Yeast ß-glucan promotes antiviral type I interferon response via dectin-1.

Pseudorabies virus (PRV), an alphaherpesvirus, is a neglected zoonotic pathogen. Dectin-1 sensing of ß-glucan (BG) induces trained immunity, which can possibly form a new strategy for the prevention of viral infection. However, alphaherpesvirus including PRV have received little to no investigation in the context of trained immunity. Here, we found that BG pretreatment improved the survival rate, weight loss outcomes, alleviated histological injury and decreased PRV copy number of tissues in PRV-infected mice. Type I interferons (IFNs) including IFN-α/ß levels in serum were significantly increased by BG. However, these effects were abrogated in the presence of Dectin-1 antagonist. Dectin-1-mediated effect of BG was also confirmed in porcine and murine macrophages. These results suggested that BG have effects on type I IFNs with antiviral property involved in Dectin-1. In piglets, oral or injected immunization with BG and PRV vaccine could significantly elevated the level of PRV-specific IgG and type I IFNs. And it also increased the antibody levels of porcine reproductive and respiratory syndrome virus vaccine and classical swine fever vaccine that were later immunized, indicating a broad-spectrum effect on improving vaccine immunity. On the premise that the cost was greatly reducing, the immunological effect of oral was better than injection administration. Our findings highlighted that BG induced type I IFNs related antiviral effect against PRV involved in Dectin-1 and potential application value as a feed additive to help control the spread of PRV and future emerging viruses.

The 25-kDa linear polyethylenimine exerts specific antiviral activity against pseudorabies virus through interferencing its adsorption via electrostatic interaction.

Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease, which is responsible for enormous economic losses to the global pig industry. Although vaccination has been used to prevent PRV infection, the effectiveness of vaccines has been greatly diminished with the emergence of PRV variants. Therefore, there is an urgent need to develop anti-PRV drugs. Polyethylenimine (PEI) is a cationic polymer and has a wide range of antibacterial and antiviral activities. This study found that a low dose of 1 µg/mL of the 25-kDa linear PEI had significantly specific anti-PRV activity, which became more intense with increasing concentrations. Mechanistic studies revealed that the viral adsorption stage was the major target of PEI without affecting viral entry, replication stages, and direct inactivation effects. Subsequently, we found that cationic polymers PEI and Polybrene interfered with the interaction between viral proteins and cell surface receptors through electrostatic interaction to exert the antiviral function. In conclusion, cationic polymers such as PEI can be a category of options for defense against PRV. Understanding the anti-PRV mechanism also deepens host-virus interactions and reveals new drug targets for anti-PRV.IMPORTANCEPolyethylenimine (PEI) is a cationic polymer that plays an essential role in the host immune response against microbial infections. However, the specific mechanisms of PEI in interfering with pseudorabies virus (PRV) infection remain unclear. Here, we found that 25-kDa linear PEI exerted mechanisms of antiviral activity and the target of its antiviral activity was mainly in the viral adsorption stage. Correspondingly, the study demonstrated that PEI interfered with the virus adsorption stage by electrostatic adsorption. In addition, we found that cationic polymers are a promising novel agent for controlling PRV, and its antiviral mechanism may provide a strategy for the development of antiviral drugs.

A bivalent ß-carboline derivative inhibits macropinocytosis-dependent entry of pseudorabies virus by targeting the kinase DYRK1A.

