RESUMO
Segment A of the Sp strain (a Norwegian field isolate) of infectious pancreatic necrosis virus (IPNV) was amplified by reverse transcriptase polymerase chain reaction in two stages from RNA isolated from infected cells, and cloned into the Semliki Forest virus (SFV) expression vector pSFV1. Expression and correct processing of IPNV proteins was confirmed by transfection of RNA transcribed from this plasmid into BHK cells. This clone was then used to produce recombinant replication-defective SFV particles (rSFV) expressing the IPNV segment A. Immunofluorescence studies with conformation-dependent monoclonal antibodies to IPNV confirmed that the recombinant proteins produced after infection of the salmonid cell line CHSE-214 with such rSFV retain their antigenicity. Infection of the CHSE cells with the rSFV resulted in the formation of IPNV-like particles, which were similar in size and morphology to IPNV.
