diagnosis and therapy of allergic patients using component-resolved diagnostics and allergen-specific immunotherapy (ASIT) respectively. Major disadvantages with crude allergen extracts for these applications emphasize the benefits of careful characterization of individual allergens. Furthermore, detailed knowledge of the characteristics of an allergen is crucial to formulate attenuated allergy vaccines, e.g. hypoallergens. The diverse repertoires of individual allergens from different mammalian species influence the diagnostic potential and clinical efficacy of ASIT to furry animals. As such, detailed knowledge of individual allergens is essential for adequate clinical evaluation. This review compiles current knowledge of the allergen families of mammalian species, and discusses how this information may be used for improved diagnosis and therapy of individuals allergic to mammals.

Vaccines for the common cold

BACKGROUND

The common cold is a spontaneously remitting infection of the upper respiratory tract, characterised by a runny nose, nasal congestion, sneezing, cough, malaise, sore throat and fever (usually < 37.8˚C). The widespread morbidity it causes worldwide is related to its ubiquitousness rather than its severity. The development of vaccines for the common cold has been difficult because of antigenic variability of the common cold virus and the indistinguishable multiple other viruses and even bacteria acting as infective agents. There is uncertainty regarding the efficacy and safety of interventions for preventing the common cold in healthy people.

OBJECTIVES

To assess the clinical effectiveness and safety of vaccines for preventing the common cold in healthy people.

SEARCH METHODS

We searched CENTRAL (2012, Issue 12), MEDLINE (1948 to January week 1, 2013), EMBASE (1974 to January 2013), CINAHL (1981 to January 2013) and LILACS (1982 to January 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of any virus vaccines to prevent the common cold in healthy people.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated methodological quality and extracted trial data. Disagreements were resolved by discussion or by consulting a third review author.

MAIN RESULTS

This review included one RCT with 2307 healthy participants; all of them were analysed. This trial compared the effect of an adenovirus vaccine against a placebo. No statistically significant difference in common cold incidence was found: there were 13 events in 1139 participants in the vaccines group and 14 events in 1168 participants in the placebo group; risk ratio (RR) 0.95, 95% confidence interval (CI) 0.45 to 2.02, P = 0.90). No adverse events related to the live vaccine were reported.

AUTHORS' CONCLUSIONS

This Cochrane review has found a lack of evidence on the effects of vaccines for the common cold in healthy people. Only one RCT was found and this did not show differences between comparison groups; it also had a high risk of bias. There are no conclusive data to support the use of vaccines for preventing the common cold in healthy people. We identified the need for well-designed, adequately powered RCTs to investigate vaccines for the common cold in healthy people. Unless RCTs provide evidence of a treatment effect and the trade-off between potential benefits and harms is established, policy-makers, clinicians and academics should not recommend the use of vaccines for preventing the common cold in healthy people. Any future trials on medical treatments for preventing the common cold should assess a variety of virus vaccines for this condition. Outcome measures should include common cold incidence, vaccine safety and mortality related to the vaccine.

New directions in immunotherapy

Allergen immunotherapy (AIT) is effective in reducing the clinical symptoms associated with allergic rhinitis, asthma and venom-induced anaphylaxis. Subcutaneous (SCIT) and sublingual immunotherapy (SLIT) with unmodified allergen extracts are the most widely prescribed AIT regimens. The efficacy of these 2 routes appears comparable, but the safety profile with SLIT is more favorable allowing for home administration and requiring less patient time. However, both require that the treatment is taken regularly over several years, e.g., monthly in a supervised medical setting with SCIT and daily at home with SLIT. Despite the difference in treatment settings, poor adherence has been reported with both routes. Emerging evidence suggests that AIT may be effective in other allergic conditions such as atopic dermatitis, venom sting-induced large local reactions, and food allergy. Research with oral immunotherapy (OIT) for food allergies suggest that many patients can be desensitized during treatment, but questions remain about whether this can produce long term tolerance. Further studies are needed to identify appropriate patients and treatment regimens with these conditions. Efforts to develop safer and more effective AIT for inhalant allergies have led to investigations with modified allergens and alternate routes. Intralymphatic (ILIT) has been shown to produce long-lasting clinical benefits after three injections comparable to a 3-year course of SCIT. Epicutaneous (EPIT) has demonstrated promising results for food and inhalant allergies. Vaccine modifications, such as T cell epitopes or the use of viral-like particles as an adjuvant, have been shown to provide sustained clinical benefits after a relatively short course of treatment compared to the currently available AIT treatments, SLIT and SCIT. These newer approaches may increase the utilization and adherence to AIT because the multi-year treatment requirement of currently available AIT is a likely deterrent for initiating and adhering to treatment.

Safety of engineered allergen-specific immunotherapy vaccines

PURPOSE OF REVIEW

The purpose of the review is to summarize and comment on recent developments regarding the safety of engineered immunotherapy vaccines.

RECENT FINDINGS

In the last 2 years, several studies were published in which allergy vaccines were developed on the basis of chemical modification of natural allergen extracts, the engineering of allergen molecules by recombinant DNA technology and synthetic peptide chemistry, allergen genes, new application routes and conjugation with immune modulatory molecules. Several studies exemplified the general applicability of hypoallergenic vaccines on the basis of recombinant fusion proteins consisting of nonallergenic allergen-derived peptides fused to allergen-unrelated carrier molecules. These vaccines are engineered to reduce both, immunoglobulin E (IgE) as well as allergen-specific T cell epitopes in the vaccines, and thus should provoke less IgE and T-cell-mediated side-effects. They are made to induce allergen-specific IgG antibodies against the IgE-binding sites of allergens with the T-cell help of the carrier molecule.

