Abstract

The recent emergence of Zika virus (ZIKV) in the Americas coincident with increased caseloads of microcephalic infants and Guillain-Barre syndrome has prompted a flurry of research on ZIKV. Much of the research is difficult to compare or repeat because individual laboratories use different virus isolates, growth conditions, and quantitative assays. Here we obtained three readily available contemporary ZIKV isolates and the prototype Ugandan isolate. We generated stocks of each on Vero mammalian cells (ZIKVmam) and C6/36 mosquito cells (ZIKVmos), determined titers by different assays side-by-side, compared growth characteristics using one-step and multi-step growth curves on Vero and C6/36 cells, and examined plaque phenotype. ZIKV titers consistently peaked earlier on Vero cells than on C6/36 cells. Contemporary ZIKV isolates reached peak titer most quickly in a multi-step growth curve when the amplifying cell line was the same as the titering cell line (e.g., ZIKVmam titered on Vero cells). Growth of ZIKVmam on mosquito cells was particularly delayed. These data suggest that the ability to infect and/or replicate in insect cells is limited after growth in mammalian cells. In addition, ZIKVmos typically had smaller, more homogenous plaques than ZIKVmam in a standard plaque assay. We hypothesized that the plaque size difference represented early adaptation to growth in mammalian cells. We plaque purified representative-sized plaques from ZIKVmos and ZIKVmam. ZIKVmos isolates maintained the initial phenotype while plaques from ZIKVmam isolates became larger with passaging. Our results underscore the importance of the cells used to produce viral stocks and the potential for adaptation with minimal cell passages. In addition, these studies provide a foundation to compare current and emerging ZIKV isolates in vitro and in vivo.

Highlights

  • Zika virus (ZIKV) is a mosquito-borne virus in the genus Flavivirus, which includes many arthropod-borne viruses such as dengue virus (DENV) and West Nile virus (WNV)

  • The ZIKV scientific field has greatly expanded since the emergence of ZIKV in South and Central America, but a comprehensive comparison of the assays used to examine the phenotypic and replicative properties of ZIKV is limited in the literature

  • ZIKV seed stocks were amplified by a single passage on mammalian or mosquito cells, resulting in two stocks of each isolate: one grown on Vero cells (ZIKVmam) and one grown on C6/36 cells (ZIKVmos)

Read more

Summary

Introduction

Zika virus (ZIKV) is a mosquito-borne virus in the genus Flavivirus, which includes many arthropod-borne viruses (arboviruses) such as dengue virus (DENV) and West Nile virus (WNV). It was originally isolated in 1947 from a sentinel macaque in Uganda and was subsequently found throughout Africa and Asia with minimal reports of disease [1,2,3,4,5,6]. ZIKV emerged explosively in Brazil in 2015 [10] with estimates of over 1.5 million infections [11] and quickly spread throughout South and Central America and the Caribbean with 84 countries reporting local mosquito transmission (WHO situation report, 10 March 2017). The extensive geographic range of ZIKV and severe congenital abnormalities in infants born to ZIKVinfected mothers have resulted in a worldwide public health concern

Methods
Results
Discussion
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call