title: 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.affiliation: Dipartimento di Scienze Ambientali, Largo dell'Università, Università degli Studi della Tuscia, Viterbo 01100, Italy. scapigg@unitus.it
authors.forename: G
authors.initials: G
authors.lastname: Scapigliati
authors.forename: F
authors.initials: F
authors.lastname: Buonocore
authors.forename: E
authors.initials: E
authors.lastname: Randelli
authors.forename: D
authors.initials: D
authors.lastname: Casani
authors.forename: S
authors.initials: S
authors.lastname: Meloni
authors.forename: G
authors.initials: G
authors.lastname: Zarletti
authors.forename: M
authors.initials: M
authors.lastname: Tiberi
authors.forename: D
authors.initials: D
authors.lastname: Pietretti
authors.forename: I
authors.initials: I
authors.lastname: Boschi
authors.forename: M
authors.initials: M
authors.lastname: Manchado
authors.forename: B
authors.initials: B
authors.lastname: Martin-Antonio
authors.forename: R
authors.initials: R
authors.lastname: Jimenez-Cantizano
authors.forename: G
authors.initials: G
authors.lastname: Bovo
authors.forename: F
authors.initials: F
authors.lastname: Borghesan
authors.forename: N
authors.initials: N
authors.lastname: Lorenzen
authors.forename: K
authors.initials: K
authors.lastname: Einer-Jensen
authors.forename: S
authors.initials: S
authors.lastname: Adams
authors.forename: K
authors.initials: K
authors.lastname: Thompson
authors.forename: C
authors.initials: C
authors.lastname: Alonso
authors.forename: J
authors.initials: J
authors.lastname: Bejar
authors.forename: I
authors.initials: I
authors.lastname: Cano
authors.forename: J J
authors.initials: JJ
authors.lastname: Borrego
authors.forename: M C
authors.initials: MC
authors.lastname: Alvarez
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001492:Bass / Q000276:immunology* / Q000821:virology*; D002460:Cell Line; D049109:Cell Proliferation; D004797:Enzyme-Linked Immunosorbent Assay; D005393:Fish Diseases / Q000276:immunology* / Q000821:virology; D008214:Lymphocytes / Q000166:cytology; D030381:Nodaviridae / Q000276:immunology*; D016133:Polymerase Chain Reaction; D012327:RNA Virus Infections / Q000276:immunology / Q000662:veterinary*
chemical_list: D000914:Antibodies, Viral