Phloretin inhibits transmissible gastroenteritis virus proliferation via multiple mechanisms.

Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, has caused huge economic losses to the pig industry, with 100% mortality in piglets aged 2 weeks and intestinal injury in pigs of other ages. However, there is still a shortage of safe and effective anti-TGEV drugs in clinics. In this study, phloretin, a naturally occurring dihydrochalcone glycoside, was identified as a potent antagonist of TGEV. Specifically, we found phloretin effectively inhibited TGEV proliferation in PK-15 cells, dose-dependently reducing the expression of TGEV N protein, mRNA, and virus titer. The anti-TGEV activity of phloretin was furthermore refined to target the internalization and replication stages. Moreover, we also found that phloretin could decrease the expression levels of proinflammatory cytokines induced by TGEV infection. In addition, we expanded the potential key targets associated with the anti-TGEV effect of phloretin to AR, CDK2, INS, ESR1, ESR2, EGFR, PGR, PPARG, PRKACA, and MAPK14 with the help of network pharmacology and molecular docking techniques. Furthermore, resistant viruses have been selected by culturing TGEV with increasing concentrations of phloretin. Resistance mutations were reproducibly mapped to the residue (S242) of main protease (Mpro). Molecular docking analysis showed that the mutation (S242F) significantly disrupted phloretin binding to Mpro, suggesting Mpro might be a potent target of phloretin. In summary, our findings indicate that phloretin is a promising drug candidate for combating TGEV, which may be helpful for developing pharmacotherapies for TGEV and other coronavirus infections.

MAb Targeting a Link Between ExoN and MTase of TGEV NSP14.

Porcine transmissible gastroenteritis virus (TGEV) infection results in severe gastrointestinal disease manifesting vomiting, diarrhea in neonatal porcine, with extremely high mortality. Monoclonal antibody (MAb) specific to TGEV nonstructural protein (NSP)14 that contains two functional domains, exonuclease (ExoN) and methyltransferase (MTase) domains, may help elucidate the role of NSP14 in the viral life-cycle. In this study, we developed a murine MAb, designated 12F1, against TGEV NSP14 using traditional cell-fusion technique. It was shown the MAb can exclusively bind to viral NSP14, as evidenced by the results of indirect fluorescent assay and western blotting. Intriguingly, epitope screening assay shown that 12F1 targets a hinge region connecting ExoN and N7-MTase of NSP14.

Effects of Pretreated Phosphogypsum and Granulated Blast-Furnace Slag on the Rheological Properties of the Paste Excited by NaOH.

The main component of phosphogypsum (PG) is CaSO4·2H2O. PG contains a few impurities, heavy metals, and radioisotopes, which limit the use of PG and pose a danger to the environment. In this study, under the excitation of a sodium hydroxide solution, the rheological properties of a paste with granulated blast-furnace slag (GGBS) and PG treated with ultrasonic water washing were investigated. Experimental results showed that the ratio of GGBS to PG and the amount of sodium hydroxide solution significantly affect the density and viscosity of the paste, but the effect patterns of both are different. The maximum viscosity was 498 mPa·s when the ratio of GGBS to PG was 4:1. When the ratio changed from 3:2 to 1:4, the viscosity of the paste gradually decreased by 15.5%, 32.1%, 36.1%, and 46.8%, respectively. In contrast, the ratio of GGBS to PG had a greater effect on the viscosity than the amount of sodium hydroxide solution in terms of the standard consistency water consumption, viscosity, and water release ratio. The larger the PG ratio, the smaller the density, viscosity, and water release ratio of the paste. The variation in the ratio of GGBS to PG had a significant effect on the water film thickness of the paste, demonstrating that the larger the PG mixture, the larger the water film thickness of the paste, which reached 1.122 µm, 2.31 times the minimum water film thickness of the paste. At the same time, the water film thickness of the paste was negatively correlated with the water consumption of the standard consistency, viscosity, and water release ratio, and was positively correlated with the fluidity.

Advances in vaccinia virus-based vaccine vectors, with applications in flavivirus vaccine development.

