Pseudorabies is an economically important disease in a variety ot animals caused by pseudorabies virus. Since 2011, pseudorabies outbreaks occurred in many regions of China. Related researches on this virus become a hot topic in virology and veterinary. One of the difficulties for pseudorabies prevention and control is innate immune evasion. Explorations on this issue are conducive to the development of vaccine and drugs. Therefore, this review summarized the recent research progress on the mechanisms of pseudorabies virus innate immune evasion. Theoretical direction was provided on effetive prevention and control of pseudorabies owing to this review.
Animals ; Herpesvirus 1, Suid ; genetics ; immunology ; Humans ; Immune Evasion ; Immunity, Innate ; Pseudorabies ; immunology ; virology

With the application of gE gene deleted pseudarabies virus (PRV) vaccine worldwide, a corresponding differential diagnosis based on gE glycoprotein is needed in the project of PRV eradication. In this study, PRV gE gene without signal and transmembrane region was amplified by PCR and cloned into pGEX-6P-1, generated pGEX-gE. After transformation of BL21 with pGEX-gE, an expressed fusion protein(about 63kD) was identified by SDS-PAGE. The recombinant proteins are produced as inclusion bodies. By changing the inductive conditions, the formation of inclusion bodies was inhibited and tended to increase the percentage of soluble recombinant protein. The antigenic reactivity of the recombinant protein was confirmed by Western blotting with polyclonal antibodies against PRV. Using purified recombinant tgE as antigen, an ELISA was developed to detect sera of PRV infected pigs and sera of pigs immunized with gE-deleted PRV vaccine. The total of 400 serum samples collected from field were comparatively tested with the tgE-ELISA and a commercial competitive ELISA based on monoclonal antibody against gE, the results indicated that the coincidental rate between the two tests is about 94%.
Animals ; Diagnosis, Differential ; Enzyme-Linked Immunosorbent Assay ; Herpesvirus 1, Suid ; immunology ; Pseudorabies ; diagnosis ; Pseudorabies Vaccines ; immunology ; Recombinant Proteins ; biosynthesis ; immunology ; Swine ; Vaccination ; Viral Envelope Proteins ; genetics ; immunology

The hippocampus is a central area of the memory-related neural system. Combined immunohistochemistry against choline acetyl transferase and retrograde transneuronal labelling of the pseudorabies virus were used to identify cholinergic neurons in the central nervous system projecting to the hippocampal formation of the rat. Five to ten microL of Bartha strain of pseudorabies virus were injected into the dentate gyrus, CA1 and CA3 of the hippocampus of 20 Sprague Dawley rats using stereotaxic instrument. Forty eight to 96 hr after the injection, the brains were removed and the tissue sections were processed for double immunofluorescence procedure using polyclonal antibodies against pseudorabies virus or choline acetyl transferase. The double labelled neurons were distributed at several different nuclei and the labelling patterns of three different areas of the hippocampus were similar. These data suggests that the cholinergic innervation to the hippocampus were distributed in a transsynaptic manner throughout the whole brain area.
Animal ; Antibodies ; Choline O-Acetyltransferase/*analysis/immunology ; Cholinergic Fibers/*enzymology ; Herpesvirus 1, Suid/immunology ; Hippocampus/*cytology ; Immunohistochemistry ; Microinjections ; Neural Pathways ; Rats ; Rats, Sprague-Dawley

To construct a TK-/gG- mutant of pseudorabies virus, the gG-detected transfer vector pUSKKBB and genomic DNA of pseudorabies virus TK-/gG-/LacZ+ were co-transfected into IBRS-2 cells. Transfection progeny were plated onto PK-15 cells and incubated for 2 days under methylcellulose. Then the overlay was removed and replaced by 1% low melting point agarose in DMEM supplemented with 150 microg/mL X-gal. After 2 days, white plaques were screened for and purified 4 times. By PCR amplification of gG-deleted gene and LacZ gene, a recombinant virus with TK-/gG- phenotype was confirmed. Sequence of the PCR product revealed that there were 1,176 bp detection in gG gene of the PRV TK-/gG- mutant. Amplifying the gG-deleted gene of different generations of the TK-/gG- mutant showed that the mutant was stable within PK-15 cells. TCID50 assay indicated that the recombinant virus grows well on PK-15 cells. The mice immunized with the TK-/gG- virus showed no sign of abnormality. As a control, all mice inoculated with PRV strain died from the infection. All mice that received TK-/gG- survived after a lethal PRV challenge. However none of the mice injected with phosphate-buffer saline (PBS) survived from the challenge. The above results demonstrated that the recombinant virus could be a candidate marker vaccine strain for eradicating pseudorabies in pig herds.
Animals ; Herpesvirus 1, Suid ; genetics ; pathogenicity ; Mice ; Mice, Inbred BALB C ; Mutation ; Pseudorabies Vaccines ; immunology ; Swine ; Thymidine Kinase ; genetics ; Vaccines, Synthetic ; Viral Envelope Proteins ; genetics ; immunology

