Katarzyna Niespodziana

A Combination Vaccine for Allergy and Rhinovirus Infections Based on Rhinovirus-Derived Surface Protein VP1 and a Nonallergenic Peptide of the Major Timothy Grass Pollen Allergen Phl p 1

Allergens and rhinovirus infections are among the most common elicitors of respiratory diseases. We report the construction of a recombinant combination vaccine for allergy and rhinovirus infections based on rhinovirus-derived VP1, the surface protein which is critically involved in infection of respiratory cells, and a nonallergenic peptide of the major grass pollen allergen Phl p 1. Recombinant hybrid molecules consisting of VP1 and a Phl p 1-derived peptide of 31 aa were expressed in Escherichia coli. The hybrid molecules did not react with IgE Abs from grass pollen allergic patients and lacked allergenic activity when exposed to basophils from allergic patients. Upon immunization of mice and rabbits, the hybrids did not sensitize against Phl p 1 but induced protective IgG Abs that cross-reacted with group 1 allergens from different grass species and blocked allergic patients’ IgE reactivity to Phl p 1 as well as Phl p 1-induced basophil degranulation. Moreover, hybrid-induced IgG Abs inhibited rhinovirus infection of cultured human epithelial cells. The principle of fusing nonallergenic allergen-derived peptides onto viral carrier proteins may be used for the engineering of safe allergy vaccines which also protect against viral infections.

Recombinant allergens: What does the future hold?

This year we are celebrating not only the centenary of allergen-specific immunotherapy but also the 10-year anniversary of the first administration of recombinant allergen-based vaccines to allergic patients. By using recombinant DNA technology, defined and safe allergy vaccines can be produced that allow us to overcome many, if not all, of the problems associated with the use of natural allergen extracts, such as insufficient quality, allergenic activity, and poor immunogenicity. Here we provide an update of clinical studies with recombinant allergen-based vaccines, showing that some of these vaccines have undergone successful clinical evaluation up to phase III studies. Furthermore, we introduce a strategy for allergen-specific immunotherapy based on recombinant fusion proteins consisting of viral carrier proteins and allergen-derived peptides without allergenic activity, which holds the promise of being free of side effects and eventually being useful for prophylactic vaccination.

Antibodies induced with recombinant VP1 from human rhinovirus exhibit cross-neutralisation

Human rhinoviruses (HRVs) are the major cause of the common cold and account for 30–50% of all acute respiratory illnesses. Although HRV infections are usually harmless and invade only the upper respiratory tract, several studies demonstrate that HRV is involved in the exacerbation of asthma. VP1 is one of the surface-exposed proteins of the viral capsid that is important for the binding of rhinoviruses to the corresponding receptors on human cells. Here we investigated its potential usefulness for vaccination against the common cold. We expressed VP1 proteins from two distantly related HRV strains, HRV89 and HRV14, in Escherichia coli. Mice and rabbits were immunised with the purified recombinant proteins. The induced antibodies reacted with natural VP1 and with whole virus particles as shown by immunoblotting and immunogold electron microscopy. They exhibited strong cross-neutralising activity for different HRV strains. Therefore, recombinant VP1 may be considered a candidate HRV vaccine to prevent HRV-induced asthma exacerbations.

Rhinovirus infections and immunisation induce cross-serotype reactive antibodies to VP1

Rhinoviruses (RVs) are ubiquitous human respiratory viruses, the major cause of common colds, acute exacerbations of asthma and other respiratory diseases. The development of antibodies to RV following primary infection is poorly understood and there is currently no RV vaccine available. We therefore used mouse models of intranasal RV infection and immunisation to determine the induction, magnitude and specificity of antibody responses. Strong cross-serotype RV-specific IgG responses in serum and bronchoalveolar lavage were induced towards the RV capsid protein VP1. IgA responses were weaker, requiring two infections to generate detectable RV-specific binding. Similarly two or more RV infections were necessary to induce neutralising antibodies. Immunisation strategies boosted homotypic as well as inducing cross-serotype neutralising IgG responses. We conclude that VP1 based antigens combined with adjuvants may permit successful antibody-mediated vaccine design and development.

Misdirected antibody responses against an N-terminal epitope on human rhinovirus VP1 as explanation for recurrent RV infections

Rhinoviruses (RVs) are the primary cause of upper respiratory tract infections, generally known as the common cold. Moreover, RV infections can trigger severe exacerbations of asthma and chronic obstructive pulmonary disease (COPD). We expressed the 4 major RV capsid proteins, VP1‐VP4, in Escherichia coli and used these proteins as well as recombinant and synthetic VP1 fragments to study and map antibody responses in RV‐infected humans. VP1, which on infection binds to ICAM 1, was identified as a major target for the memory immune response, residing in the IgG1 subclass and IgA class. Interestingly, this response was mainly directed against an N‐terminal 20mer peptide in VP1, P1a, which becomes exposed on intact RV only when it docks to its receptor ICAM 1. Molecular modeling using the 3‐dimensional RV capsid structures revealed that P1a was localized inside the capsid and outside the areas involved in receptor binding or RV neutralization. Our results suggest misdirection of antibody responses against a nonprotective epitope as a mechanism how RV escapes immunity and causes recurrent infections. Based on these findings, it may be possible to design vaccines against RV infections and RV‐induced respiratory diseases.—Niespodziana, K., Napora, K., Cabauatan, C., Focke‐Tejkl, M., Keller, W., Niederberger, V., Tsolia, M., Christodoulou, I., Papadopoulos, N. G., Valenta, R. Misdirected antibody responses against an N‐terminal epitope on human RV VP1 as explanation for recurrent RV infections. FASEB J. 26, 1001‐1008 (2012). www.fasebj.org

Allergen-specific immunotherapy: towards combination vaccines for allergic and infectious diseases.

