Identification of Epitopes on Rhinovirus 89 Capsid Proteins Capable of Inducing Neutralizing Antibodies.

Rhinoviruses (RVs) are major causes of the common cold, but they can also trigger exacerbations of asthma. More than 160 different RV strains exist and can be classified into three genetic species (RV-A, RV-B and RV-C) which bind to different receptors on human cells including intracellular adhesion molecule 1 (ICAM-1), the low-density lipoprotein receptor (LDLR) or the cadherin-related family member 3 (CDHR3). Epitopes located in the RV capsid have mainly been determined for RV2, a minor-group RV-A strain binding to LDLR, and for RV14, a major-group RV-B strain binding to ICAM-1. In order to study epitopes involved in the neutralization of RV89, an ICAM-1-binding RV-A strain which is highly different from RV2 and RV14 in terms of receptor specificity and sequence, respectively, we analyzed the specificity and epitopes of a highly neutralizing antiserum using recombinantly produced RV89 capsid proteins (VP1, VP2, VP3 and VP4), recombinant fragments and synthetic overlapping peptides thereof. We found that the antiserum which neutralized in vitro RV89 infection up to a dilution of 1:24,000 reacted with the capsid proteins VP1 and VP2 but not with VP3 and VP4. The neutralizing antibodies recognized recombinant fragments comprising approximately 100 amino acids of the N- and C-terminus of VP1 and the middle part of VP2, in particular, three peptides which, according to molecular modeling based on the three-dimensional structure of RV16, were surface-exposed on the viral capsid. Two recombinant fusion proteins containing the identified peptides fused to hepatitis B (HBV)-derived preS as a carrier protein induced upon immunization of rabbits antibodies capable of neutralizing in vitro RV89 infections. Interestingly, the virus-neutralizing epitopes determined for RV89 corresponded to those determined for minor-group RV2 binding to LDL and major-group RV14 belonging to the RV-B species, which are highly different from RV89. Our results indicate that highly different RV strains, even when reacting with different receptors, seem to engage similar parts of their capsid in the infection process. These results may be important for the design of active and passive immunization strategies for RV.

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.

Toward personalization of asthma treatment according to trigger factors.

Asthma is a severe and chronic disabling disease affecting more than 300 million people worldwide. Although in the past few drugs for the treatment of asthma were available, new treatment options are currently emerging, which appear to be highly effective in certain subgroups of patients. Accordingly, there is a need for biomarkers that allow selection of patients for refined and personalized treatment strategies. Recently, serological chip tests based on microarrayed allergen molecules and peptides derived from the most common rhinovirus strains have been developed, which may discriminate 2 of the most common forms of asthma, that is, allergen- and virus-triggered asthma. In this perspective, we argue that classification of patients with asthma according to these common trigger factors may open new possibilities for personalized management of asthma.

Oxidative Stress Markers and Their Dynamic Changes in Patients after Acute Ischemic Stroke.

We have focused on determining the range of oxidative stress biomarkers and their dynamic changes in patients at different time points after the acute ischemic stroke (AIS). 82 patients with AIS were involved in our study and were tested: within 24 h from the onset of the attack (group A); at 7-day follow-up (group B); and at 3-month follow-up (group C). 81 gender and age matched volunteers were used as controls. Stroke patients in group A had significantly higher concentrations of plasma lipid peroxides and urine 8-isoprostanes when compared with controls. Protein carbonyls were not significantly different in any experimental group compared to controls. Antioxidant capacity of plasma was increased only in experimental group C. Activities of superoxide dismutase and catalase were elevated in all three experimental AIS groups compared to controls. Paraoxonase activity was reduced in groups A and B and unchanged in group C when compared to controls. Glutathione peroxide activity was elevated only in group A. Our results suggest that free radical damage is the highest within 24 h after the attack. During the next 3 months oxidative damage to lipids caused by free radicals is reduced due to activated antioxidant system.