Differential suppression of persistent insect specific viruses in trans-infected wMel and wMelPop-CLA Aedes-derived mosquito lines

Breeanna J Mclean,Kimberley R Dainty,Heather A Flores,Scott L O’Neill

doi:10.1016/j.virol.2018.11.012

Abstract

Wolbachia suppresses the replication of +ssRNA viruses such as dengue and Zika viruses in Aedes aegypti mosquitoes. However, the range of viruses affected by this endosymbiont is yet to be explored. Recently, novel insect-specific viruses (ISVs) have been described from numerous mosquito species and mosquito-derived cell lines. Cell-fusing agent virus (Flaviviridae) and Phasi Charoen-like virus (Bunyaviridae) persistently infect the Ae. aegypti cell line Aag2 which has been used for experimental studies with both the wMel and wMelPop-CLA strains. Wolbachia was found to restrict the replication of CFAV but not the PCLV infection in these lines. Furthermore, an additional Ae. albopictus cell line (RML-12) which contained either wMel or wMelPop-CLA was assessed. While no infectious +ssRNA or dsRNA viruses were detected, a PCLV infection was identified. These observations provide additional evidence to support that insect-specific, +ssRNA viruses can be suppressed in cell culture by Wolbachia but -ssRNA viruses may not.

Highlights

Arthropod-borne viruses are a diverse group of mosquito, sand-fly and tick transmitted pathogens responsible for significant diseases in humans
While a significant amount of data has been accumulated on the effects of Wolbachia on transmission of major arboviruses from the Flaviviridae and Togaviridae families, relatively little is known about the taxonomic limits of virus blocking by Wolbachia (Aliota et al, 2016; Glaser and Meola, 2010; Moreira et al, 2009; Shaw et al, 2012)
Wolbachia restricts the replication of the +ssRNA virus, Cell fusing agent virus (CFAV), but not –ssRNA virus, Phasi Charoen-like virus (PCLV), in co-infected cell culture

Summary

Introduction

Arthropod-borne viruses are a diverse group of mosquito, sand-fly and tick transmitted pathogens responsible for significant diseases in humans. The intracellular endosymbiont Wolbachia has been shown to significantly suppress the replication of a broad range of viruses in Drosophila models and interestingly retained this pathogen blocking phenotype upon trans-infection into both Aedesderived cell lines and Aedes aegypti mosquitoes (Aliota et al, 2016; Moreira et al, 2009; Teixeira et al, 2008; Walker et al, 2011). While a significant amount of data has been accumulated on the effects of Wolbachia on transmission of major arboviruses from the Flaviviridae and Togaviridae families, relatively little is known about the taxonomic limits of virus blocking by Wolbachia (Aliota et al, 2016; Glaser and Meola, 2010; Moreira et al, 2009; Shaw et al, 2012). As the mechanism of Wolbachiamediated suppression remains poorly understood, +ssRNA viruses which display altered tropism and transmission strategies to that of other pathogenic viruses of the same family are of interest to be assessed for suppression by Wolbachia

Methods

Discussion

Conclusion