Isolation and Characterization of Clinical RSV Isolates in Belgium during the Winters of 2016-2018.

Winke Van Der Gucht,Guy Caljon,Annemieke Smet,Steven Van Gucht,Jozef De Dooy,Matthias Govaerts,Stijn Verhulst,Kim Stobbelaar,Peter L Delputte,Benedicte De Winter,Paul Cos,Louis Maes,Annelies Leemans,Philippe Jorens,Cyril Barbezange,Thomas Mangodt

doi:10.3390/v11111031

Winke Van Der Gucht, Guy Caljon + Show 14 more

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https://doi.org/10.3390/v11111031

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Abstract

Respiratory Syncytial Virus (RSV) is a very important viral pathogen in children, immunocompromised and cardiopulmonary diseased patients and the elderly. Most of the published research with RSV was performed on RSV Long and RSV A2, isolated in 1956 and 1961, yet recent RSV isolates differ from these prototype strains. Additionally, these viruses have been serially passaged in cell culture, which may result in adaptations that affect virus–host interactions. We have isolated RSV from mucosal secretions of 12 patients in the winters 2016–2017 and 2017–2018, of which eight RSV-A subtypes and four RSV-B subtypes. Passage 3 of the isolates was assessed for viral replication kinetics and infectious virus production in HEp-2, A549 and BEAS-2B cells, thermal stability at 37 °C, 32 °C and 4 °C, syncytia formation, neutralization by palivizumab and mucin mRNA expression in infected A549 cells. We observed that viruses isolated in one RSV season show differences on the tested assays. Furthermore, comparison with RSV A2 and RSV B1 reveals for some RSV isolates differences in viral replication kinetics, thermal stability and fusion capacity. Major differences are, however, not observed and differences between the recent isolates and reference strains is, overall, similar to the observed variation in between the recent isolates. One clinical isolate (BE/ANT-A11/17) replicated very efficiently in all cell lines, and remarkably, even better than RSV A2 in the HEp-2 cell line.

Highlights

Respiratory Syncytial Virus (RSV), recently renamed to human orthopneumovirus, is a very important viral respiratory pathogen in infants, children and adult patients with immunodeficiency or cardiopulmonary disease and it is recognized as a major threat for the elderly population [1,2,3,4,5,6]
RSV-A was detected in one sample of December 2016 and in 11 samples collected between October 2017 and January 2018
HEp-2 cells were used for isolation since they are permissive for most RSV

Summary

Introduction

Respiratory Syncytial Virus (RSV), recently renamed to human orthopneumovirus, is a very important viral respiratory pathogen in infants, children and adult patients with immunodeficiency or cardiopulmonary disease and it is recognized as a major threat for the elderly population [1,2,3,4,5,6]. Palivizumab, which is solely used for passive immunization of high-risk infants, targets a specific, highly conserved epitope on the fusion protein [8,9], resulting in fusion inhibition. RSV is classified in the family Pneumoviridae, genus Orthopneumovirus and can be divided into two subtypes, RSV-A and RSV-B It has a non-segmented, negative, single-stranded RNA genome that consists of ten genes, encoding 11 proteins. The protein consists of a central conserved domain, two glycosylated mucin-like regions and an N-terminal region containing a transmembrane domain and a cytoplasmic domain [10,11]. The two mucin-like regions serve as excellent targets for RSV evolution studies. Both subtypes are further divided into genotypes based on those genetic variations. The formation of syncytia is recognized as a means to efficiently spread the infection along epithelial surfaces, while minimizing contact with the immune system [27]

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