Zebrafish as a Model for the Study of Host-Virus Interactions.

Zebrafish (Danio rerio) has become an increasingly important model for in vivo and in vitro studies on host-pathogen interaction, offering scientists with optical accessibility and genetic tractability, and a vertebrate-type immunity that can be separated into innate and adaptive ones. Although it is shown in previous studies that few species of viruses can naturally infect zebrafish, the spring viraemia of carp virus (SVCV), a rhabdovirus that causes contagious acute hemorrhagic viraemia in a variety of cyprinid fishes, can infect zebrafish by both injection and static immersion methods in laboratory conditions. In addition, SVCV can infect zebrafish fibroblast cell line (ZF4 cells), together with the Epithelioma papulosum cyprini (EPC) cell line (EPC cells), a common cell line used widely in fish disease research. The infection and propagation of SVCV in zebrafish and especially in these cell lines can be employed conveniently in laboratory for functional assays of zebrafish genes. The zebrafish, ZF4 and EPC cell, and SVCV can serve as a simple and efficient model system in understanding host-virus interactions. In the present chapter, we provide detailed protocols for the host-virus interaction analysis based on zebrafish embryos, ZF4/EPC cells, and SVCV, including infection methods of zebrafish embryos and cell lines, analyses of immune responses by quantitative PCR (qPCR) and RNA sequencing (RNA-Seq), antiviral assays based on ZF4 and EPC cells, and the analysis of host-virus interaction using luciferase assays. These protocols should provide efficient and typical means to address host-virus interactions in a more general biological sense.