SUMMARY

Several interesting examples of allergy vaccines with potentially increased safety profiles have been published. The concept of fusion proteins consisting of allergen-derived hypoallergenic peptides fused to allergen-unrelated proteins that seems to be broadly applicable for a variety of allergens appears to be of particular interest because it promises not only to reduce side-effects but also to increase efficacy and convenience of allergy vaccines.

Carrier-bound Alt a 1 peptides without allergenic activity for vaccination against Alternaria alternata allergy

BACKGROUND

The mould Alternaria alternata is a major elicitor of allergic asthma. Diagnosis and specific immunotherapy (SIT) of Alternaria allergy are often limited by the insufficient quality of natural mould extracts.

OBJECTIVE

To investigate whether recombinant Alt a 1 can be used for reliable diagnosis of Alternaria alternata allergy and to develop a safe, non-allergenic vaccine for SIT of Alternaria allergy.

METHODS

The qualitative sensitization profile of 80 Alternaria-allergic patients from Austria and Italy was investigated using an allergen micro-array and the amount of Alternaria-specific IgE directed to rAlt a 1 was quantified by ImmunoCAP measurements. Peptides spanning regions of predicted high surface accessibility of Alt a 1 were synthesized and tested for IgE reactivity and allergenic activity, using sera and basophils from allergic patients. Carrier-bound peptides were studied for their ability to induce IgG antibodies in rabbits which recognize Alt a 1 and inhibit allergic patients' IgE reactivity to Alt a 1.

RESULTS

rAlt a 1 allowed diagnosis of Alternaria allergy in all tested patients, bound the vast majority (i.e. >95%) of Alternaria-specific IgE and elicited basophil activation already at a concentration of 0.1 ng/mL. Four non-allergenic peptides were synthesized which, after coupling to the carrier protein keyhole limpet hemocyanin, induced Alt a 1-specific IgG and inhibited allergic patients' IgE binding to Alt a 1.

CONCLUSIONS AND CLINICAL RELEVANCE

rAlt a 1 is a highly allergenic molecule allowing sensitive diagnosis of Alternaria allergy. Carrier-bound non-allergenic Alt a 1 peptides are candidates for safe SIT of Alternaria allergy.

Strategies to query and display allergy-derived epitope data from the immune epitope database

The recognition of specific epitopes on allergens by antibodies and T cells is a key element in allergic processes. Analysis of epitope data may be of interest for basic immunopathology or for potential application in diagnostics or immunotherapy. The Immune Epitope Database (IEDB) is a freely available repository of epitope data from infectious disease agents, as well as epitopes defined for allergy, autoimmunity, and transplantation. The IEDB curates the experiments associated with each epitope and thus provides a variety of different ways to search the data. This review aims to demonstrate the utility of the IEDB and its query strategies, including searching by epitope structure (peptidic/nonpeptidic), by assay methodology, by host, by the allergen itself, or by the organism from which the allergen was derived. Links to tools for visualization of 3-D structures, epitope prediction, and analyses of B and T cell reactivity by host response frequency score are also highlighted.

Adjuvants for allergy vaccines

Allergen-specific immunotherapy is currently performed via either the subcutaneous or sublingual routes as a treatment for type I (IgE dependent) allergies. Aluminum hydroxide or calcium phosphate are broadly used as adjuvants for subcutaneous allergy vaccines, whereas commercial sublingual vaccines rely upon high doses of aqueous allergen extracts in the absence of any immunopotentiator. Adjuvants to be included in the future in products for allergen specific immunotherapy should ideally enhance Th1 and CD4+ regulatory T cell responses. Imunomodulators impacting dendritic or T cell functions to induce IL10, IL12 and IFNγ production are being investigated in preclinical allergy models. Such candidate adjuvants encompass synthetic or biological immunopotentiators such as glucocorticoids, 1,25-dihydroxy vitamin D3, selected probiotic strains (e.g., Lactobacillus and Bifidobacterium species) as well as TLR2 (Pam3CSK4), TLR4 (monophosphoryl lipid A, synthetic lipid A analogs) or TLR9 (CpGs) ligands. Furthermore, the use of vector systems such as mucoadhesive particules, virus-like particles or liposomes are being considered to enhance allergen uptake by tolerogenic antigen presenting cells present in mucosal tissues.

Allergen-specific immunotherapy: from therapeutic vaccines to prophylactic approaches

Immunoglobulin E-mediated allergies affect more than 25% of the population. Allergen exposure induces a variety of symptoms in allergic patients, which include rhinitis, conjunctivitis, asthma, dermatitis, food allergy and life-threatening systemic anaphylaxis. At present, allergen-specific immunotherapy (SIT), which is based on the administration of the disease-causing allergens, is the only disease-modifying treatment for allergy. Current therapeutic allergy vaccines are still prepared from relatively poorly defined allergen extracts. However, with the availability of the structures of the most common allergen molecules, it has become possible to produce well-defined recombinant and synthetic allergy vaccines that allow specific targeting of the mechanisms of allergic disease. Here we provide a summary of the development and mechanisms of SIT, and then review new forms of therapeutic vaccines that are based on recombinant and synthetic molecules. Finally, we discuss possible allergen-specific strategies for prevention of allergic disease.