Propagation of infectious salmon anaemia (ISA) virus in cell culture

A long-term cell line supporting growth of the infectious salmon anaemia (ISA) virus has been established. The cell line (SHK-1) was developed from a culture of head kidney leucocytes from Atlantic salmon, and exhibited macrophage-like enzyme reactivities. By means of transmission experiments, ISA infectivity of cell culture medium could be demonstrated from day 5 after infection of SHK-1 cells with ISA-infective tissue homogenate. ISA infectivity of cell culture medium increased following repeated passages of virus. ISA-infected cell cultures develop cytopathic effects (CPE), making quantitation of virus possible. The development of CPE in ISA virus infected cells was inhibited by ammonium chloride, chloroquine and bafilomycin A, suggesting that infection of SHK-1 cells with ISA virus requires a low-pH step.