Pseudorabies virus (PRV) has become a "new life-threatening zoonosis" since the human-originated PRV strain was first isolated in 2020. To identify novel anti-PRV agents, we screened a total of 107 ß-carboline derivatives and found 20 compounds displaying antiviral activity against PRV. Among them, 14 compounds showed better antiviral activity than acyclovir. We found that compound 45 exhibited the strongest anti-PRV activity with an IC50 value of less than 40 nM. Our in vivo studies showed that treatment with 45 significantly reduced the viral loads and protected mice challenged with PRV. To clarify the mode of action of 45, we conducted a time of addition assay, an adsorption assay, and an entry assay. Our results indicated that 45 neither had a virucidal effect nor affected viral adsorption while significantly inhibiting PRV entry. Using the FITC-dextran uptake assay, we determined that 45 inhibits macropinocytosis. The actin-dependent plasma membrane protrusion, which is important for macropinocytosis, was also suppressed by 45. Furthermore, the kinase DYRK1A (dual-specificity tyrosine phosphorylation-regulated kinase 1A) was predicted to be a potential target for 45. The binding of 45 to DYRK1A was confirmed by drug affinity responsive target stability and cellular thermal shift assay. Further analysis revealed that knockdown of DYRK1A by siRNA suppressed PRV macropinocytosis and the tumor necrosis factor alpha-TNF-induced formation of protrusions. These results suggested that 45 could restrain PRV macropinocytosis by targeting DYRK1A. Together, these findings reveal a unique mechanism through which ß-carboline derivatives restrain PRV infection, pointing to their potential value in the development of anti-PRV agents.

Low-Concentration T-2 Toxin Attenuates Pseudorabies Virus Replication in Porcine Kidney 15 Cells.

Pseudorabies, caused by pseudorabies virus (PRV), is the main highly infectious disease that severely affects the pig industry globally. T-2 toxin (T2), a significant mycotoxin, is widely spread in food and feeds and shows high toxicity to mammals. The potential mechanism of the interaction between viruses and toxins is of great research value because revealing this mechanism may provide new ideas for their joint prevention and control. In this study, we investigated the effect of T2 on PRV replication and the mechanism of action. The results showed that at a low dose (10 nM), T2 had no significant effect on porcine kidney 15 (PK15) cell viability. However, this T2 concentration alleviated PRV-induced cell injury and increased cell survival time. Additionally, the number of PK15 cells infected with PRV significantly reduced by T2 treatment. Similarly, T2 significantly decreased the copy number of PRV. Investigation of the mechanism revealed that 10 nM T2 significantly inhibits PRV replication and leads to downregulation of oxidative stress- and apoptosis-related genes. These results suggest that oxidative stress and apoptosis are involved in the inhibition of PRV replication in PK15 cells by low-concentration T2. Taken together, we demonstrated the protective effects of T2 against PRV infection. A low T2 concentration inhibited the replication of PRV in PK15 cells, and this process was accompanied by downregulation of the oxidative stress and apoptosis signaling pathways. Our findings partly explain the interaction mechanism between T2 and PRV, relating to oxidative stress and apoptosis, though further research is required.

The Valproic Acid Derivative Valpromide Inhibits Pseudorabies Virus Infection in Swine Epithelial and Mouse Neuroblastoma Cell Lines.

Pseudorabies virus (PRV) infection of swine can produce Aujeszky's disease, which causes neurological, respiratory, and reproductive symptoms, leading to significant economic losses in the swine industry. Although humans are not the natural hosts of PRV, cases of human encephalitis and endophthalmitis caused by PRV infection have been reported between animals and workers. Currently, a lack of specific treatments and the emergence of new PRV strains against which existing vaccines do not protect makes the search for effective antiviral drugs essential. As an alternative to traditional nucleoside analogues such as acyclovir (ACV), we studied the antiviral effect of valpromide (VPD), a compound derived from valproic acid, against PRV infection in the PK15 swine cell line and the neuroblastoma cell line Neuro-2a. First, the cytotoxicity of ACV and VPD in cells was compared, demonstrating that neither compound was cytotoxic at a specific concentration range after 24 h exposure. Furthermore, the lack of direct virucidal effect of VPD outside of an infected cell environment was demonstrated. Finally, VPD was shown to have an antiviral effect on the viral production of two strains of pseudorabies virus (wild type NIA-3 and recombinant PRV-XGF) at the concentrations ranging from 0.5 to 1.5 mM, suggesting that VPD could be a suitable alternative to nucleoside analogues as an antiherpetic drug against Aujeszky's disease.

