Cellular and molecular immune responses of the sea bass (Dicentrarchus labrax) experimentally infected with betanodavirus.

Abstract

Naïve sea bass juveniles (38.4 + or - 4.5 g) were intramuscularly infected with a sublethal dose of betanodavirus isolate 378/I03, followed after 43 days by a similar boosting. This infection resulted in an overall mortality of 7.6%. At various intervals, sampling of fish tissues was performed to investigate: i) B and T lymphocyte content in organs and tissues; ii), proliferation of leucocytes re-stimulated in vitro with inactivated virus; iii) presence of serum antibody specific for betanodavirus; iv) expression of genes coding for the following immunoregulatory molecules involved in innate and acquired responses: type I IFN, Mx, IL-1, Cox-2; IL-10, TGF-beta, TCRbeta, CD4, CD8alpha, IgM, by using a quantitative PCR array system developed for sea bass. The obtained results showed a detectable increase of T cells and B cells in PBL during betanodavirus infection. Furthermore, leucocytes obtained from blood, head kidney, and gills showed a detectable "in vitro" increase in viability upon addition of inactivated viral particles, as determined by measuring intracellular ATP concentration. ELISA analysis of sera showed that exposure to nodavirus induced a low, but specific antibody titer measured 43 days after infection, despite the presence of measurable levels of natural antibody. Finally, a strong upregulation of genes coding for type I IFN, Mx, and IgM was identified after both infection and boosting. Interestingly, an upregulation of Cox-2 until boosting, and of TGF-beta and IL-10 after boosting was also observed, while the other tested genes did not show any significant variations with respect to mock-treated fish. Overall, our work represents a first comprehensive analysis of cellular and molecular immune parameters in a fish species exposed to a pathogenic virus.

• Authors: G Scapigliati, F Buonocore, E Randelli, D Casani, S Meloni, G Zarletti, M Tiberi, D Pietretti, I Boschi, M Manchado, B Martin-Antonio, R Jimenez-Cantizano, G Bovo, F Borghesan, N Lorenzen, K Einer-Jensen, S Adams, K Thompson, C Alonso, J Bejar, I Cano, J J Borrego, M C Alvarez
• Journal: Fish & shellfish immunology (Fish Shellfish Immunol) Vol. 28 Issue 2 Pg. 303-11 (Feb 2010) ISSN: 1095-9947 [Electronic] England
• PMID: 19925869 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2009 Elsevier Ltd. All rights reserved.

Chemical References

• Antibodies, Viral

Topics

• Animals
• Antibodies, Viral (blood)
• Bass (immunology, virology)
• Cell Line
• Cell Proliferation
• Enzyme-Linked Immunosorbent Assay
• Fish Diseases (immunology, virology)
• Lymphocytes (cytology)
• Nodaviridae (immunology)
• Polymerase Chain Reaction
• RNA Virus Infections (immunology, veterinary)