Historically, virulent variola virus infection caused hundreds of millions of deaths. The smallpox pandemic in human beings has spread for centuries until the advent of the attenuated vaccinia virus (VV) vaccine, which played a crucial role in eradicating the deadly contagious disease. Decades of exploration and utilization have validated the attenuated VV as a promising vaccine vehicle against various lethal viruses. In this review, we focus on the advances in VV-based vaccine vector studies, including construction approaches of recombinant VV, the impact of VV-specific pre-existing immunity on subsequent VV-based vaccines, and antigen-specific immune responses. More specifically, the recombinant VV-based flaviviruses are intensively discussed. Based on the publication data, this review aims to provide valuable insights and guidance for future VV-based vaccine development.

Intranasal immunization with recombinant Vaccinia virus encoding trimeric SARS-CoV-2 spike receptor-binding domain induces neutralizing antibody.

Respiratory transmission of SARS-CoV-2 is considered to be the major dissemination route for COVID-19, therefore, mucosal immune responses have great importance in preventing SARS-CoV-2 from infection. In this study, we constructed a recombinant Vaccinia virus (VV) harboring trimeric receptor-binding domain (RBD) of SARS-CoV-2 spike protein (VV-tRBD), and evaluated the immune responses towards RBD following intranasal immunization against mice and rabbits. In BALB/c mice, intranasal immunization with VV-tRBD elicited robust humoral and cellular immune responses, with high-level of both neutralizing IgG and IgA in sera against SARS-CoV-2 psudoviruses, and a number of RBD-specific IFN-γ-secreting lymphocytes. Sera from immunized rabbits also exhibited neutralization effects. Notably, RBD-specific secretory IgA (sIgA) in both nasal washes and bronchoalveolar lavage fluids (BALs) were detectable and showed substantial neutralization activities. Collectively, a recombinant VV expressing trimeric RBD confers robust systemic immune response and mucosal neutralizing antibodies, thus warranting further exploration as a mucosal vaccine.

Properties and Microstructure of Na2CO3-Activated Binders Modified with Ca(OH)2 and Mg(OH)2.

Delayed strength development and long setting times are the main disadvantageous properties of Na2CO3-activated slag cements. In this work, combined auxiliary activators of Ca(OH)2 and Mg(OH)2 were incorporated in one-part Na2CO3-activated slag binders to accelerate the kinetics of alkali activation. The properties and microstructure evolution were investigated to clarify the reaction mechanism. The results showed that the additions of auxiliary activators promoted the hardening of the pastes within 2 h. The 28 days compressive strengths were in the range of 39.5-45.5 MPa, rendering the binders practical cementitious materials in general construction applications. Ca(OH)2 was more effective than Mg(OH)2 in accelerating the kinetics of alkali activation. The dissolution of Ca(OH)2 released more OH- and Ca2+ ions in the aqueous phase to increase alkalinity in the aqueous phase and promote the formation of the main binding gel phase of calcium-aluminosilicate hydrate (C-A-S-H). An increase in the Ca(OH)2/Mg(OH)2 ratios increased autogenous shrinkage and decreased drying shrinkage of the binders. The formation of a compact pore structure restricted the water evaporation from the binders during the drying procedure.

SARS_CoV2 RBD gene transcription cannot be driven by CMV promoter.

Cytomegalovirus (CMV) promoter drives various gene expression and yields sufficient protein for further functional investigation. Receptor binding domain (RBD) on spike protein of the SARS_CoV2 is the most critical portal for virus infection. Thus native conformational RBD protein may facilitate biochemical identification of RBD and provide valuable support of drug and vaccine design for curing COVID-19. We attempted to express RBD under CMV promoter in vitro, but failed. RBD-specific mRNA cannot be detected in cell transfected with recombinant plasmids, in which CMV promoter governs the RBD transcription. Additionally, the pCMV-Tag2B-SARS_CoV2_RBD trans-inactivates CMV promoter transcription activity. Alternatively, we identified that both Chicken ß-actin promoter and Vaccinia virus-specific medium/late (M/L) promoter (pSYN) can highly precede SARS_CoV2 RBD expression. Our findings provided evidence that SARS_CoV2 RBD gene can be driven by Chicken ß-actin promoter or Vaccinia virus-specific medium/late promoter instead of CMV promoter, thus providing valuable information for RBD feature exploration.

Hydration and Strength Development of Cementitious Materials Prepared with Phosphorous-Bearing Clinkers.