G-Quadruplexes Formation at the Upstream Region of Replication Origin (OriL) of the Pseudorabies Virus: Implications for Antiviral Targets.

Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease, which still causes large economic losses for the swine industry. Therefore, it is urgent to find a new strategy to prevent and control PRV infection. Previous studies have proven that guanine (G)-rich DNA or RNA sequences in some other viruses' genomes have the potential to form G-quadruplex (G4), which serve as promising antivirus targets. In this study, we identified two novel G4-forming sequences, OriL-A and OriL-S, which are located at the upstream origin of replication (OriL) in the PRV genome and conserved across 32 PRV strains. Circular dichroism (CD) spectroscopy and a gel electrophoresis assay showed that the two G-rich sequences can fold into parallel G4 structures in vitro. Moreover, fluorescence resonance energy transfer (FRET) melting and a Taq polymerase stop assay indicated that the G4 ligand PhenDC3 has the capacity to bind and stabilize the G4. Notably, the treatment of PRV-infected cells with G4-stabilizer PhenDC3 significantly inhibited PRV DNA replication in host cells but did not affect PRV's attachment and entry. These results not only expand our knowledge about the G4 characteristics in the PRV genome but also suggest that G4 may serve as an innovative therapeutic target against PRV.

A monoclonal antibody neutralizes pesudorabies virus by blocking gD binding to the receptor nectin-1.

Pseudorabies virus (PRV) was isolated from some human cases recently and the infected patients manifested respiratory dysfunction and acute neurological symptoms. However, no effective drug or vaccine, preventing the progression of PRV infection, is available. Nectin-1 was the only reported receptor for PRV cell entry both swine and human origin, representing an excellent target to block PRV infection, and especially its transmission from pigs to humans. A PRV-gD specific mAbs (10B6) was isolated from hybridomas and its neutralizing activities in vitro and in vivo were determined. 10B6 exhibited effective neutralizing activities in vitro with IC50 = 2.514 µg/ml and 4.297 µg/ml in the presence and absence of complement. And in vivo, 10B6 provided 100% protection against PRV lethal challenge with a dose of 15 mg/kg. Further, 10B6 could bind to a conserved epitope, 316QPAEPFP322, locating in gD pro-fusion domain, and finally blocks the binding of PRV-gD to nectin-1. Moreover, 10B6 showed an effective inhibition on PRV cell-attachment in a cell type-independent manner and could also block the virus spreading among cells. 10B6 exhibited effectively neutralizing activities to Chinese PRV variant strain in vitro and in vivo by blocking gD binding to nectin-1, implied both prophylactic and therapeutic interventions against PRV infections.

The antiviral activity of kaempferol against pseudorabies virus in mice.

BACKGROUND: Pseudorabies virus (PRV), a member of the Alphaherpesviruses, is one of the most important pathogens that harm the global pig industry. Accumulated evidence indicated that PRV could infect humans under certain circumstances, inducing severe clinical symptoms such as acute human encephalitis. Currently, there are no antiviral drugs to treat PRV infections, and vaccines available only for swine could not provide full protection. Thus, new control measures are urgently needed. RESULTS: In the present study, kaempferol exhibited anti-PRV activity in mice through improving survival rate by 22.22 %, which was higher than acyclovir (Positive control) with the survival rate of 16.67 % at 6 days post infection (dpi); meanwhile, the survival rate was 0 % at 6 dpi in the infected-untreated group. Kaempferol could inhibit the virus replication in the brain, lung, kidney, heart and spleen, especially the viral gene copies were reduced by over 700-fold in the brain, which was further confirmed by immunohistochemical examination. The pathogenic changes induced by PRV infection in these organs were also alleviated. The transcription of the only immediate-early gene IE180 in the brain was significantly inhibited by kaempferol, leading to the decreased transcriptional levels of the early genes (EPO and TK). The expression of latency-associated transcript (LAT) was also inhibited in the brain, which suggested that kaempferol could inhibit PRV latency. Kaempferol-treatment could induce higher levels of IL-1ß, IL-4, IL-6, TNF-α and IFN-γ in the serum at 3 dpi which were then declined to normal levels at 5 dpi. CONCLUSIONS: These results suggested that kaempferol was expected to be a new alternative control measure for PRV infection.

