Construction of reverse genetic platform of highly pathogenic porcine reproductive and respiratory syndrome virus strain JXA1

Objective  To provide a basis for studying the structural function and pathogenic mechanism of highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV).

Method  Fragments of the whole genome of HP-PRRSV JXA1 strain were cloned into the modified low copy vector pOKq with reverse genetics technique. The CMV promoter and BGH termination signal peptide were added into the terminals of the viral genome. The FseI restriction site, as a genetic marker locus, was introduced at the 510th nucleotide of the whole genome of the virus by mutation. DNA-launched approach was used for viral rescue and the biological properties of rescued viruses were analyzed.

Result  The full-length cDNA clone of the constructed PRRSV JXA1 strain was infectious. The virus was successfully rescued and named rJXA1. The genetic marker was successfully introduced into the rescued virus. The rescued virus and parental virus had similar growth curves with reaching the maximum titer at 72 h after infection.

Conclusion  The reverse genetic platform of the JXA1 strain has been successfully constructed, which will lay a foundation for further research on the pathogenesis, gene function and vaccine development of PRRSV.