Generation of a potential koi herpesvirus live vaccine by simultaneous deletion of the viral thymidine kinase and dUTPase genes
| Autor: | Sven Bergmann, Dirk Höper, Lars Schröder, Yeonhwa Jin, Walter Fuchs, Sandro Klafack, Thomas C. Mettenleiter, Pei-Yu Lee, Dieter Fichtner |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Carps Cyprinid herpesvirus 3 030106 microbiology ved/biology.organism_classification_rank.species Mutant Vaccines Attenuated Virus Replication Thymidine Kinase Virus Fish Diseases 03 medical and health sciences Common carp Virology Animals Israel Pyrophosphatases Carp Cells Cultured Herpesviridae Sequence Deletion Attenuated vaccine biology ved/biology Herpesviridae Infections biology.organism_classification 030104 developmental biology Viral replication Thymidine kinase DNA Viral |
| Zdroj: | Journal of General Virology. 100:642-655 |
| ISSN: | 1465-2099 0022-1317 |
| DOI: | 10.1099/jgv.0.001148 |
| Popis: | Koi herpesvirus (KHV, Cyprinidherpesvirus 3) causes a fatal disease of koi and common carp. To obtain safe and efficacious live vaccines, we generated deletion mutants of KHV lacking the nonessential genes encoding two enzymes of nucleotide metabolism, thymidine kinase (TK, ORF55) and deoxyuridine-triphosphatase (DUT, ORF123). Since single-deletion mutants based on a KHV isolate from Israel (KHV-I) only exhibited partial attenuation (Fuchs W, Fichtner D, Bergmann SM, Mettenleiter TC. Arch Virol 2011;156 : 1059–1063), a corresponding double mutant was generated and tested in vivo, and shown to be almost avirulent but still protective. To overcome the low in vitro virus titres of KHV-I (≤105 p.f.u. ml−1), single and double TK and DUT deletions were also introduced into a cell culture-adapted KHV strain from Taiwan (KHV-T). The deletions did not affect in vitro virus replication, and all KHV-T mutants exhibited wild-type-like plaque sizes and titres exceeding 107 p.f.u. ml−1, as a prerequisite for economic vaccine production. Compared to wild-type and revertant viruses, the single-deletion mutants of KHV-T were significantly attenuated in vivo, and immersion of juvenile carp in water containing high doses of the double mutant caused almost no fatalities. Nevertheless, the deletion mutants induced similar levels of KHV-specific serum antibodies to the parental wild-type virus, and conferred solid protection against disease after challenge with wild-type KHV. For the convenient differentiation of DNA samples prepared from gill swabs of carp infected with wild-type and TK-deleted KHV we developed a triplex real-time PCR. Thus, KHV-TΔDUT/TK might be suitable as a genetic DIVA vaccine in the field. |
| Databáze: | OpenAIRE |
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