Carbonized Lysine-Nanogels Protect against Infectious Bronchitis Virus.

In this study, we demonstrate the synthesis of carbonized nanogels (CNGs) from an amino acid (lysine hydrochloride) using a simple pyrolysis method, resulting in effective viral inhibition properties against infectious bronchitis virus (IBV). The viral inhibition of CNGs was studied using both in vitro (bovine ephemeral fever virus (BEFV) and pseudorabies virus (PRV)) and in ovo (IBV) models, which indicated that the CNGs were able to prevent virus attachment on the cell membrane and penetration into the cell. A very low concentration of 30 µg mL-1 was found to be effective (>98% inhibition) in IBV-infected chicken embryos. The hatching rate and pathology of IBV-infected chicken embryos were greatly improved in the presence of CNGs. CNGs with distinctive virus-neutralizing activities show great potential as a virostatic agent to prevent the spread of avian viruses and to alleviate the pathology of infected avian species.

Inhibition of histone deacetylase 1 suppresses pseudorabies virus infection through cGAS-STING antiviral innate immunity.

Pseudorabies virus (PRV) is an enveloped double-stranded DNA virus that is the etiological agent of Aujeszky's disease in pigs. Vaccination is currently available to prevent PRV infection, but there is still an urgent need for new strategies to control this infectious disease. Histone deacetylases (HDACs) are epigenetic regulators that regulate the histone tail, chromatin conformation, protein-DNA interaction and even transcription. Viral transcription and protein activities are intimately linked to regulation by histone acetyltransferases and HDACs that remodel chromatin and regulate gene expression. We reported here that genetic and pharmacological inhibition of HDAC1 significantly influenced PRV replication. Moreover, we demonstrated that inhibition of HDAC1 induced a DNA damage response and antiviral innate immunity. Mechanistically, the HDAC1 inhibition-induced DNA damage response resulted in the release of double-strand DNA into the cytosol to activate cyclic GMP-AMP synthase and the downstream STING/TBK1/IRF3 innate immune signaling pathway. Our results demonstrate that an HDAC1 inhibitor may be used as a new strategy to prevent Aujeszky's disease in pigs.

CRISPR/Cas9-based generation of a recombinant double-reporter pseudorabies virus and its characterization in vitro and in vivo.

Pseudorabies, caused by pseudorabies virus (PRV) variants, has broken out among commercial PRV vaccine-immunized swine herds and resulted in major economic losses to the pig industry in China since late 2011. However, the mechanism of virulence enhancement of variant PRV is currently unclear. Here, a recombinant PRV (rPRV HN1201-EGFP-Luc) with stable expression of enhanced green fluorescent protein (EGFP) and firefly luciferase as a double reporter virus was constructed on the basis of the PRV variant HN1201 through CRISPR/Cas9 gene-editing technology coupled with two sgRNAs. The biological characteristics of the recombinant virus and its lethality to mice were similar to those of the parental strain and displayed a stable viral titre and luciferase activity through 20 passages. Moreover, bioluminescence signals were detected in mice at 12 h after rPRV HN1201-EGFP-Luc infection. Using the double reporter PRV, we also found that 25-hydroxycholesterol had a significant inhibitory effect on PRV both in vivo and in vitro. These results suggested that the double reporter PRV based on PRV variant HN1201 should be an excellent tool for basic virology studies and evaluating antiviral agents.

