Antiviral protection of oyster Crassostrea gigas


AAP « Researcher of the Future » – French Occitanie country – 2014-2017
Project leader: C. Montagnani
Over the past decade, a paradigm shift has emerged in the field of immunology bringing new concepts beyond the commonly accepted cleavage between innate and acquired immunity. Numerous findings have shown that a wide range of invertebrates can develop innate immune memory (called immune priming) leading to improved survival during a second encounter with a pathogen. The PROVIGAS project has undertaken to investigate this phenomenon of immune priming in the oyster Crassostrea gigas. This species is currently the victim of massive recurring mortalities without existing therapeutic treatment. This syndrome, of complex etiology, involves different types of pathogens, including an emerging pathogen, the herpesvirus OsHV-1 μVar. Our results showed that a pre-treatment (priming) with a synthetic double-stranded RNA analogue, called poly (I: C), led to an effective oyster protection (up to 100%) against subsequent exposure to virus in the laboratory but also in the natural environment, during episodes of mortality. This protection has been shown to be persistent over time (up to five months), suggesting the existence of innate immune memory mechanisms. The study of the molecular bases of this phenomenon revealed that this priming was based on the triggering of a large antiviral immune response limiting replication of the virus, thus allowing the protection of oysters. This study thus brought new arguments on these new concepts of innate immune memory but also allowed to identify new applications to limit the occurrence of oyster mortalities. This work highlights the essential contribution of a finalized research to formulate answers to the major current issues relating to the health of marine invertebrates and the rational optimization of aquaculture productions.


© C. Montagnani