To rationally use low-grade phosphorous limestone as the raw materials for cement production, the influence of phosphorous introduced by fluorapatite during the clinker calcination process on the mechanical properties of cementitious materials is investigated. Hydration kinetics, phase evolutions, and microstructure of cement pastes have been studied by using calorimetry, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate that the mechanical properties of cementitious materials can be slightly improved due to the mineralization effect of the small amount of phosphorous in the clinker and significantly decreased with an increase of phosphorous. High content of phosphorous will reduce the content of C3S and make the formation of α'-C2S-xC3P(x: 0-0.05), whose hydration reactivity is rather lower, such that on the one hand less-hydrated products, such as calcium silicate hydrate (C-S-H) gel, can be obtained, and on the other hand, the hydration reaction will be slowed by severely prolonging the induction period. Interestingly, small particles can be observed on the surface of hydration products, but no new phase can be detected by XRD. When the content of P2O5 is 2.0%, the cement can meet the requirements of P·II 42.5 cement in China. Hopefully, this can provide significant guidance for the use of cement prepared by fluorapatite as raw material.

Antiviral and virucidal effects of curcumin on transmissible gastroenteritis virus in vitro.

Emerging coronaviruses represent serious threats to human and animal health worldwide, and no approved therapeutics are currently available. Here, we used Transmissible gastroenteritis virus (TGEV) as the alpha-coronavirus model, and investigated the antiviral properties of curcumin against TGEV. Our results demonstrated that curcumin strongly inhibited TGEV proliferation and viral protein expression in a dose-dependent manner. We also observed that curcumin exhibited direct virucidal abilities in a dose-, temperature- and time-dependent manner. Furthermore, time-of-addition assays showed that curcumin mainly acted in the early phase of TGEV replication. Notably, in an adsorption assay, curcumin at 40 µM resulted in a reduction in viral titres of 3.55 log TCID50 ml-1, indicating that curcumin possesses excellent inhibitory effects on the adsorption of TGEV. Collectively, we demonstrate for the first time that curcumin has virucidal activity and virtual inhibition against TGEV, suggesting that curcumin might be a candidate drug for effective control of TGEV infection.

Antimicrobial peptide CAMA-syn expressed in pulmonary epithelium by recombination adenovirus inhibited the growth of intracellular bacteria.

BACKGROUND: Intracellular bacteria, especially Mycobacterium tuberculosis, are important pathogenic microorganisms that endanger human health. Purified and synthesized cecropin A-magainin 2 (CAMA-syn) can exhibit a higher antibacterial activity and lower cytotoxicity. To enhance such antimicrobial potential, it would be desirable to deliver CAMA-syn expressed in lung epithelial cells by an adenovirus vector using gene therapy. METHODS: A549 cells in vitro and lung epithelial cells in vivo were used to express CAMA-syn by transducing recombinant adenovirus Ad-SPC-CAMA/GFP, and the expression of CAMA-syn was determined by a reverse transcriptase-polymerase reaction (RT-PCR) and immunofluorescence. The antimicrobial activity in cells was investigated by colony-forming rate and growth curve. Forty Kunming mice of a Bacillus Calmette-Guerin (BCG) infection animal model were randomly divided into three groups: adenoviruses delivery of Ad-SPC-CAMA/GFP, Ad-CMV-CAMA/GFP and empty-virus Ad-CMV-GFP. The expression of CAMA-syn in mice was confirmed by RT-PCR and immunofluorescence. After tracheal injection of adenoviral vector for 3 days, lungs from the mouse model were extracted and homogenized for detection of colony-forming efficiency. RESULTS: CAMA-syn expressed in lung epithelial cells A549 conferred antimicrobial activity against a series of bacteria, including Salmonella abortusovis and BCG. The results obtained in vivo showed that the colony-forming rate of Ad-SPC-CAMA/GFP (74.54%) and Ad-CMV-CAMA/GFP (62.31%) transduced into mice was significantly lower than that of the control group. CONCLUSIONS: Lung epithelial-specific expression of antimicrobial peptide CAMA-syn mediated by adenovirus suppressed the growth of intracellular bacteria, providing a promising approach for the control of refractory intracellular infection.

Monoclonal Antibody Targeting a Conserved N-Terminal Epitope on 2Apro of Enteroviruses.