Inhibition of PARP1 Dampens Pseudorabies Virus Infection through DNA Damage-Induced Antiviral Innate Immunity.

Pseudorabies virus (PRV) is the causative pathogen of Aujeszky's disease in pigs. Although vaccination is currently applied to prevent the morbidity of PRV infection, new applications are urgently needed to control this infectious disease. Poly(ADP-ribose) polymerase 1 (PARP1) functions in DNA damage repair. We report here that pharmacological and genetic inhibition of PARP1 significantly influenced PRV replication. Moreover, we demonstrate that inhibition of PARP1 induced DNA damage response and antiviral innate immunity. Mechanistically, PARP1 inhibition-induced DNA damage response resulted in the release of double-stranded DNA (dsDNA) into the cytosol, where dsDNA interacted with cyclic GMP-AMP (cGAMP) synthase (cGAS). cGAS subsequently catalyzed cGAMP production to activate the STING/TBK1/IRF3 innate immune signaling pathway. Furthermore, challenge of mice with PARP1 inhibitor stimulated antiviral innate immunity and protected mice from PRV infection in vivo. Our results demonstrate that PARP1 inhibitors may be used as a new strategy to prevent Aujeszky's disease in pigs. IMPORTANCE Aujeszky's disease is a notifiable infectious disease of pigs and causes economic losses worldwide in the pig industry. The causative pathogen is PRV, which is a member of the subfamily Alphaherpesvirinae of the family Herpesviridae. PRV has a wide range of hosts, such as ruminants, carnivores, and rodents. More seriously, recent reports suggest that PRV can cause human endophthalmitis and encephalitis, which indicates that PRV may be a potential zoonotic pathogen. Although vaccination is currently the major strategy used to control the disease, new applications are also urgently needed for the pig industry and public health. We report here that inhibition of PARP1 induces DNA damage-induced antiviral innate immunity through the cGAS-STING signaling pathway. Therefore, PARP1 is a therapeutic target for PRV infection as well as alphaherpesvirus infection.

Design of fusion protein for efficient preparation of cyanovirin-n and rapid enrichment of pseudorabies virus.

OBJECTIVE: Cyanovirin-N (CVN) is a cyanobacterial protein with potent neutralizing activity against enveloped virus. To achieve the economic and functional production of CVN, the CVN N-terminally fused with CL7(A mutant of the Colicin E7 Dnase) was utilized to improve the solubility and stability of CVN fusion protein (CL7-CVN). Additionally, to improve the detection limit of existing PRV diagnostic assays, CL7-CVN was used for Pseudorabies virus (PRV) enrichment from larger sample volumes. RESULTS: CVN fused with CL7 was efficiently expressed at a level of ~ 40% of the total soluble protein in E. coli by optimizing the induction conditions. Also, the stability of CVN fusion protein was enhanced, and 10 mg of CVN with a purity of ~ 99% were obtained from 1 g of cells by one-step affinity purification with the digestion of HRV 3C protease. Moreover, both purified CVN and CL7-CVN could effectively inhibit the infection of PRV to PK15 cells. Considering the bioactivity of CL7-CVN, we explored a strategy for PRV enrichment from larger samples. CONCLUSIONS: CL7 effectively promoted the soluble expression of CVN fusion protein and improved its stability, which was meaningful for its purification and application. The design of CVN fusion protein provides an efficient approach for the economical and functional production of CVN and a new strategy for PRV enrichment.

Antiviral activity of porcine interferon delta 8 against pesudorabies virus in vitro.

