Use of HSF1 protein and its coding gene in preparation of medicine for inhibiting PRRSV infection

Abstract

The application discloses a kind of HSF1 protein and its coding gene in preparation inhibiting PRRSV infection The application of drug, belong to the technical field of veterinary biological products.It is found that HSF1 has inhibiting effect on a variety of PRRSV epidemic strains, and the PRRSV epidemic strains include HP-PRRSV, NADC30-like PRRSV, NADC30 recombinant PRRSV, LP-PRRSV and type 1 PRRSV etc..Therefore, HSF1 does not only play an antiviral role against a single strain, but also has a broad-spectrum antiviral activity against PRRSV of different genotypes and different epidemic lineages, which can provide a host factor-based antiviral intervention means for the prevention and control of PRRSV.

Description

Technical Field

[0001] This invention relates to the field of veterinary biological products technology, specifically to the application of an HSF1 protein and its encoding gene in the preparation of drugs that inhibit PRRSV infection. Background Technology

[0002] Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious disease caused by porcine reproductive and respiratory syndrome virus (PRRSV), which seriously threatens the pig industry. PRRSV primarily infects porcine alveolar macrophages, leading to abortion, stillbirth in pregnant sows, and severe respiratory symptoms in piglets. This virus is characterized by rapid genetic mutation, complex serotypes, and strong immune evasion capabilities. Existing vaccines offer limited cross-protection against heterologous strains, and there are currently no specific antiviral drugs. Therefore, there is an urgent need to develop novel antiviral strategies.

[0003] PRRSV is a single-stranded positive-sense RNA virus whose genome encodes multiple structural and non-structural proteins. During infection, PRRSV antagonizes the host's innate immune response through various mechanisms, including inhibiting type I interferon production, interfering with dendritic cell maturation, and inducing immune tolerance, thereby achieving persistent infection and immune evasion. Recent studies have shown that host innate immune molecules play a crucial role in limiting PRRSV infection, and antiviral strategies targeting host factors have become a research hotspot.

[0004] Heat shock factor 1 (HSF1) is a core transcription factor that regulates the expression of heat shock proteins and belongs to the HSF family. It has been extensively studied in the fields of cellular stress, protein homeostasis, inflammation, tumors, and neurodegenerative diseases, but its role in PRRSV infection remains unclear. Summary of the Invention

[0005] In view of the above-mentioned prior art, the purpose of this invention is to provide an application of the HSF1 protein and its encoding gene in the preparation of drugs for inhibiting PRRSV infection. This invention is the first to discover that the HSF1 protein has significant antiviral activity against multiple circulating strains of PRRSV, and can significantly reduce viral replication levels and the number of infected cells, which is of great significance for the prevention and treatment of PRRSV infection.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides the use of HSF1 protein in the preparation of a medicament for inhibiting PRRSV infection; said HSF1 protein is a protein as shown in (A1) or (A2) below: (A1) A protein consisting of the amino acid sequence shown in SEQ ID NO.1 of the sequence listing; (A2) A fusion protein obtained by attaching a protein tag to the N-terminus and / or C-terminus of the protein defined in (A1).

[0007] In the aforementioned proteins, the protein tag refers to a polypeptide or protein fragment fused with the target protein using in vitro DNA recombination technology. This tag can be used to improve the expression efficiency of the target protein or to facilitate its detection, localization, separation, and / or purification. To facilitate the detection, separation, or purification of the (A1) protein, a protein tag can be attached to the amino and / or carboxyl terminus of the (A1) protein as needed. The protein tag includes, but is not limited to, one or more of the following: Poly-His tag, HA tag, Flag tag, c-Myc tag, and GST tag. Specifically, the Poly-His tag can be a tag composed of multiple histidine residues, such as a 6×His tag with the amino acid sequence HHHHHH; the HA tag can have the amino acid sequence YPYDVPDYA; the Flag tag can have the amino acid sequence DYKDDDDK; and the c-Myc tag can have the amino acid sequence EQKLISEEDL.

