DAO 62:45-55 (2004)  -  doi:10.3354/dao062045

Normal rainbow trout serum (RTS)-resistant variants of the infectious pancreatic necrosis virus (IPNV)-Jasper differ with respect to inhibition by RTS, serotype and cDNA sequence*

K. C. Park1,3,**, S.-J. Lee2, P. W. Reno1

1Department of Microbiology and Coastal Oregon Marine Experimental Station, Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Drive, Newport, Oregon 97365, USA
2Human Metabolism Section, Lab of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, 111 Alexander Drive, MD C3-01, PO Box 12233, Research Triangle Park,North Carolina 27709, USA
3Present address: Institute for Marine Biosciences, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, Canada
*The nucleotide sequences reported in this paper have been deposited in the GenBank data base (Accession No: AF399925 for Ja-S and AF399926 for Ja-R). **Email:

ABSTRACT: In order to determine if the infectious pancreatic necrosis virus isolate IPNV-Jasper (Ja-ATCC) is homogeneous or heterogeneous with respect to inhibition by normal rainbow trout serum (RTS), 50 clones were tested for sensitivity to RTS. The initial isolate was very sensitive to RTS, losing from 104 to 108 50% tissue culture infection dose (TCID50) ml–1 with a 1:100 dilution of RTS. The sensitivity of the clones ranged from highly sensitive to completely resistant (0 to 108 TCID50 ml–1 reduction). Eight percent of clones (4/50) were very sensitive to RTS (Ja-S) and 84% of clones (42/50) showed a mid-range of sensitivity to RTS. The final 8% of clones (4/50) were resistant to RTS (Ja-R). Enzyme immunodot assay revealed that Ja-S clones showed a monoclonal reaction identical to the parents, Ja-ATCC; however, Ja-R clones differed by several epitopes from the parental strain. Analysis of Ja-S and Ja-R revealed that there were significant differences in their nucleic acid sequences for the capsid protein VP2. These 2 strains shared 80.7 and 86.5% identity in nucleic acid and in amino acid sequences, respectively. Ja-S had 99.7 and 91.0% identity in nucleic acid sequences, and 99.5 and 95.9% in amino acid sequences with Ja-ATCC and Jasper-Dobos (Ja-D), respectively, while Ja-R showed 80.6 and 79.8% identity in nucleic acid sequences and 86.5 and 87.0% in amino acid sequences with Ja-ATCC and Ja-D, respectively. In conclusion, the Ja-ATCC population was heterogeneous in terms of RTS sensitivity, serotype and cDNA sequences from the VP2 coding region.

KEY WORDS: IPNV-Jasper variants · RTS inhibition · Serotype · cDNA sequence

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