Recently, pseudorabies virus (PRV) was isolated from human cases, and infected patients presented with respiratory dysfunction and acute neurological symptoms. However, there was no available effective drug to prevent the progression of PRV infection. In the present study, we screened a stably Drosophila S2 cell line which can secretory express a novel type I IFNs-interferon delta 8 (IFN-δ8) and the yield was about 10 mg/L. After purification, recombinant IFN-δ8 was demonstrated to be acid-stable, heat-stable, and nontoxic to PK-15 and 3D4/21 cells. Antiviral effects of IFN-δ8 against PRV were tested in vitro. Our results showed both pre- and post-treatment, recombinant PoIFN-δ8 exerted a significant protective effect against PRV infection in PK-15 and 3D4/21 cells. In addition, PoIFN-δ8 remarkably increased the expression of eight IFN-stimulated genes (ISGs), including ISG15, OAS1, PKR, MX1, CH25H, IFITM1, IFITM2 and IFITM3, to resist virus infection. These findings highlight the significance of IFN-δ8 that might serve as an antiviral agent for the prevention of PRV infection, and maybe expand the potential function of IFN antiviral drugs in the future.

Adefovir dipivoxil efficiently inhibits the proliferation of pseudorabies virus in vitro and in vivo.

Since 2011, highly pathogenic pseudorabies virus (PRV) variants that emerged on many farms in China have posed major economic burdens to the animal industry and have even recently caused several human cases of viral encephalitis. Currently, there are no approved effective drugs to treat PRV associated diseases in humans or pigs. Thus, it is important to develop a new effective drug for the treatment of PRV infection. To this end, we established a novel rapid method to screen drugs against PRV from 1818 kinds of small molecular drugs approved by the FDA. Using this method, we identified 21 kinds of them that can strongly suppress the proliferation of PRV. Mitoxantrone, puromycin dihydrochloride, mitoxantrone hydrochloride and adefovir dipivoxil effectively inhibited PRV in vitro. Of them, only adefovir dipivoxil could potently protect mice against lethal PRV infection. Our work identifies several kinds of potential therapeutics against PRV and may offer important guidance for controlling PRV epidemics and treating associated diseases in humans and animals.

Synthesis of "Nereid," a new phenol-free detergent to replace Triton X-100 in virus inactivation.

In the 1980s, virus inactivation steps were implemented into the manufacturing of biopharmaceuticals in response to earlier unforeseen virus transmissions. The most effective inactivation process for lipid-enveloped viruses is the treatment by a combination of detergents, often including Triton X-100 (TX-100). Based on recent environmental concerns, the use of TX-100 in Europe will be ultimately banned, which forces the pharmaceutical industry, among others, to switch to an environmentally friendly alternative detergent with fully equivalent virus inactivation performance such as TX-100. In this study, a structure-activity relationship study was conducted that ultimately led to the synthesis of several new detergents. One of them, named "Nereid," displayed inactivation activity fully equivalent to TX-100. The synthesis of this replacement candidate has been optimized to allow for the production of several kg of detergent at lab scale, to enable the required feasibility and comparison virus inactivation studies needed to support a potential future transition. The 3-step, chromatography-free synthesis process described herein uses inexpensive starting materials, has a robust and simple work-up, and allows production in a standard organic laboratory to deliver batches of several hundred grams with >99% purity.

Curcumin protects rat hippocampal neurons against pseudorabies virus by regulating the BDNF/TrkB pathway.

Pseudorabies virus (PRV) infection can elicit nervous system disorders. Curcumin has been reported to have neuroprotective effects. However, whether curcumin can protect neurons against PRV infection and the underlying mechanisms remain unclear. In the present study, for the first time, the protective effects of curcumin against PRV-induced oxidative stress, apoptosis, and mitochondrial dysfunction in rat hippocampal neurons and the brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) pathway were investigated. Results indicated that PRV with a titer of 3.06 × 106 TCID50 (50% tissue culture infective dose) induced oxidative damage of hippocampal neurons 2 h post-infection and that 10 µM curcumin improved the viability of PRV-infected hippocampal neurons. Blocking the BDNF/TrkB pathway reversed the neuroprotective effects of curcumin, which were imparted by decreasing the PRV-induced upregulation of nitric oxide synthase expression, repressing the PRV-activated mitochondrial apoptotic pathway, and mitochondrial dysfunction. To conclude, curcumin exhibited a neuroprotective role against PRV infection by upregulating the BDNF/TrkB pathway. This study provides insight into the anti-PRV neuroprotective application of curcumin and the underlying mechanism in the prophylaxis and treatment of neurological disorders caused by PRV infection.