Several members of enteroviruses (EVs) that belong to the EVs A and B species cause hand, foot, and mouth disease (HFMD) in infants and young children. The virus-specific protease 2Apro is conserved in all the EV species, thus developing a monoclonal antibody (mAb) against 2Apro may facilitate the identification from the HFMD-associated pathogens. In this study, we achieved a murine mAb, named 5A3, specifically toward EVA71 2Apro by using the traditional hybridoma technique. The mAb 5A3 recognizes 2Apro of both EVs A and B species, which was demonstrated by indirect fluorescent assay and Western blotting. Furthermore, a conserved N-terminal epitope on 2Apro recognized by mAb 5A3 was defined by using an overlapping peptide-based enzyme-linked immunosorbent assay (ELISA). Therefore, the unique mAb targeting conserved EVs 2Apro can be used as an important tool during both identifying the causative agent of HFMD and elucidating the pathological mechanism of HFMD.

Intranasal immunization with recombinant Vaccinia virus Tiantan harboring Zaire Ebola virus gp elicited systemic and mucosal neutralizing antibody in mice.

Accumulating literature revealed that human mucosa was likely one of the important routes for EBOV attachment and further infection. Therefore inducing effective mucosal immune responses play key role in preventing the virus infection. Vaccinia virus Tiantan strain (VV) was a remarkably attenuated poxvirus, which has been broadly exploited as a multifunctional vector during the development of genetically recombinant vaccine and cancer therapeutic agent. In this study, we generated a recombinant VV harboring EBOV gp (VV-Egp) that was used to immunize mice, followed by assessing immune responses, particularly the mucosal immune responses to EBOV GP. A stable and further attenuated VV-Egp, in which the VV ha gene was replaced with the EBOV gp, was generated. In BALB/c mouse model, intranasal immunization with VV-Egp elicited robust humoral and cellular immune responses, including high level of neutralizing serum IgG and IgA against EBOV, and a large amount of GP-specific IFN-γ secreting lymphocytes. More importantly, EBOV GP-specific neutralizing secreted IgA (sIgA) in nasal wash and both sIgA and IgG in vaginal wash were induced. In summary, immunization with a safe and stable recombinant VV carrying a single EBOV gp conferred robust systemic immune response and mucosal neutralizing antibodies, indicating that the recombinant virus could be utilized as a viral vector for plug-and-play universal platform in mucosal vaccine development.

Dual monoclonal antibody-based sandwich ELISA for detection of in vitro packaged Ebola virus.

BACKGROUND: Rapid transmission and high mortality of Ebola virus disease (EVD) highlight a urgent need of large scale, convenient and effective measure for Ebola virus screening. Application of monoclonal antibodies (mAbs) are crucial for establishment of an enzyme-linked immunosorbent assay (ELISA) with high sensitivity and specificity. METHODS: The traditional cell fusion technique was used to generate a panel of hybridomas. Two mAbs were characterized by SDS-PAGE, Western blot, Indirect immunofluorescence assay (IFA). A sandwich ELISA was established using the two mAbs. The detection capability of the ELISA was evaluated. RESULTS: In the current study, we produced two murine-derived mAbs (designated as 6E3 and 3F21) towards Zaire Ebola virus glycoprotein (GP), the major viral transmembrane spike protein associated with viral attachment. It was shown that 6E3 and 3F21 recognized GP1 and GP2 subunits of the GP respectively. Furthermore, 6E3 and 3F21 bound to corresponding epitopes on GP without reciprocal topographical interpretation. Subsequently, a sandwich ELISA based on the two mAbs were established and evaluated. The detection limit was 3.6 ng/ml, with a linear range of 3.6-100 ng/ml. More importantly, Ebola virus like particles (eVLPs) were able to be detected by this established virus detection measure. CONCLUSIONS: We produced and characterized two murine-derived mAbs (designated as 6E3 and 3F21) towards Zaire Ebola virus glycoprotein (GP), and established a sandwich ELISA based on the mAbs. It was suggested that the sandwich ELISA provided an alternative method for specific and sensitive detection of Ebola virus in the field setting.

Evidence for Multiple Applications of Monoclonal Antibody 5G10.

