Susceptibility of CCB cell line to different fish viruses

摘要

In spite of the establishment of modern techniques like PCR for virus detection, virus isolations in susceptible fish cell lines are still the basis for international certification of most notifiable viral fish diseases mentioned by the OIE and the European Union (OIE, 2000; European Commission, 1996). Cell cultures may change in susceptibility (Lorenzen et al., 1999, unpublished own findings,). If no regular susceptibility checks are done in the laboratory, using an alternative sensitive cell culture might therefore increase the chance of isolating a certain virus. The CCB (common carp brain) cell line, developed by and cultured according to Neukirch et al., 1999, was originally developed for the diagnosis of koi herpesvirus (KHV). Moreover, we isolated other viruses from diseased koi in CCB cells. Besides KHV, myxoviruses, birna- and/or reoviruses (not all isolates were identified) and rhabdoviruses (spring viraemia of carp virus, SVCV) were obtained (Neukirch Kunz, 2001). The susceptibility of CCB cells was also investigated for viruses isolated from golden ide, European eel and salmonids. CCB cells and the standard cell lines used in our laboratory: Epithelioma papulosum cyprinid, EPC (Tomasec and Fijan, 1971), Chinook Salmon Embryo, CHSE (Fryer et al., 1965) and Eel kidney, EK-1 (Chen et al., 1982) for the different viruses were inoculated with the following viruses: infectious pancreatic necrosis virus (IPNV, strains Sp, Ab and Ni), viral haemorrhagic septicaemia virus (VHSV, serotype I, II and III), infectious haematopoietic necrosis virus (IHNV), golden ide reovirus (GiRV), chum salmon reovirus (CSV), herpesvirus anguillae (HVA), and another eel virus designated A sub(1)B virus. Non-infected cell lines were incubated as negative controls. Two passages were carried out in the cell lines before quantification of virus infectivity by titration of supernatants in 10-fold dilution steps (Mayr et al., 1977). Table 1 summarizes the inoculated viruses used, and results concerning titration of virus infectivity obtained in both the routine cell lines and the CCB cell line.