Establishment of a #Cell #Culture Model of Persistent #Flaviviral #Infection: #Usutu Virus Shows Sustained Replication during Passages and Resistance to Extinction by Antiviral Nucleosides (Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Viruses. 2019 Jun 17;11(6). pii: E560. doi: 10.3390/v11060560.

Establishment of a Cell Culture Model of Persistent Flaviviral Infection: Usutu Virus Shows Sustained Replication during Passages and Resistance to Extinction by Antiviral Nucleosides.

Sempere RN1,2, Arias A3.

Author information: 1 Life Science & Bioengineering Building, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. rnsempere@abiopep.com. 2 Abiopep Sociedad Limitada, Parque Científico de Murcia, 30100 Murcia, Spain. rnsempere@abiopep.com. 3 Life Science & Bioengineering Building, Technical University of Denmark, 2800 Kongens Lyngby, Denmark. aaesteban2@gmail.com.

 

Abstract

Chronic viral disease constitutes a major global health problem, with several hundred million people affected and an associated elevated number of deaths. An increasing number of disorders caused by human flaviviruses are related to their capacity to establish a persistent infection. Here we show that Usutu virus (USUV), an emerging zoonotic flavivirus linked to sporadic neurologic disease in humans, can establish a persistent infection in cell culture. Two independent lineages of Vero cells surviving USUV lytic infection were cultured over 82 days (41 cell transfers) without any apparent cytopathology crisis associated. We found elevated titers in the supernatant of these cells, with modest fluctuations during passages but no overall tendency towards increased or decreased infectivity. In addition to full-length genomes, viral RNA isolated from these cells at passage 40 revealed the presence of defective genomes, containing different deletions at the 5′ end. These truncated transcripts were all predicted to encode shorter polyprotein products lacking membrane and envelope structural proteins, and most of non-structural protein 1. Treatment with different broad-range antiviral nucleosides revealed that USUV is sensitive to these compounds in the context of a persistent infection, in agreement with previous observations during lytic infections. The exposure of infected cells to prolonged treatment (10 days) with favipiravir and/or ribavirin resulted in the complete clearance of infectivity in the cellular supernatants (decrease of ~5 log10 in virus titers and RNA levels), although modest changes in intracellular viral RNA levels were recorded (<2 log10 decrease). Drug withdrawal after treatment day 10 resulted in a relapse in virus titers. These results encourage the use of persistently-infected cultures as a surrogate system in the identification of improved antivirals against flaviviral chronic disease.

KEYWORDS: antiviral therapies; chronic viral infection; defective viral genomes; emerging arboviruses; lethal mutagenesis

PMID: 31212939 DOI: 10.3390/v11060560

Keywords: Flavivirus; Usutu virus; Antivirals; Favipiravir; Ribavirin.

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gimi69

I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.

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