We had earlier obtained a murine monoclonal antibody (mAb), termed 5G10, that bound to Salmonella flagellin (SF) and subsequently impaired the latter property of Toll-like receptor 5 (TLR5) signaling activation. Besides interrupting SF-mediated TLR5 activation, mAb 5G10 probably had other potential applications. In this study, we explored multiple functions of 5G10. A short peptide QRVRELAV (designated T5) derived from SF in either terminal of proteins was specifically recognized by 5G10. T5 tag expressed in eukaryotic cell was also detected by 5G10 when analyzed by Western blot, immunofluorescence assay (IFA), and fluorescent-activated cell sorting (FACS). The result of the co-immunoprecipitation assay showed that 5G10 as a bait antibody dragged out the complex of enterovirus 71 (EV71) 2A and mitochondrial antiviral signaling (MAVS) protein. More importantly, 5G10 helped to purify fusion proteins T5-tagged (EV71) 2A and T5-Japanese encephalitis virus NS5 methyltransferase (MTase). Thus, it has been suggested that mAb 5G10 could be useful in several biological applications, including protein identification, location, and affinity purification.

Targeting expression of antimicrobial peptide CAMA-Syn by adenovirus vector in macrophages inhibits the growth of intracellular bacteria.

Although purified and synthesized Cecropin A-magainin 2 (CAMA-syn) shows potent antibacterial activity in vitro, its ability to inhibit bacteria within mammal cells mediated by virus vector has not yet been investigated. To enhance its antimicrobial potential and reduce systemic side effects, it would be desirable to deliver CAMA-syn in macrophages by adenovirus vector. In this study,recombinant adenovirus Ad-MSP-CAMA/GFP were used to infect macrophages RAW264.7 cells in vitro and macrophages cells of lungs in vivo and the expression of CAMA-syn was detected by RT-PCR and observation of co-expression of GFP. Antimicrobial activity in cells was evaluated by colony enumeration. The results showed that expression of CAMA-syn in macrophages conferred antimicrobial activity against a series of bacteria, including E. coli and BCG(Bacillus Calmette-Guérin). To establish BCG infection animal model, 40 Kunming mice were randomly divided into the following four groups: adenoviral delivery of Ad-MSP-CAMA/GFP, Ad-CMV-CAMA/GFP, empty-virus Ad-GFP, and control PBS, respectively. The expression of CAMA-syn in mouse was confirmed by real-time PCR and GFP co-expression. In brief, 3 days after injection of adenoviral vector, mice were scarified, different tissues were sectioned and homogenized and colony-forming efficiency by these treated tissues was determined. The colony-forming efficiency of Ad-MSP-CAMA/GFP (78.31%) and Ad-CMV-CAMA/GFP (61.68%) showed significant reduction compared to control groups. No inhibition of bacterial colony was observed from tissues treated by the PBS or empty-virus control. In conclusion, our results demonstrated that macrophages-specific expression of antimicrobial peptide CAMA-syn in macrophages inhibited the growth of intracellular bacteria, providing a promise approach for the control of refractory intracellular infection.

Cellular RNA Helicase DDX1 Is Involved in Transmissible Gastroenteritis Virus nsp14-Induced Interferon-Beta Production.

Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus (CoV) of porcine, causes lethal watery diarrhea and severe dehydration in piglets and leads to severe economic losses in the swine industry. Unlike most CoVs that antagonize type I interferon (IFN) production, previous studies showed that TGEV infection induces IFN-I production both in vivo and in vitro. However, the underlying mechanism(s) remain largely unknown. In this study, we found that TGEV infection significantly facilitated IFN-ß production as well as activation of the transcription factors IFN regulatory factor 3 (IRF3) and nuclear factor-kappaB (NF-κB) in porcine kidney (PK-15) cells. Screening of TGEV-encoded proteins demonstrated that non-structural protein 14 (nsp14) was the most potent IFN-ß inducer and induced IFN-ß production mainly by activating NF-κB but not IRF3. Further analysis showed that nsp14 interacted with DDX1, a member of the DExD/H helicase family. Knockdown of DDX1 by specific small interfering RNA (siRNA) significantly decreased nsp14-induced IFN-ß production and NF-κB activation. Furthermore, TGEV-induced IFN-ß production and IFN-stimulated gene (ISG) expression were decreased in cells transfected with DDX1-specific siRNA, indicating the vital role of DDX1 to TGEV-induced IFN-ß responses. In summary, our data revealed a potential coactivator role of host RNA helicase DDX1 to the induction of IFN-ß response initiated by TGEV and demonstrated that nsp14 is an important IFN inducer among the TGEV-encoded proteins.

Transmissible gastroenteritis virus infection induces NF-κB activation through RLR-mediated signaling.