[0008] In the above applications, the HSF1 protein inhibits PRRSV infection through at least one of the following pathways (1)-(4): (1) Neutralize PRRSV viral particles; (2) Interferes with the internalization process of PRRSV entering the host cell; (3) Inhibit PRRSV genome replication in host cells; (4) It hinders the assembly and release of PRRSV progeny virus particles.

[0009] In the above applications, the PRRSV type is at least one of HP-PRRSV, NADC30-like, NADC30, LP-PRRSV, and Type 1 PRRSV.

[0010] In the above applications, the effective concentration of HSF1 protein in the drug is 10-40 μg / mL; preferably 30 μg / mL.

[0011] Furthermore, the drug also contains veterinary pharmaceutically acceptable excipients, including one or more of the following: stabilizers (such as trehalose and mannitol), preservatives (such as benzalkonium chloride and parabens), isotonic adjusters (such as sodium chloride and glucose), pH buffers (such as phosphate buffer and Tris-HCl), surfactants (such as Tween-80 and poloxamer), thickeners (such as hydroxypropyl methylcellulose and carbomer), and antioxidants (such as vitamin E and butylated hydroxyanisole). For example, trehalose can act as a protein stabilizer to protect the activity of HSF1 protein during lyophilization; poloxamer 188 can act as a surfactant to improve the solubility and dispersibility of the protein; and hydroxypropyl methylcellulose can act as a sustained-release matrix material to prolong the duration of action of the drug in vivo.

[0012] Furthermore, the dosage form of the drug is a lyophilized powder injection, an aqueous injection, an oral solution, a nasal spray, or a feed premix.

[0013] A second aspect of the present invention provides the use of the gene encoding the HSF1 protein in the preparation of a medicament for inhibiting PRRSV infection; the gene encoding the HSF1 protein is a nucleic acid molecule as shown in i) or ii) below: i) The nucleotide sequence is the nucleic acid molecule shown in SEQ ID NO.2; ii) Nucleic acid molecules other than those in i) that encode the amino acid sequence shown in SEQ ID NO.1.

[0014] In the above applications, PRRSV infection is suppressed by promoting the expression of the gene encoding the HSF1 protein.

[0015] Preferably, the substance that promotes the expression of the gene encoding the HSF1 protein is any one of the following: C1) Expression cassette containing the gene encoding the HSF1 protein; C2) A recombinant vector containing the gene encoding the HSF1 protein, or a recombinant vector containing the expression cassette described in C1); C3) Recombinant microorganisms containing the gene encoding the HSF1 protein, or recombinant microorganisms containing the expression cassette described in C1), or recombinant microorganisms containing the recombinant vector described in C2).

[0016] In the above applications, the PRRSV type is at least one of HP-PRRSV, NADC30-like, NADC30, LP-PRRSV, and Type 1 PRRSV.

[0017] The beneficial effects of this invention are: (1) This invention found that HSF1 has an inhibitory effect on multiple circulating PRRSV strains, including HP-PRRSV, NADC30-like PRRSV, NADC30 recombinant PRRSV, LP-PRRSV, and type 1 PRRSV. This indicates that HSF1 does not only exert antiviral effects against a single strain, but also has broad-spectrum antiviral activity against PRRSV of different genotypes and different circulating lineages, which can provide a host factor-based antiviral intervention for the prevention and control of PRRSV.

[0018] (2) This invention demonstrates that HSF1 can exert inhibitory effects at multiple stages of the PRRSV infection cycle, including reducing the infectivity of viral particles, inhibiting viral adsorption to host cells, interfering with viral internalization, inhibiting viral replication, and reducing viral release. Compared with antiviral methods that only act on a single stage of the viral infection cycle, this invention restricts PRRSV infection and proliferation at multiple stages, which helps to improve the stability of the antiviral effect and reduce the risk of single-target failure due to viral mutation.