Hydroquinone inhibits PRV infection in neurons in vitro and in vivo.

Pseudorabies virus (PRV) is a prevalent and endemic swine pathogen that causes significant economic losses in the global swine industry. Due to the emergence of PRV mutant strains in recent years, vaccines can't completely prevent and control PRV infection. Therefore, research and development of new vaccines and drugs with inhibitory effects on PRV are of great significance in the prevention and treatment of PR. In this study, we firstly screened a library of 44 FDA-approved drugs and found that hydroquinone (HQ) displayed high anti-PRV activity by inhibiting PRV adsorption onto and internalization into cells. This study revealed that hydroquinone treatment stimulated genes associated with the PI3K-AKT signal pathway. HQ increased AKT mRNA production and activated AKT phosphorylation in N2a cells. This finding suggests that HQ significantly inhibits PRV replication by activating the phosphorylation of AKT. We also conducted in vivo experiments in mice. Hydroquinone significantly reduced the viral loads in mouse tissues and the mortality after PRV infection. The above results indicate that hydroquinone significantly inhibits the replication of PRV mutant strain ZJ01 in ICR mice and has an inhibitory effect on PRV. This study will contribute to the development of a novel prophylactic and therapeutic strategy against PRV infection.

Isatis root polysaccharide promotes maturation and secretory function of monocyte-derived dendritic cells.

BACKGROUND: Pseudorabies virus (PRV) is an animal virus that is globally responsible for the high economic losses in the swine industry. Isatis root is a traditional Chinese medicinal herb that possesses immune-enhancing and antiviral properties. However, the molecular mechanisms underlying the effects of the active component of the isatis root polysaccharide (IRPS) extract on immature dendritic cells remain elusive. METHODS: In this study, we investigated the molecular changes in primary porcine peripheral blood monocyte-derived dendritic cells (MoDCs) during PRV infection, using enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcription-polymerase chain reaction. Additionally, we studied the effect of IRPS on PRV-infected DCs. RESULTS: The results showed that IRPS stimulated the maturation of MoDCs, induced IL-12 secretion, and downregulated IL-6 expression. CONCLUSIONS: Collectively, these results suggest that IRPS is a promising candidate for promoting maturation of DCs and enhancing their secretory potential after PRV infection.

Typical gene expression profile of pseudorabies virus reactivation from latency in swine trigeminal ganglion.

Pseudorabies virus (PRV) establishes a lifelong latent infection in swine trigeminal ganglion (TG) following acute infection. Increased corticosteroid levels, due to stress, increases the incidence of reactivation from latency. Muscle injection combined with intravenous deliver of the synthetic corticosteroid dexamethasone (DEX) consistently induces reactivation from latency in pigs. In this study, PRV-free piglets were infected with PRV. Viral shedding in nasal and ocular swabs demonstrated that PRV infection entered the latent period. The anti-PRV antibody was detected by enzyme-linked immunosorbent assay and the serum neutralization test, which suggested that the PRV could establish latent infection in the presence of humoral immunity. Immunohistochemistry and viral genome detection of TG neurons suggested that PRV was reactivated from latency. Viral gene expressions of IE180, EP0, VP16, and LLT-intron were readily detected at 3-h post-DEX treatment, but gB, a γ1 gene, was not detectable. The differentially expressed phosphorylated proteins of TG neurons were analyzed by ITRAQ coupled with LC-MS/MS, and p-EIF2S2 differentially expression was confirmed by western blot assay. Taken together, our study provides the evidence that typical gene expression in PRV reactivation from latency in TG is disordered compared with known lytic infection in epithelial cells.