IgE-mediated allergies affect more than 25% of the population. Allergen-specific immunotherapy (SIT) is an antigen-specific and disease-modifying form of treatment. It is based on the therapeutic administration of the disease-causing allergens to allergic patients. However, the fact that only allergen extracts of insufficient quality are currently available and the possible occurrence of side effects during treatment limit the broad use of SIT and prophylactic vaccination is has not yet been performed. In the last 20 years the DNA sequences of the most common allergens have been isolated and the corresponding allergens have been produced as recombinant allergens. Based on the progress made in the field of allergen characterization it is possible to improve the quality and safety of allergy vaccines and to develop new, more effective strategies for a broad application of SIT and even for prophylactic treatment. Here we discuss the development of combination vaccines for allergy and infectious diseases. This approach is based on the selection of allergen-derived peptides with reduced IgE- and T cell reactivity in order to minimize IgE- and T cell-mediated side effects as well as the potential of the vaccine to induce allergic sensitization. These peptides are fused by recombinant technology onto a viral carrier protein to obtain a combination vaccine which induces protective immunity against allergy and viral infections. The application of such combination vaccines for therapy and prophylaxis of allergy and infectious diseases is discussed.

Liposomal Leakage Induced by Virus-Derived Peptides, Viral Proteins, and Entire Virions: Rapid Analysis by Chip Electrophoresis

Permeabilization of model lipid membranes by virus-derived peptides, viral proteins, and entire virions of human rhinovirus was assessed by quantifying the release of a fluorescent dye from liposomes via a novel chip electrophoretic assay. Liposomal leakage readily occurred upon incubation with the pH-sensitive synthetic fusogenic peptide GALA and, less efficiently, with a 24mer peptide (P1-N) derived from the N-terminus of the capsid protein VP1 of human rhinovirus 2 (HRV2) at acidic pH. Negative stain transmission electron microscopy showed that liposomes incubated with the rhinovirus-derived peptide remained largely intact. At similar concentrations, the GALA peptide caused gross morphological changes of the liposomes. On a molar basis, the leakage-inducing efficiency of the P1 peptide was by about 2 orders of magnitude inferior to that of recombinant VP1 (from HRV89) and entire HRV2. This underscores the role in membrane destabilization of VP1 domains remote from the N-terminus and the arrangement of the peptide in the context of the icosahedral virion. Our method is rapid, requires tiny amounts of sample, and allows for the parallel determination of released and retained liposomal cargo.

Infection with Rhinovirus Facilitates Allergen Penetration Across a Respiratory Epithelial Cell Layer

Background: Rhinovirus infections are a major risk factor for asthma exacerbations. We sought to investigate in an in vitro system whether infection with human rhinovirus reduces the integrity and barrier function of a respiratory epithelial cell layer and thus may influence allergen penetration. Methods: We cultured the human bronchial epithelial cell line 16HBE14o- in a transwell culture system as a surrogate of respiratory epithelium. The cell monolayer was infected with human rhinovirus 14 at 2 different doses. The extent and effects of transepithelial allergen penetration were assessed using transepithelial resistance measurements and a panel of 125I-labeled purified recombinant respiratory allergens (rBet v 1, rBet v 2, and rPhl p 5). Results: Infection of respiratory cell monolayers with human rhinovirus decreased transepithelial resistance and induced a pronounced increase in allergen penetration. Conclusions: Our results indicate that infection with rhinovirus damages the respiratory epithelial barrier and allows allergens to penetrate more efficiently into the subepithelial tissues where they may cause increased allergic inflammation.

Rhinovirus-induced VP1-specific Antibodies are Group-specific and Associated With Severity of Respiratory Symptoms

Background Rhinoviruses (RVs) are a major cause of common colds and induce exacerbations of asthma and chronic inflammatory lung diseases. Methods We expressed and purified recombinant RV coat proteins VP1-4, non-structural proteins as well as N-terminal fragments of VP1 from four RV strains (RV14, 16, 89, C) covering the three known RV groups (RV-A, RV-B and RV-C) and measured specific IgG-subclass-, IgA- and IgM-responses by ELISA in subjects with different severities of asthma or without asthma before and after experimental infection with RV16. Findings Before infection subjects showed IgG1 > IgA > IgM > IgG3 cross-reactivity with N-terminal fragments from the representative VP1 proteins of the three RV groups. Antibody levels were higher in the asthmatic group as compared to the non-asthmatic subjects. Six weeks after infection with RV16, IgG1 antibodies showed a group-specific increase towards the N-terminal VP1 fragment, but not towards other capsid and non-structural proteins, which was highest in subjects with severe upper and lower respiratory symptoms. Interpretation Our results demonstrate that increases of antibodies towards the VP1 N-terminus are group-specific and associated with severity of respiratory symptoms and suggest that it may be possible to develop serological tests for identifying causative RV groups.

Comparison of the immunogenicity of BM32, a recombinant hypoallergenic B cell epitope–based grass pollen allergy vaccine with allergen extract–based vaccines

Allergen-specific immunotherapy (AIT) is a clinically and cost-effective allergy treatment that modifies the course of the disease and has long-lasting effects.1,E7,E8 However, allergen extract–based forms of AIT require administration of multiple doses, which makes treatment cumbersome and leads to poor compliance in patients.2 A number of approaches were proposed to address this issue, including use of AIT materials with higher safety, such as allergoids, recombinant allergen derivatives, and allergen-derived peptides, which allow shortening of the buildup phase.E9