Rhinovirus

Structure of Rhinovirus

h3 Rhinovirus is a positive-sense, single-stranded RNA virus belonging to the Enterovirus genus in the family Picornaviridae. The viral genome is approximately 7.2 kb in size with a single open reading frame that functions as a messenger RNA. The translated protein is cleaved by virally encoded proteases to produce 11 proteins. Human rhinovirus (HRV) is a small particle with a diameter of 25-30 nm and possesses a non-enveloped icosahedral capsid consisting of 60 copies of each of the four capsid proteins (VP1-4). Antigenic variation among HRV types is derived from variations in the exposed surface of VP1, VP2, and VP3, while embedded VP4 is responsible for RNA packaging during assembly. HRVs are classified into three species, HRV-A, HRV-B, and HRV-C and one-hundred one serotypes have been detected. One striking characteristic of HRVs is the ability to replicate rapidly and demonstrate high mutation rates, resulting in distinct genetic diversity. The Rhinovirus genus contains more than 150 recognized serotypes, hence the difficulty in producing a vaccine.

Fig.1 HRV genomic organization, virion structure, and species. (Savolainen, 2003)

Pathogenesis

h3 In the respiratory tract, HRVs, like most respiratory viruses, mainly replicate in the ciliary epithelial cells (EC) of the nasal mucosa and, to a lesser extent, in the oral cavity and throat. More than 90% of known HRV serotypes, the “major group,” utilize the cell surface receptor intercellular adhesion molecule 1 (ICAM-1) to bind and infect the cell, while the “minor group” attaches to and enters cells via the low-density lipoprotein receptor (LDLR). In addition, HRV infection induces the expression of ICAM-1 to further the availability of receptors for HRV. Following infection, airway bronchial ECs produce a variety of cytokines and chemokines that promote the recruitment and activation of inflammatory and immuno-effector cells to serve the host antiviral response. The subsequent release of cytokines and chemokines results in an amplification of the inflammatory response to infection, presenting with symptomatic colds and asthma exacerbations. The inflammatory and immune responses facilitate the clearance of the virus but also amplify pre-existing inflammation and contribute to disease exacerbation.

Fig.2 EC response to rhinovirus infection. (Stobart, 2017)

Epidemiology

HRVs are transmitted from person to person via contact (either direct or through a fomite) or aerosol (small or large particle).  HRVs are responsible for most episodes of the common cold in all age groups. However, a higher infection rate is most commonly involved in older infants, preschool-aged and school-aged children and adolescents, as well as in elderly and immunocompromised adults. HRVs cause respiratory illness throughout the world and throughout the year. In general, a higher incidence of HRV infection has been described from September to November and from April to May, but in some years (and in some geographical areas) spring was reported to be the more important time for HRV transmission.

Symptoms

In most cases, HRVs cause mild upper respiratory tract infections, that are associated with common cold-like symptoms including rhinorrhea, sore throat, coughing, sneezing, nasal congestion, and general malaise. On the other hand, infections of the lower respiratory tract can cause severe symptoms and result in bronchiolitis, pneumonia, and exacerbation of asthma.

Prevention and Treatment

As with many other viruses, no commonly used treatment acts on the HRV infection especially. Treatment for HRV usually means managing the symptoms until the infection clears. In practice, symptomatic treatment of the common cold is still a useful approach. However, bronchiolitis, pneumonia, or other complications of HRV infection may require medication and monitoring. As for the prophylaxis of HRV, the development of a vaccine against HRV infection may be unrealizable because of a vast number of HRV serotypes.

Based on world-leading technology and antibody platforms, Creative Biolabs is committed to providing a series of antibody services. We provide a series of anti-Rhinovirus antibodies for hot targets including VP2, VP3, 3C protease, capsid protein, etc. Our services are built to meet the customer’s projects and tailored demands. Please feel free to contact us.

References

1. Stobart C.C.; et al. Rhinovirus Biology, Antigenic Diversity, and Advancements in the Design of a Human Rhinovirus Vaccine. Front Microbiol. 2017, 8: 2412.
2. Kelly J.; et al. Host immune responses to rhinovirus: Mechanisms in asthma. Journal of Allergy & Clinical Immunology. 2008, 122(4):671-682.

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