“Pacific oyster explants provide new controlled model to study OsHV-1 replication (7203)”

Pacific oyster explants provide new controlled model to study OsHV-1 replication

Since the 1990s, Pacific oysters (Magallana gigas), particularly juveniles, have experienced recurrent mass mortality events. These events are strongly associated with infection by Ostreid herpesvirus type 1 (OsHV-1), a major viral pathogen that causes significant economic losses in oyster aquaculture. Despite the importance of this disease, our understanding of the mechanisms underlying viral infection and the host immune response remains limited, largely due to the lack of established marine mollusc cell lines.

Recently, the use of oyster tissue explants has emerged as a promising alternative, providing a system that mimics primary cell culture conditions.

In this study, gill explants were cultured in vitro and experimentally infected with OsHV-1. We monitored infection dynamics over 48 hours and assessed the effects of the virus on tissue structure and integrity by direct observation. Explants were also sampled at defined time points for OsHV-1 quantification by qPCR, as well as for DNA and cDNA long-read Nanopore sequencing.

Our results show that OsHV-1 can replicate in gill explants, providing a controlled system for studying viral replication dynamics. We successfully reassembled complete OsHV-1 genomes from infected explants and observed gene expression kinetics that closely mimic those reported in in vivo studies. This explant model provides a valuable approach to study host-pathogen interactions in M. gigas under controlled conditions and offers new insights into tissue-specific immune responses to OsHV-1.

1. Dotto-Maurel, Aurélie, Ifremer, Presenter
2. Sullivan, Kallen, Roslin Institute, Author
3. Morga, Benjamin, Ifremer, Author
4. Bean, Tim, Roslin Institute, Author
5. Chevignon, Germain, Ifremer, Author