Veterinary biotechnologies that represent the applications of biotechnologies in veterinary science are advancing rapidly in the last decade in spite of relatively late kickoff. This special issue consists of four sections, reviews, new technologies, new methods and others, presenting the recent progress in diagnostic assays, vaccines and others of emerging and reemerging animal infectious diseases.

Baculovirus-mediated gene transfer into mammalian cells has been used to develop non-replicative vector vaccines against a number of diseases in several animal models.A baculovirus pseudotyped with the glycoprotein of vesicular stomatitis virus was used as vector to construct the recombinant baculovirus expressing classical swine fever virus(CSFV) E2 protein under the control of ie1 promoter from white spot syndrome virus.The E2 gene was shown to be efficiently expressed in both insect and mammalian cells.Intramuscular injection of mice with the recombinant baculovirus resulted in the production of high-level CSFV-specific antibodies.Specific lymphoproliferative responses to the CSFV stimulation were induced in the splenocytes of the immunized mice as demonstrated by CFSE staining assay and WST-8 assay.The results indicates that the pseudotyped baculovirus-delivered gene can be a potential non-replicative vaccine against CSFV infection.

Classical swine fever (CSF), caused by classical swine fever virus (CSFV), has been epidemic or endemic in many countries, and causes great economical losses to pig industry worldwide. Attenuated vaccines (such as C-strain) have played an important role in the control of CSF. Recently some new phenomena appear, such as atypical and persistent infections of CSF, immunization failure and so on. Meanwhile, eradication programs have been implemented in many countries, restricting the widespread applications of attenuated vaccines. Thus, currently the priority is to strengthen the research in pathogenesis and transmission mechanisms, as well as to develop marker vaccines. Recently, the applications of reverse genetics technology open up a new way for research of structure and function of CSFV proteins and development of novel vaccines against CSF. This review focuses on the progress of applications of reverse genetics in the functional analysis and marker vaccine development of CSFV, and also discusses the problems confronted now and prospective aspects in the study of CSFV.
Classical swine fever virus ; genetics ; Cloning, Molecular ; Genetics, Microbial ; methods ; RNA, Viral ; genetics ; Recombination, Genetic ; Vaccines, Synthetic ; biosynthesis ; immunology ; Viral Vaccines ; biosynthesis ; genetics

In 1990, it was reported that the naked DNA encoding an antigen (so-called DNA vaccine) transduced directly into the muscle is able to induce immune responses just like antigen inoculation. Since then, a number of DNA vaccines against different diseases have been developed and shown to induce different levels of specific humoral and/or cell-mediated immunity. Efforts have been made to develop effective DNA vaccines against classical swine fever (CSF). This review covered the following aspects in the development and application of CSF DNA vaccines: construction and evaluation, application of adjuvants, combination with other vaccines and the existing problems and solutions.
Adjuvants, Immunologic ; pharmacology ; Animals ; Classical Swine Fever ; prevention & control ; Swine ; Vaccines, DNA ; biosynthesis ; immunology ; Viral Envelope Proteins ; genetics ; immunology ; Viral Vaccines ; biosynthesis ; immunology

Classical swine fever (CSF), an acute and highly contagious disease of swine, is caused by classical swine fever virus. CSF is one of the most devastating diseases to the pig industry worldwide and results in serious economic losses. Currently prophylactic vaccination is still an important strategy for the control of CSF. Live attenuated vaccines (such as C-strain) are safe and effective. However, there are significant changes in the clinical features of CSF, displaying concurrent typical and atypical CSF, and simultaneous inapparent and persistent infections. Immunization failure has been reported frequently and it is difficult to distinguish between wild-type infected and vaccinated animals (DIVA). So there is an urgent need to develop more effective and safer DIVA or marker vaccines for the control of CSF. In this review, some of the most recent advances in new-type vaccines against CSF, including DNA vaccines, live virus-vectored vaccines, protein or peptide-based vaccines, gene-deleted vaccines and chimeric pestivirus-based vaccines, are reviewed and discussed.
Animals ; Classical Swine Fever ; prevention & control ; Classical swine fever virus ; Swine ; Vaccination ; veterinary ; Vaccines, Attenuated ; immunology ; Vaccines, DNA ; immunology ; Vaccines, Subunit ; immunology ; Viral Vaccines ; immunology

We have previously evaluated a Semliki Forest virus (SFV) replicon vectored DNA vaccine (pSFV1CS2-E2) and a recombinant adenovirus (rAdV-E2) expressing the E2 glycoprotein of classical swine fever virus (CSFV) in pigs. The results showed that the immunized pigs were protected from virulent challenge, but few pigs showed short-term fever and occasional pathological changes following virulent challenge. To enhance the immunogenecity of the vaccines, we tried a prime-boost vaccination strategy using a combination of prime with pSFV1CS2-E2 followed by boost with rAdV-E2. The results showed that all the immunized pigs developed high-level CSFV-specific antibodies following prime-boost immunization. When challenged with virulent CSFV, the immunized pigs (n = 5) from the heterologous boost group showed no clinical symptoms, and CSFV RNA was not detected following challenge, whereas one of five pigs from the homologous boost group developed short-term fever and CSFV RNA was detected. This demonstrates that the heterologous prime-boost vaccination regime has the potential to prevent against virulent challenge.
Adenoviridae ; genetics ; metabolism ; Adenovirus E2 Proteins ; genetics ; immunology ; Animals ; Classical Swine Fever ; immunology ; prevention & control ; Classical swine fever virus ; genetics ; immunology ; Genetic Vectors ; Immunization, Secondary ; Replicon ; genetics ; Semliki forest virus ; genetics ; metabolism ; Swine ; Vaccines, DNA ; immunology ; Viral Envelope Proteins ; genetics ; metabolism ; Viral Vaccines ; immunology

