[Show abstract][Hide abstract] ABSTRACT: We report the first full-length infectious clone of strain JX/CHA/97 of rabbit hemorrhagic disease virus (RHDV). The transcripts from the full-length cDNA clones were infectious when they were directly injected into rabbits. The sequence of the virus recovered from the rabbits was identical to that of the injected RNA transcripts. The cDNA clone was engineered to contain one silent nucleotide change to create an EcoRV site (A to T at nucleotide 2908). The genetic marker was retained in the recovered progeny virus. The transfection of RNA transcripts into RK-13 cells resulted in the synthesis of viral antigens, indicating that the cDNA clones were replication competent. This stable infectious molecular clone should be an important tool for developing a better understanding of the molecular biology and pathogenesis of RHDV.
Journal of Virology 08/2006; 80(13):6597-602. DOI:10.1128/JVI.02078-05 · 4.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Based on the infectious full-length cDNA clone of rabbit hemorrhagic disease virus (RHDV), the in vitro transcripts are introduced into RK13 cells. 12 h later, CPE could be observed clearly, and virual antigen could also be detected
by IFA. The titre of the recovered virus is 104.6/mL. Immune electron microscopic observation of the virus particles revealed that the particles were rotund with a diameter
of about 30 nm. Besides, virus titre quantification obtained by qRT-PCR showed a correlation between time from infection and
virus titre. All these results showed that we have recovered RHDV from RK13 cells by reverse genetics technology successfully,
and this would be very useful in studies of the antigenicity, virulence, pathogenesis, maturation and new type vaccines of
Chinese Science Bulletin 06/2006; 51(14):1698-1702. DOI:10.1007/s11434-006-2044-x · 1.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Previously, we demonstrated that a fusion protein (Gal-FMDV) consisting of beta-galactosidase and an immunogenic peptide, amino acids (141-160)-(21-40)-(141-160), of foot-and-mouth disease virus (FMDV) VP1 protein induced protective immune responses in guinea pigs and swine. We now designed a new potential recombinant protein vaccine against FMDV in swine. The immunogenic peptide, amino acids (141-160)-(21-40)-(141-160) from the VP1 protein of serotype O FMDV, was fused to the carboxy terminus of a swine immunoglobulin G single heavy chain constant region and expressed in Escherichia coli. The expressed fusion protein (IgG-FMDV) was purified and emulsified with oil adjuvant. Vaccination twice at an interval of 3 weeks with the emulsified IgG-FMDV fusion protein induced an FMDV-specific spleen proliferative T-cell response in guinea pigs and elicited high levels of neutralizing antibody in guinea pigs and swine. All of the immunized animals were efficiently protected against FMDV challenge. There was no significant difference between IgG-FMDV and Gal-FMDV in eliciting immunity after vaccination twice in swine. However, when evaluating the efficacy of a single inoculation of the fusion proteins, we found that IgG-FMDV could elicit a protective immune response in swine, while Gal-FMDV only elicited a weak neutralizing activity and could not protect the swine against FMDV challenge. Our results suggest that the IgG-FMDV fusion protein is a promising vaccine candidate for FMD in swine.
[Show abstract][Hide abstract] ABSTRACT: RNA interference (RNAi) is a powerful tool to silence gene expression posttranscriptionally. In this study, we evaluated the antiviral potential of small interfering RNA (siRNA) targeting VP1 of foot-and-mouth disease virus (FMDV), which is essential during the life cycle of the virus and plays a key role in virus attachment to susceptible cells. We investigated in vivo the inhibitory effect of VP1-specific siRNAs on FMDV replication in BHK-21 cells and suckling mice, a commonly used small animal model. The results showed that transfection of siRNA-expressing plasmids gave an 80 to 90% reduction in the expression of FMDV VP1 in BHK-21 cells. Moreover, BHK-21 cells transiently transfected with siRNA-expressing plasmids were specifically resistant to FMDV infection when exposed to 100 50% tissue culture infective doses of virus, and the antiviral effects extended to almost 48 h postinfection. Furthermore, subcutaneous injection of siRNA-expressing plasmids in the neck made suckling mice significantly less susceptible to FMDV. In conclusion, our data suggests that RNAi may provide a viable therapeutic approach to treat FMDV infection.
Journal of Virology 08/2004; 78(13):6900-7. DOI:10.1128/JVI.78.13.6900-6907.2004 · 4.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study, we provide evidence that a recombinant fusion protein containing beta-galactosidase and a tandem repeat peptide of immunogenic dominant epitope of foot-and-mouth disease virus (FMDV) VP1 protein elicits high levels of neutralizing antibody and protects both guinea pigs and swine against infection. Vaccination with this fusion protein induced a FMDV-specific proliferative T-cell response and a neutralizing antibody response. The immunized guinea pigs and swine were protected against FMD type O virus infection. Two DNA plasmids expressing genes of foot-and-mouth disease were constructed. Both plasmids pBO1 and pCO1 contain a signal sequence of the swine immunoglobulin G (IgG) gene and fusion protein gene of pXZ84. The signal sequence and fusion protein gene were under the control of a metallothionein promoter in the case of the pBO1 plasmid and under the control of a cytomegalovirus immediate early promoter in the case of pCO1 plasmid. When pBO1 and pCO1 were inoculated intramuscularly into guinea pigs, both plasmids elicited a neutralizing antibody response and spleen cell proliferation increased following stimulation with FMDV antigen, but animals were not protected from viral challenge.