Distinct immune responses of juvenile and adult oysters (Crassostrea gigas) to viral and bacterial infections

• Published in: BMC veterinary research 2016-07, Vol.47 (1), p.72-72, Article 72
• Main Authors: Green, Timothy J, Vergnes, Agnes, Montagnani, Caroline, de Lorgeril, Julien
• Format: Article
• Language: English
• Subjects: Age Factors; Animals; Biodiversity; Crassostrea; Crassostrea - genetics; Crassostrea - immunology; Crassostrea - microbiology; Crassostrea - virology; Health aspects; Herpes; Herpesviridae - immunology; Herpesviridae Infections - immunology; Herpesviridae Infections - veterinary; Herpesviridae Infections - virology; Herpesvirus diseases; Immune response; Life Sciences; Medical research; Observations; Oysters; Physiological aspects; Polymerase Chain Reaction - methods; Populations and Evolution; Veterinary medicine; Vibrio - immunology; Vibrio infections; Vibrio Infections - immunology; Vibrio Infections - microbiology; Vibrio Infections - veterinary
• ISSN: 1297-9716; 0928-4249; 1746-6148; 1297-9716; 1746-6148
• DOI: 10.1186/s13567-016-0356-7

Since 2008, massive mortality events of Pacific oysters (Crassostrea gigas) have been reported worldwide and these disease events are often associated with Ostreid herpesvirus type 1 (OsHV-1). Epidemiological field studies have also reported oyster age and other pathogens of the Vibrio genus are contributing factors to this syndrome. We undertook a controlled laboratory experiment to simultaneously investigate survival and immunological response of juvenile and adult C. gigas at different time-points post-infection with OsHV-1, Vibrio tasmaniensis LGP32 and V. aestuarianus. Our data corroborates epidemiological studies that juveniles are more susceptible to OsHV-1, whereas adults are more susceptible to Vibrio. We measured the expression of 102 immune-genes by high-throughput RT-qPCR, which revealed oysters have different transcriptional responses to OsHV-1 and Vibrio. The transcriptional response in the early stages of OsHV-1 infection involved genes related to apoptosis and the interferon-pathway. Transcriptional response to Vibrio infection involved antimicrobial peptides, heat shock proteins and galectins. Interestingly, oysters in the later stages of OsHV-1 infection had a transcriptional response that resembled an antibacterial response, which is suggestive of the oyster's microbiome causing secondary infections (dysbiosis-driven pathology). This study provides molecular evidence that oysters can mount distinct immune response to viral and bacterial pathogens and these responses differ depending on the age of the host.