Transmissible gastroenteritis virus (TGEV) is a porcine enteric coronavirus which causes lethal severe watery diarrhea in piglets. The pathogenesis of TGEV is strongly associated with inflammation. In this study, we found that TGEV infection activates transcription factors NF-κB, IRF3 and AP-1 in a time- and dose-dependent manner in porcine kidney cells. Treatment with the NF-κB-specific inhibitor BAY11-7082 significantly decreased TGEV-induced proinflammatory cytokine production, but did not affect virus replication. Phosphorylation of NF-κB subunit p65 and proinflammatory cytokine production were greatly decreased after knockdown of retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) or its adaptors MAVS and STING, while only slight reduction was observed in cells following silencing of Toll-like receptor adaptors, MyD88 and TRIF. Furthermore, TGEV infection significantly upregulated mRNA expression of RIG-I and MDA5. Taken together, our results indicate that the RLR signaling pathway is involved in TGEV-induced inflammatory responses.

Porcine bocavirus NP1 protein suppresses type I IFN production by interfering with IRF3 DNA-binding activity.

Type I interferon (IFN) and the IFN-induced cellular antiviral responses are the primary defense mechanisms against viral infection; however, viruses always evolve various mechanisms to antagonize this host's IFN responses. Porcine bocavirus (PBoV) is a newly identified porcine parvovirus. In this study, we found that the nonstructural protein NP1 of PBoV inhibits Sendai virus-induced IFN-ß production and the subsequent expression of IFN-stimulating genes (ISGs). Ectopic expression of NP1 significantly impairs IRF3-mediated IFN-ß production; however, it does not affect the expression, phosphorylation, and nuclear translocation of IRF3, the most important transcription factor for IFN synthesis. Coimmunoprecipitation and Chromatin immunoprecipitation assays suggested that NP1 interacts with the DNA-binding domain of IRF3, which in turn blocks the association of IRF3 with IFN-ß promoter. Together, our findings demonstrated that PBoV encodes an antagonist inhibiting type I IFN production, providing a better understanding of the PBoV immune evasion strategy.

Porcine bocavirus NP1 negatively regulates interferon signaling pathway by targeting the DNA-binding domain of IRF9.

To subvert host antiviral immune responses, many viruses have evolved countermeasures to inhibit IFN signaling pathway. Porcine bocavirus (PBoV), a newly identified porcine parvovirus, has received attention because it shows clinically high co-infection prevalence with other pathogens in post-weaning multisystemic wasting syndrome (PWMS) and diarrheic piglets. In this study, we screened the structural and non-structural proteins encoded by PBoV and found that the non-structural protein NP1 significantly suppressed IFN-stimulated response element (ISRE) activity and subsequent IFN-stimulated gene (ISG) expression. However, NP1 affected neither the activation and translocation of STAT1/STAT2, nor the formation of the heterotrimeric transcription factor complex ISGF3 (STAT1/STAT2/IRF9). Detailed analysis demonstrated that PBoV NP1 blocked the ISGF3 DNA-binding activity by combining with the DNA-binding domain (DBD) of IRF9. In summary, these results indicate that PBoV NP1 interferes with type I IFN signaling pathway by blocking DNA binding of ISGF3 to attenuate innate immune responses.

Quantitative proteomic analysis reveals that transmissible gastroenteritis virus activates the JAK-STAT1 signaling pathway.

Transmissible gastroenteritis virus (TGEV), a porcine enteropathogenic coronavirus, causes lethal watery diarrhea and severe dehydration in piglets. In this study, liquid chromatography-tandem mass spectrometry coupled to isobaric tags for relative and absolute quantification labeling was used to quantitatively identify differentially expressed cellular proteins after TGEV infection in PK-15 cells. In total, 162 differentially expressed cellular proteins were identified, including 60 upregulated proteins and 102 downregulated proteins. These differentially expressed proteins were involved in the cell cycle, cellular growth and proliferation, the innate immune response, etc. Interestingly, many upregulated proteins were associated with interferon signaling, especially signal transducer and activator of transcription 1 (STAT1) and interferon-stimulated genes (ISGs). Immunoblotting and real-time quantitative reverse transcription polymerase chain reaction demonstrated that TGEV infection induces STAT1 phosphorylation and nuclear translocation, as well as ISG expression. This study for the first time reveals that TGEV induces interferon signaling from the point of proteomic analysis.