We designed two pairs of primers and their corresponding TaqMan probes according to gH, gE gene of PRV. By optimizing the probe's concentration, Mg2+ concentration, primers concentration and sample DNA extraction, real-time fluorescent quantitative PCR (FQ-PCR) which can quickly identity field virus and vaccine virus of PRV was established. According to our results, the dynamic range of the FQ-PCR assay is between 10 x 10(1) copies/microL and 10 x l0(8) copies/microL, and the detection limit of FQ-PCR is 1.0 x 10(1) copies/microL, which is 100 fold higher than that of conventional PCR. We detected 60 doubtful tissue samples using the FQ-PCR assay, serum neutralization and conventional PCR. In conclusion, the FQ-PCR method is rapid, sensitive, specific and accurate, and can be used to detect field strains of PRV rapidly. The closed-tube format of the assay minimized the risk of contamination of subsequent reaction and the assay can be performed in 2 h or less. Development of real-time quantitative PCR provides the basis for the early and rapid detection and analyzing quantitatively the infectious degree of PRV.
Animals ; Fluorescent Dyes ; Herpesvirus 1, Suid ; genetics ; isolation & purification ; Polymerase Chain Reaction ; methods ; Pseudorabies ; diagnosis ; prevention & control ; virology ; Pseudorabies Vaccines ; immunology ; isolation & purification ; Swine

Pseudorabies virus (PRV), an alpha-herpesvirus, has been used as a vector for live-viral animal vaccines. The recombinant PRV TK- / gE- / GP5+, which expressing GP5 of PRRSV, is developed based on the PRV genetic-depleting vaccine-virus strain, TK- / gE- /LacZ+. However, this strain stimulated poorly the vaccinated animals to produce neutralizing antibodies against PRRSV. In order to develop a booster specific immunized response of the PRV recombinant, the ORF5 gene of PRRSV TK- / gE- / LacZ+ was substituted by a modified ORF5 gene, ORF5m. The resultant recombinant PRV, TK- /gE- / GP5m+, was verified by PCR, Southern blotting and Western blotting. TK- / gE- / GP5m+ and TK- / gE- / GP5+ expressed GP5 proteins were inoculated into balb/c mice to evaluate their immunogenicity. The results demonstrated that the amount of neutralization antibodies and cell-immunity responses induced by TK- / gE- /GP5m+ against PRRSV were higher than that of TK- / gE- / GP5+. This study indicated that the new recombinant PRV expressing the modified GP5m protein is a candidate for the development of bivalent genetic engineering vaccines against PRRSV and PRV.
Animals ; Genetic Vectors ; Herpesvirus 1, Suid ; genetics ; immunology ; Mice ; Mice, Inbred BALB C ; Porcine respiratory and reproductive syndrome virus ; genetics ; immunology ; Recombinant Fusion Proteins ; genetics ; immunology ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Swine ; Viral Envelope Proteins ; biosynthesis ; genetics ; Viral Vaccines ; genetics ; immunology

Pseudorabies virus (PRV), a veterinary pathogen that infects domestic animals as well as wild animals such as wild boar and feral swine, was recently reported to infect human and led to endophthalmitis and encephalitis. A retrospective seroepidemiologic survey was conducted using 1,335 serum samples collected from patients with encephalitis and ELISA positive rates were 12.16%, 14.25%, and 6.52% in 2012, 2013, and 2017, respectively. The virus neutralizing antibody titers of positive samples correlated well with ELISA results. The pseudorabies virus antibody positive rate of patients with encephalitis were higher than that of healthy people in 2017. The above results suggest that some undefined human encephalitis cases may be caused by PRV infection.
Adult ; Animals ; Antibodies, Viral ; blood ; China ; Encephalitis ; immunology ; virology ; Enzyme-Linked Immunosorbent Assay ; Female ; Herpesvirus 1, Suid ; immunology ; Humans ; Male ; Middle Aged ; Prevalence ; Pseudorabies ; blood ; immunology ; virology ; Retrospective Studies ; Seroepidemiologic Studies ; Young Adult

