Molecular cloning and expression in Escherichia coli of the glycoprotein gene of VHS virus, and immunization of rainbow trout with the recombinant protein.

Abstract

The gene encoding the envelope glycoprotein of a recent Danish isolate of a salmonid rhabdovirus, viral haemorrhagic septicaemia virus (VHSV) has been cloned and sequenced at the cDNA level. When compared with the deduced sequence of a French isolate of VHSV, it was noted that there were 13 amino acid substitutions in the Danish virus. Amino acid homologies with the glycoprotein of a North American salmonid rhabdovirus (infectious haematopoietic necrosis virus) indicate a high degree of structural similarity between the two fish rhabdovirus glycoproteins. Results from partial enzymatic deglycosylation of the viral protein indicate that all four NXT/S sites found in the sequence are N-glycosylated in the virus. The glycoprotein, without the N-terminal leader sequence and C-terminal hydrophobic anchor segment, was expressed in Escherichia coli as a factor Xa protease-cleavable fusion protein. The purified and renatured viral part of the recombinant protein was able to elicit VHSV-specific antibodies and neutralizing antibody activity in serum when injected into rainbow trout.