Generation of Simian Rotavirus Reassortants with VP4- and VP7-Encoding Genome Segments from Human Strains Circulating in Africa Using Reverse Genetics.

Alexander Falkenhagen,Amy Strydom,Corinna Patzina-Mehling,Reimar Johne,Hester G O’Neill,Ashish K Gadicherla

doi:10.3390/v12020201

Alexander Falkenhagen, Amy Strydom + Show 4 more

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https://doi.org/10.3390/v12020201

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Abstract

Human rotavirus A (RVA) causes acute gastroenteritis in infants and young children. The broad use of two vaccines, which are based on RVA strains from Europe and North America, significantly reduced rotavirus disease burden worldwide. However, a lower vaccine effectiveness is recorded in some regions of the world, such as sub-Saharan Africa, where diverse RVA strains are circulating. Here, a plasmid-based reverse genetics system was used to generate simian RVA reassortants with VP4 and VP7 proteins derived from African human RVA strains not previously adapted to cell culture. We were able to rescue 1/3 VP4 mono-reassortants, 3/3 VP7 mono-reassortants, but no VP4/VP7 double reassortant. Electron microscopy showed typical triple-layered virus particles for the rescued reassortants. All reassortants stably replicated in MA-104 cells; however, the VP4 reassortant showed significantly slower growth compared to the simian RVA or the VP7 reassortants. The results indicate that, at least in cell culture, human VP7 has a high reassortment potential, while reassortment of human VP4 from unadapted human RVA strains with simian RVA seems to be limited. The characterized reassortants may be useful for future studies investigating replication and reassortment requirements of rotaviruses as well as for the development of next generation rotavirus vaccines.

Highlights

Rotavirus A (RVA) is the main causative agent of acute viral gastroenteritis in children under5 years of age
VP4- and VP7-encoding genome segments of three RVA strains from sub-Saharan Africa were selected based on their genetic diversity and the availability of full-length genome sequences
The recently established reverse genetics systems (RGS) for RVA enable a targeted generation of viable reassortants as recently shown for SA11 containing VP4-encoding genome segments from diverse animal RVAs [31]

Summary

Introduction

Rotavirus A (RVA) is the main causative agent of acute viral gastroenteritis in children under5 years of age. Rotavirus A (RVA) is the main causative agent of acute viral gastroenteritis in children under. Dehydration caused by severe diarrhea or vomiting can become life-threatening and it is estimated that rotavirus infections resulted in 128,500 deaths in 2016, of which 104,733 occurred in sub-Saharan Africa [1]. RVA is a non-enveloped virus with a double-stranded RNA (dsRNA) genome consisting of eleven segments encoding six structural viral proteins (VPs) and six non-structural proteins (NSPs) [2]. The middle and outer layer are formed by VP6 and VP7, respectively. VP4 forms spikes that are anchored in a cavity formed by VP6 and VP7 and protrude from the outer layer [3]. VP4 mediates entry into host cells and must undergo tryptic cleavage to acquire efficient infectivity for susceptible cells [4].

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