Replication-incompetent adenoviruses expressing three major glycoproteins (gB, gC, and gD) of pseudorabies virus (PrV) were constructed and used to examine the ability of these glycoproteins to induce protective immunity against a lethal challenge. Among three constructs, recombinant adenovirus expressing gB (rAd-gB) was found to induce the most potent immunity biased to Th1-type, as determined by the IgG isotype ratio and the profile of the Th1/Th2 cytokine production. Conversely, the gC-expressing adenovirus (rAd-gC) revealed Th2-type immunity and the gD-expressing adenovirus (rAd-gD) induced lower levels of IFN-gamma and IL-4 production than other constructs, except IL-2 production. Mucosal delivery of rAd-gB induced mucosal IgA and serum IgG responses and biased toward Th2-type immune responses. However, these effects were not observed in response to systemic delivery of rAd-gB. In addition, rAd-gB appeared to induce effective protective immunity against a virulent viral infection, regardless of whether it was administered via the muscular or systemic route. These results suggest that administration of replication-incompetent adenoviruses can induce different types of immunity depending on the expressed antigen and that recombinant adenoviruses expressing gB induced the most potent Th1-biased humoral and cellular immunity and provided effective protection against PrV infection.
Adenoviridae/genetics/*immunology/metabolism ; Animals ; Antibody Formation ; Cell Line ; Cytokines/immunology ; Female ; Glycoproteins/biosynthesis/genetics/*immunology ; Herpesvirus 1, Suid/genetics/*immunology/physiology ; Immunity, Cellular ; Immunoglobulin G/immunology ; Mice ; Mice, Inbred C57BL ; Pseudorabies/*immunology/prevention & control ; Pseudorabies Vaccines/administration & dosage/*immunology ; Swine ; Th1 Cells/immunology ; Th2 Cells/immunology ; *Virus Replication

We studied the immunogenicity of pseudorabies virus gC DNA vaccination by fusing the murine complement C3d receptor binding domain. First, pseudorabies virus gC gene was linked to four copies of C3d receptor binding domain (M284), and then cloned into the vector pcDNA3.1 to construct the recombinant plasmid sgC-M284. Through the experiment of immunized BALB/c mice, we found that the enzyme linked immunosorbent assay (ELISA) antibody titer for sgC-M284 was 17-fold higher than that for sgC alone, and protective rate of mice was augmented from 25% to 88% after lethal dose PrV (316 LD50) challenge. In addition, the IL-4 levels for sgC-M284 immunization approached that for the pseudorabies virus inactivated vaccine. In conclusion, we demonstrated murine C3d receptor binding domain fusion significantly increased Th2-biased immune response by inducing IL-4 production.
Adjuvants, Immunologic ; physiology ; Animals ; Antibody Formation ; immunology ; Binding Sites ; Cloning, Molecular ; Complement C3d ; genetics ; immunology ; Herpesvirus 1, Suid ; genetics ; immunology ; Interleukin-4 ; immunology ; Mice ; Mice, Inbred BALB C ; Pseudorabies Vaccines ; immunology ; Receptors, Complement 3d ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Swine ; Vaccines, DNA ; immunology ; Viral Envelope Proteins ; pharmacology ; Viral Fusion Proteins ; immunology

In order to develop a combined live vaccine that will be used to prevent against porcine parvovirus (PPV) and Pseudorabies virus (PRV) infection, the VP2 gene of PPV was inserted into the transfer vector plasmid pG to produce the recombinant plasmid pGVP2. The plasmid pGVP2 and the genome of PRV HB98 attenuated vaccine were transfected by using lipofectamine into swine testis cells for the homologous recombination. The recombinant virus rPRV-VP2 was purified by selection of green fluorescence plaques for five cycles. 6-week-old female Kunming mice were immunized intramuscularly with attenuated PRV parent HB98 strain, commercial inactivated vaccine against PPV, recombinant virus, DMEM culture solution. The injections were repeated with an equivalent dose after 2 weeks in all of the groups, and then challenged with the virulent PRV NY strain at 7 weeks after the first immunization. The recombinant virus rPRV-VP2 was successfully generated, and the recombinant virus could effectively elicite anti-PPV and PRV antibody and significant cellular immune response as indicated by anti-PPV ELISA and HI, PRV-neutralizing assay and flow cytometry. The challenge assay indicated that recombinant virus could protect the mice against the virulent PRV challenge. These results demonstrated that the recombinant virus can be a candidate recombinant vaccine strain for the prevention of PRV and PPV.
Animals ; Antibodies, Viral ; immunology ; Antigens, Viral ; administration & dosage ; genetics ; immunology ; Capsid Proteins ; administration & dosage ; genetics ; immunology ; Female ; Gene Expression ; Genetic Vectors ; genetics ; metabolism ; Herpesvirus 1, Suid ; genetics ; metabolism ; Mice ; Parvovirus, Porcine ; genetics ; immunology ; Swine ; Swine Diseases ; immunology ; prevention & control ; virology ; Viral Vaccines ; administration & dosage ; genetics ; immunology