[0019] (3) Since HSF1 is a host-derived innate immune-related factor, this invention provides a new technical approach for PRRSV prevention and control from the perspective of host antiviral factor regulation. This technical approach does not rely entirely on the matching of viral surface antigens, which helps to make up for the problem of insufficient cross-protection effect of existing vaccines between different PRRSV circulating strains, and is especially suitable for prevention and control scenarios with diverse PRRSV strains, frequent recombination, and continuous changes in circulating strains. Attached Figure Description

[0020] Figure 1 : HSF1 Gene expression in prokaryotes; in the diagram, A represents... HSF1 Gel electrophoresis of gene gel recovery products; B is HSF1 Enzyme digestion verification of genes.

[0021] Figure 2 The results show the prokaryotic expression of HSF1 protein. In the figure, A is the SDS-PAGE detection of HSF1 protein induced expression; B is the HSF1 protein solubility analysis; and C is the affinity chromatography purification of HSF1 protein.

[0022] Figure 3 HSF1 protein against PAM CD163CD169 Cell toxicity detection.

[0023] Figure 4 HSF1 protein in PAM CD163CD169Effects of HSF1 protein on TA-12 infection on cells; In the figure, A shows the Western blot results of the effect of HSF1 protein on TA-12 infection; B shows the effect of HSF1 protein on PRRSV replication analyzed by viral titer determination.

[0024] Figure 5 HSF1 protein in PAM CD163CD169 Effects of HSF1 protein on PRRSV life cycle on cells; In the figure, A is the effect of HSF1 protein on PRRSV adsorption; B is the effect of HSF1 protein on PRRSV neutralization; C is the effect of HSF1 protein on PRRSV internalization; D is the effect of HSF1 protein on PRRSV replication; E is the effect of HSF1 protein on PRRSV release.

[0025] Figure 6 HSF1 protein in PAM CD163CD169 Western blot results of the effects of TA-01, TA-02, CH-1R and GZ11-G1 infection on cells.

[0026] Figure 7 Results of viral titer (A, B, C, D) detection on the effect of HSF1 protein on TA-01, TA-02 and CH-1R infections.

[0027] Figure 8 Overexpression HSF1 Effects on PRRSV infection levels; A represents overexpression HSF1 The impact of PRRSV infection levels on Western blot detection results; B represents viral titer overexpression. HSF1 Impact on PRRSV infection. Detailed Implementation

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] As mentioned earlier, PRRSV is highly variable, with variants exhibiting not only alterations in their genomic sequence but also significant differences in virulence and the induced host immune response. Existing anti-PRRSV drugs are unable to simultaneously block infection from different classes of PRRSV variants. Therefore, the high variability of PRRSV poses significant challenges to its clinical prevention and treatment.

[0030] In view of this, this invention, through in-depth research on the PRRSV infection process, has discovered the crucial role of the HSF1 protein in PRRSV infection. Studies have shown that the HSF1 protein can neutralize viral particles, inhibit internalization, replication, and the release of viral particles, and exhibits excellent prevention and control effects against various types of PRRSV variants.

[0031] The amino acid sequence of the HSF1 protein is shown in SEQ ID NO.1, and is as follows: MDLPVGPGAAGPSNVPAFLTKLWTLVSDPDTDALICWSPSGSSFHVLDQGQFAKEVLPKYFKHSNMASFVRQLNMYGFRKVVHIEQGGLVKPERDDTEFQHPCFLRGQEQLLENIKRKVTSVSTLRSED IKIRQDSVTKLLTDVQLMKGKQESMDSKLLAMKHENEALWREVAGLRQKHAQQQKVVNKLIQFLISLVQSNRILGVKRKIPLMLNDASSAHSMPKYGRQYSLEHIHGPGPYTAPAPAYSGPSLYAPDAVA SSGPIISDVTELAPSSPLASPGGSVDEERPLSGSPLVRVKEEPPSPPRSPRAEAAGPGHPSSIVETPLSPTALIDSILRESEPAPTASATLLPDTGGHPPSPLPTSAPEKCLSVACLDKTELSDHLDAMD SNLDNLQTMLSSHGFSVDTSALLDLFSPSVTVPDMNLPDLDSSLASEPPRPLEAESSSPDSGKQLVHYTAQPLLLVDPGSVDVGSSDLPVLFELGEGPYFSEGDDYTDDPTISLLTGSEPPKAKDPTVS.

