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.

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 20 mer 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.

BackgroundIgE-allergen complexes induce mast cell and basophil activation and thus immediate allergic inflammation. They are also important for IgE-facilitated allergen presentation to T cells by antigen-presenting cells.ObjectiveTo investigate whether the proximity of IgE binding sites on an allergen affects immune complex shape and subsequent effector cell activation in vitro and in vivo.MethodsWe constructed artificial allergens by grafting IgE epitopes in different numbers and proximity onto a scaffold protein. The shape of immune complexes formed between artificial allergens and the corresponding IgE was studied by negative-stain electron microscopy. Allergenic activity was determined using basophil activation assays. Mice were primed with IgE, followed by injection of artificial allergens to evaluate their in vivo allergenic activity. Severity of systemic anaphylaxis was measured by changes in body temperature.ResultsWe could demonstrate simultaneous binding of 4 IgE antibodies in close vicinity to each other. The proximity of IgE binding sites on allergens influenced the shape of the resulting immune complexes and the magnitude of effector cell activation and in vivo inflammation.ConclusionsOur results demonstrate that the proximity of IgE epitopes on an allergen affects its allergenic activity. We thus identified a novel mechanism by which IgE-allergen complexes regulate allergic inflammation. This mechanism should be important for allergy and other immune complex–mediated diseases.

Antibody response to recombinant RV VP1 proteins was associated with longer time with respiratory symptoms.

BackgroundRhinoviruses (RVs) are a major cause of common colds and induce exacerbations of asthma and chronic inflammatory lung diseases.MethodsWe 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.FindingsBefore 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.InterpretationOur 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.