| Mutant Z-19 has been isolated from Friend erythroleukemia cells persistently infected with vaccinia virus and characterized. It had 20-21 kb deletion at the left end, including HindIII C and part of HindIII N fragments, and rearrangements at the right end of viral N genome. Since mutant Z-29 provides a null virulence background, it is a good model system to study pathogenicity. Furthermore, it was previously reported that in Jurkat cells persistently infected with vaccinia virus, there is stimulation of cytokine synthesis (IL-2, IL-2 receptor-a, and IL-6) and increase in the transactivation of HIV-1LTR transcription.;The aim of this thesis was to study the molecular pathogenicity of vaccinia virus and to investigate virus-host interaction in Jurkat cells persistently infected with vaccinia virus. Three aspects were explored. (1) To determine if the virulent phenotype can be recovered by introduction of the terminal HindIII C fragment into the attenuated mutant Z-19, rescue experiments were performed, and recombinant viruses were isolated and characterized. The results showed that recovery of virulence in mice was correlated with the presence and expression of two genes: vaccinia growth factor and vaccinia complement-binding protein, both located at the left terminus. (2) To establish a model system to identify which gene(s) is/are responsible for virulence in the IHD-W strain, a shuttle vector was constructed to reintroduce genes into the mutant Z-19. The shuttle vector contained the fusion fragment K... |
