Rescue of Two Recombinant Canine Distemper Viruses That Separately Express Dabie Bandavirus Gn and Gc in Vitro

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne zoonosis with a high mortality rate in humans. Additionally, dogs are frequently reported to be infected with this disease. There has been no commercially available vaccine for humans and animals as yet. The SFTS is caused by Dabie bandavirus (DBV), formerly known as SFTS virus. The DBV is now classified into the genus Bandavirus in the family Phenuiviridae. DBV Gn and Gc can induce specific immune responses in vivo. In this study, we used reverse genetics to construct two recombinant canine distemper viruses (rCDV), rCDV-Gn and -Gc, which could express Dabie bandavirus Gn and Gc in vitro, respectively. Two foreign sequences, Gn and Gc open reading frames, were genetically stable during twenty serial viral passages in cells. Growth curve of the rCDV-Gc basically coincided with that of a wild-type CDV, but showed a significant difference from that of the rCDV-Gn. The rCDV-Gn and -Gc were derived from a common parental CDV, the virulence-attenuating QN strain. Therefore, if proven to be efficient in resisting both canine distemper and SFTS in dogs, either or both recombinant CDVs would be potential vaccine candidates.