ESTABLISHMENT AND CHARACTERIZATION OF A CELL-LINE PERSISTENTLY INFECTED WITH INFECTIOUS PANCREATIC NECROSIS VIRUS (IPNV)

The present study characterizes a new cell line (designated SB) establ ished from the swim bladder of the black carp, Mylopharyngodon piceus. The SB cell line lost contact inhibition with high plating efficiency and anchorage independence from the beginning of the primary culture. Icosahedral viral particles and inclusion bodies were found in the cy toplasm of some SB cells which lacked viral inoculation, suggesting th at the viruses originated from persistent viral-infected cells of the fish. After treatment with chloroform and the metabolic inhibitor 5-fl uoro-2'-deoxyuridine (FUDR), the virus proved to be a non-enveloped RN A virus. Results from an analysis of purified viral nucleic acid also indicated that this virus was an RNase A resistant, bi-segmented doubl e-stranded RNA virus. The supposition that the virus was a mutant of t he Infectious Pancreatic Necrosis Virus (IPNV) Ab serotype arose after the presumptive serotyping of the viral antigen by both polyclonal an d monoclonal antibodies.