To compare the activity of different promoter in baculovirus-insect system, a series of recombinant baculoviruses were generated harboring the E-GFP reporter gene under the control of one of 5 promoters, including the ie1 promoter of shrimp white spot syndrome virus (WSSV), the truncated ie1 (mie1) promoter, the ETL promoter of the baculovirus, the elongated ETL (mETL) promoter, and the polyhedron promoter (P(PH)) of the baculovirus. The expression efficiency of the E-GFP reporter gene in the recombinant baculovirus-infected Sf9 cells was determined by flow cytometry. The results showed that both ie1 and mETL promoters had a strong promoter activity at early phase, while P(PH) showed a strong promoter activity at late phase. The ie1 promoter suggested the strongest promoter activity. The homologous region 1 (hr1) was also found to enhance the ETL promoter activity.
Animals ; Baculoviridae ; genetics ; metabolism ; Green Fluorescent Proteins ; genetics ; metabolism ; Insecta ; genetics ; metabolism ; Penaeidae ; virology ; Promoter Regions, Genetic ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Transfection ; White spot syndrome virus 1 ; genetics

The aim of this study was to construct the complete genome of Marek's disease virus serotype 814 strain as an infectious bacterial artificial chromosome (BAC). Using self-designed selection marker Eco-gpt (1.3 kb) and BAC vector pBeloBAC11 (7.5 kb), we constructed the transfer plasmid pUAB-gpt-BAC11. The plasmid pUAB-gpt-BAC11 and MDV total-DNA were cotransfected into secondary CEFs; we put the virus-containing cells in selection medium for eight rounds and obtained purified recombinant viruses. Recombinant viral genomes were extracted and electroporated into E. coli, BAC clones were identified by restriction enzyme digestion and PCR analysis. Finally, we obtained 38 BAC clones, DNA from various MDV-1 BACs was transfected into CEFs, and recombinant virus was reconstituted by transfection of MDV-BAC2 DNA. We successfully cloned the complete genome of MDV-1814 strain as an infectious bacterial artificial chromosome. With these cloned genomes, a revolutionary MDV-DNA engineering platform utilizing RED/ET recombination system was constructed successfully, which can help the understanding of MDV gene functions and promote the using of MDV as a vector for expressing foreign genes. In addition, it opens the possibility to generate novel MDV-1 vaccines based on the BACs.
Animals ; Chickens ; immunology ; virology ; Chromosomes, Artificial, Bacterial ; genetics ; Cloning, Molecular ; DNA, Recombinant ; genetics ; DNA, Viral ; genetics ; Fibroblasts ; metabolism ; Genetic Engineering ; methods ; Mardivirus ; classification ; genetics ; physiology ; Serotyping ; Transfection ; Viral Proteins ; genetics ; physiology ; Virus Replication

In order to ensure the biosafety of the IFN-gamma antiviral activity assay, we used a replication-deficient VSV carrying GFP as an interferon sensitive indicator virus (VSVdeltaG*G). The antiviral activities of porcine IFN-gamma expressed in Escherichia coli and in baculovirus on MDBK cells were assessed. The results showed that the antiviral activity of porcine IFN-gamma expressed in baculovirus could reach 10(5) IU/mL, while the porcine IFN-gamma expressed in E. coli showed some antiviral activity (32 IU/mL) after refolding. The results of the VSVdeltaG*G-based antiviral assay were almost identical to that of the VSV*GFP-based assay, suggesting it is highly feasible to use VSVdeltaG*G as a substitute for VSV*GFP, making assays for IFN-gamma antiviral activity safer and more accurate.
Animals ; Antiviral Agents ; pharmacology ; Baculoviridae ; genetics ; metabolism ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Interferon-gamma ; biosynthesis ; genetics ; metabolism ; pharmacology ; Recombinant Proteins ; biosynthesis ; genetics ; pharmacology ; Swine ; Vesiculovirus ; drug effects ; physiology

Classical swine fever (CSF), which is caused by classical swine fever virus (CSFV), causes significant losses in pig industry in many countries in Asia and Europe. The E2 glycoprotein of CSFV is the main target for neutralizing antibodies. In this study, a recombinant replication-defective human adenovirus expressing the CSFV E2 gene (rAdV-E2) was generated and evaluated for the immunogenicity in rabbits. The results showed that the rabbits immunized with rAdV-E2 developed high-level CSFV-specific antibodies. The rAdV-E2-immunized rabbits were all free of the regular fever and the viral replication in the spleen upon challenge with C-strain, which were seen in the rabbits immunized with the parent adenovirus of rAdV-E2. This indicates that the recombinant adenovirus can be an attractive candidate vaccine against CSF.
Adenoviridae ; genetics ; immunology ; metabolism ; Animals ; Antibodies, Viral ; blood ; Genetic Vectors ; genetics ; Immunization ; Rabbits ; Random Allocation ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Transfection ; Viral Envelope Proteins ; biosynthesis ; genetics ; immunology ; Viral Vaccines ; immunology