Jui-Hung Shien

Goose parvovirus (GPV) and Muscovy duck parvovirus (MDPV) are the main agents associated with waterfowl parvovirus infections that caused great economic losses in the waterfowl industry. In 2020, a recombinant waterfowl parvovirus, 20-0910G, was isolated in a goose flock in Taiwan that experienced high morbidity and mortality. The whole genome of 20-0910G was sequenced to investigate the genomic characteristics of this isolate. Recombination analysis revealed that, like Chinese rMDPVs, 20-0910G had a classical MDPV genomic backbone and underwent two recombination events with classical GPVs at the P9 promoter and partial VP3 gene regions. Phylogenetic analysis of the genomic sequence found that this goose-origin parvovirus was highly similar to the circulating recombinant MDPVs (rMDPVs) isolated from duck flocks in China. The results of experimental challenge tests showed that 20-0910G caused 100% mortality in goose embryos and in 1-day-old goslings by 11 and 12 days post-inoculation, respectively. Taken together, the results indicated that this goose-origin rMDPV was closely related to the duck-origin rMDPVs and was highly pathogenic to young geese.

Chicken infectious anemia (CIA) is a poultry disease that causes huge economic losses in the poultry industry worldwide. Commercially available CIA vaccines are derived from wild-type chicken anemia viruses (CAVs) by serial passage in cells or chicken embryos. However, these vaccinal viruses are not completely attenuated; therefore, they can be transmitted vertically and horizontally, and may induce clinical symptoms in young birds. In this study, we sought to eliminate these issues by developing a subunit vaccine exploiting the CAV structural proteins, engineering recombinant baculovirus-infected Spodoptera frugiperda (Sf9) cells that contained both the viral protein 1 (VP1) and VP2 of CAV. Moreover, we produced single-chain chicken interleukin-12 (chIL-12) in the same system, to serve as an adjuvant. The recombinant VP1 was recognized by chicken anti-CAV polyclonal antibodies in Western blotting and immunofluorescence assays, and the bioactivity of the recombinant chIL-12 was confirmed by stimulating interferon-γ (IFN-γ) secretion in chicken splenocytes. Furthermore, the ability of the recombinant VP1 to generate self-assembling virus-like particles (VLPs) was confirmed by transmission electron microscopy. Specific pathogen-free (SPF) chickens inoculated with VLPs and co-administered the recombinant chIL-12 induced high CAV-specific antibodies and cell-mediated immunity. Taken together, the VLPs produced by the baculovirus expression system have the potential to be a safe and effective CIA vaccine. Finally, we demonstrated the utility of recombinant chIL-12 as an adjuvant for poultry vaccine development.

Purpose: Liver cancer is the second most common cause of death worldwide. This study was to investigate the SPECT/CT, ultrasound, biodistribution and therapeutic evaluation of ¹⁸⁸Re-human serum albumin microspheres (¹⁸⁸Re-HSAM) in the GP7TB orthotopic hepatoma rat model. Materials and methods: HSAM was labeled with ¹⁸⁸Re by using a home-made kit and microwave system. The ¹⁸⁸Re-HSAM was administered via intraarterial route. The in vivo distribution of ¹⁸⁸Re-HSAM was determined by biodistribution analysis and nanoSPECT/CT system. In efficacy, tumor volumes were tracked longitudinally by three-dimensional ultrasound. Results: The biodistribution and nanoSPECT/CT imaging showed that ¹⁸⁸Re-HSAM could accumulate in liver and tumor. The correlation coefficient of tumor volumes done by three-dimensional ultrasound and at autopsy was 0.997. In efficacy, tumor volume in the normal saline-treated group was 1803.2 mm³ at 54 days after tumor inoculation. Tumor volumes in the 103.6 MBq and 240.5 MBq of ¹⁸⁸Re-HSAM treated groups were 381 and 267.4 mm³ (p = 0.001 and 0.004), respectively. Conclusions: These results show that three-dimensional ultrasound with a high spatial resolution and contrast in soft tissue can become imaging modality in assessing tumor burden and tumor progression in an orthotopic rat model. The longitudinally therapeutic evaluation of ¹⁸⁸Re-HSAM demonstrated dose-dependent tumor growth inhibition with increased dose in the GP7TB orthotopic hepatoma rat model.

The sequence at the hemagglutinin (HA) cleavage site (CS) plays a key role in determining the pathogenicity of avian influenza viruses. Three types of HA CS sequences, QREKR/GL, QRKKR/GL and QRRKR/GL, were previously reported in Taiwanese H5N2 viruses that were isolated from chickens from 2003 to 2013. However, no HA CS sequence was reported for viruses isolated after 2013. This article presents the HA CS sequences and pathogenicity of H5N2 viruses that were isolated from chickens in Taiwan during 2013-2015. Two novel HA CS sequences, QKEKR/GL and KREKREKR/GL, were found in the viruses isolated in 2013 and 2014, and pathogenicity tests showed that the viruses with these novel HA CS sequences are low and high pathogenic viruses, respectively. In contrast, the HA CS sequence QREKR/GL was found in all viruses that were isolated in 2015, and all of these viruses were low pathogenic viruses. After 10 passages in embryonated chicken eggs, a virus strain that was isolated in 2003 evolved into a viral quasispecies that contained at least four distinct types of HA CS sequences. These results highlight the potential of Taiwanese H5N2 viruses to change their pathogenicity and HA CS sequences via mutations. Furthermore, viruses with the HA CS sequence QREKR/GL were more prevalent than others in 2015. These findings are useful for understanding the mechanism of sequence changes at the HA CS and for refining H5N2 virus control measures in Taiwan.

The spike (S) protein, containing two subunits, S1 and S2, is the major immunity-eliciting antigen of avian infectious bronchitis virus (IBV), a highly contagious disease of chickens. Several immunogenic regions, mainly located within the S1 subunit, have been identified. Nonetheless, these immune-dominant regions were defined using selected monoclonal antibodies or using a short peptide approach that involves only certain limited regions of the S protein. In addition, some immune-dominant regions are located in hypervariable regions (HVRs) which are not present in all serotypes. Hence, the aim of this study was to determine a broader range of antigenic regions that have strong antibody eliciting ability; these could then be applied for development of an IBV-diagnostic tool. Initially, the S1 and part of the S2 subunit protein (24–567 amino acids) were expressed as five fragments in prokaryotic system. The antigenicity was confirmed using IBV immunized sera. Performance of the S subfragments was evaluated by ELISA using a panel of field chicken sera with known IBV titres determined by a commercial kit. This indicated that, among the five antigenic recombinant proteins, the region S-E showed the highest specificity and sensitivity, namely 95.38 % and 96.29 %, respectively. The κ value for the in-house ELISA using the S-E fragment compared to a commercial kit was 0.9172, indicating a high agreement between these two methods. As region S-E harbors strong immunogenicity within the spike protein, it has the potential to be exploited as an antigen when developing a cost-effective ELISA-based diagnosis tool.