Resistance of Black-lip learl oyster, Pinctada margaritifera, to infection by Ostreid herpes virus 1μvar under experimental challenge may be mediated by humoral antiviral activity. Issue 1 (May 2015)

• Record Type: Journal Article
• Authors: Tan, Terence L.S.; Paul-Pont, Ika; Evans, Olivia M.; Watterson, Daniel; Young, Paul; Whittington, Richard; Fougerouse, Angelique; Bichet, Hervé; Barnes, Andrew C.; Dang, Cécile
• Is Part Of: Fish & shellfish immunology. Volume 44:Issue 1(2015:May)
• Page Start: 232
• Page End: 240
• Publication Date: 2015-05
• Subjects: Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2015.02.026
• Languages: English
• ISSNs: 1050-4648

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <p id="abspara0010"> <italic>Ostreid herpesvirus 1</italic> (OsHV-1) has induced mass mortalities of the larvae and spat of Pacific oysters, <italic>Crassostrea gigas</italic>, in Europe and, more recently, in Oceania. The production of pearls from the Black-lip pearl oyster, <italic>Pinctada margaritifera</italic>, represents the second largest source of income to the economies of French Polynesia and many Pacific Island nations that could be severely compromised in the event of a disease outbreak. Coincidentally with the occurrence of OsHV-1 in the southern hemisphere, <italic>C. gigas</italic> imported from New Zealand and France into French Polynesia tested positive for OsHV-1. Although interspecies viral transmission has been demonstrated, the transmissibility of OsHV-1 to <italic>P. margaritifera</italic> is unknown. We investigated the susceptibility of juvenile <italic>P. margaritifera</italic> to OsHV-1 μvar that were injected with tissue homogenates sourced from either naturally infected or healthy <italic>C. gigas</italic>. The infection challenge lasted 14 days post-injection (dpi) with sampling at 0, 1, 2, 3, 5, 7 and 14 days. Mortality rate, viral prevalence, and cellular immune responses in experimental animals were determined. Tissues were screened by light microscopy and TEM. Pacific oysters were also challenged and used as a positive control to validate the efficiency of OsHV-1 μvar infection. Viral particles and features such as marginated chromatin and highly electron dense nuclei were observed in <italic>C. gigas</italic> but not in <italic>P. margaritifera</italic>. Mortality rates and hemocyte immune parameters, including phagocytosis and respiratory burst, were similar between challenged and control <italic>P. margaritifera</italic>. Herpesvirus-inhibiting activity was demonstrated in the acellular fraction of the hemolymph from <italic>P. margaritifera</italic>, suggesting that the humoral immunity is critical in the defence against herpesvirus in pearl oysters. Overall, these results suggest that under the conditions of the experimental challenge, <italic>P. margaritifera</italic> was not sensitive to OsHV-1 μvar and was not an effective host/carrier. The nature and spectrum of activity of the humoral antiviral activity is worthy of further investigation.</p> </sec> </abstract>