University thesis:
Dissertation, Mathematisch-Naturwissenschaftliche Fakultät der Universität Greifswald, 2019
Footnote:
Literaturangaben
Text deutsch, Publikationen englisch, Zusammenfassungen in deutsch und englisch
Description:
Vakzine, DIVA Vakzine, KHV
Koi herpesvirus (KHV, Cyprinid herpesvirus 3) causes a fatal disease of koi and common carp. To obtain safe and efficacious live virus vaccines, we generated single and double deletion mutants of KHV lacking the genes encoding the nucleotide metabolism enzymes thymidine kinase (TK, ORF55) and deoxyuridine triphosphatase (DUT, ORF123). The mutations were introduced by homologous recombination in the cell culture adapted, but still virulent strain KHV-T. In vitro tests showed that deletion of the TK and DUT genes does not affect KHV replication in CCB cell cultures. In vivo tests using juvenile carp revealed that virulence of the single deletion mutants was significantly reduced compared to parental wild type virus, and that the double mutant was almost completely attenuated. Nevertheless, all immunized carp were protected against lethal challenge infections with virulent KHV. Using a novel triplex-real-time PCR and isolated DNA from gill swab samples, carp immunized with TK-deleted KHV could be differentiated from wild-type infected fish. Therefore, the double mutant KHV-TΔDUT/TK might be suitable as a genetic marker vaccine. In a second study the functions of four immunogenic envelope glycoproteins, encoded by the ORF25 gene family (ORF25, ORF65, ORF148, and ORF149) of KHV. It was observed that the four genes are not essential for in vitro virus replication. Whereas deletion of ORF65 did not detectably affect replication, deletion of ORF148 even slightly enhanced virus ...