[0032] HSF1 protein encoding gene HSF1 The nucleotide sequence of the gene is shown in SEQ ID NO.2, as follows:

[0033] To enable those skilled in the art to more clearly understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments. The experimental materials used in the embodiments of this invention are all conventional experimental materials in the art and can be purchased through commercial channels. Wherein: The PRRSV strains used in this invention are represented by strain TA-12 for HP-PRRSV, strain CH-1R for LP-PRRSV, strain TA-01 for NADC30-Like, strain TA-02 for NADC30 recombinant, and strain GZ11-G1 for type 1 PRRSV.

[0034] PAM CD163CD169 The cells used in this invention are porcine alveolar macrophages, a cell line expressing both porcine CD163 and CD169 receptors, commonly used for PRRSV infection, proliferation, receptor mechanism, and antiviral evaluation experiments; the PAM cells used in this invention... CD163CD169 Cells document in the journal A porcine reproductive and respiratory syndrome virus (PRRSV)-specific IgM as a novel adjuvant for an inactivated PRRSV vaccine improves protection efficiency and enhances cell-mediated immunity against heterologous PRRSV challenge. Veterinary Research (2022, 53:65.); the name in that literature is "CRL-2843 CD163 / CD169 cells".

[0035] All of the above-mentioned biological materials are known in the prior art, and the public may obtain the above-mentioned strains from the applicant within 20 years from the date of application to use for replicating the present invention.

[0036] The maintenance medium used in this invention is DMEM medium (2% FBS-DMEM) containing 2% (v / v) fetal bovine serum.

[0037] Example 1: Prokaryotic expression of HSF1 protein According to the NCBI HSF1 The gene sequence (GenBank accession number NM_001243819.1) was obtained, and HSF1 cloning primers were designed (see Table 1).

[0038] Table 1: HSF1 cloning primers The Trizol method was used to extract PAM-derived components. CD163CD169 Cellular RNA was reverse transcribed into cDNA, which served as a template for amplifying the HSF1 gene. The primer pairs (pET-28a-HSF1-F, pET-28a-HSF1-R) in Table 1 were then used for amplification. HSF1 Gene amplification. The amplified gene was then recovered using a gel electrophoresis, and the results are as follows: Figure 1 As shown in Figure A; the target gene was ligated into the pET-28a vector, and then transformed into DH5α E. coli competent cells. Subsequent verification was performed by bacterial PCR and enzyme digestion. The enzyme digestion results are shown in Figure A. Figure 1 As shown in B.

[0039] The validated HSF1 plasmid was transformed into E. coli BL21 competent cells. After IPTG induction, expression was detected by SDS-PAGE, and the results showed that the recombinant HSF1 protein was successfully expressed. Figure 2 (A). Further analysis of the solubility of HSF1 was conducted. After ultrasonic disruption of the bacterial cells, the supernatant and inclusion bodies were separated. The results showed that HSF1 protein was mainly found in the inclusion bodies. Figure 2 (B) Affinity chromatography was used to purify HSF1 protein. The results showed that the eluted fraction contained a single, clear target band with high purity. Figure 2 The presence of SEQ ID NO. 1 indicates that high-purity HSF1 protein was successfully obtained. The obtained HSF1 protein was sequenced for verification, and its amino acid sequence is shown in SEQ ID NO. 1.

[0040] Example 2: HSF1 protein in PAM CD163CD169 Inhibition of TA-12 infection on cells 1. Safety concentration test: The HSF1 protein prepared in Example 1 was prepared into protein solutions of 0, 10, 20, 40, 80, 120, and 150 μg / mL using maintenance solution (2% FBS-DMEM). The effects of different concentrations of HSF1 protein treatment on PAM were detected using the CCK-8 assay. CD163CD169 The impact on cell viability.

[0041] The results are as follows Figure 3 As shown, when the concentration of HSF1 protein is in the range of 0~40 μg / mL, the cell viability is maintained above 95%.

[0042] 2. Verify its effect on PRRSV replication using safe concentrations: Based on the results of the study using safe concentrations, three concentrations of HSF1 protein (10, 20, and 40 μg / mL) were selected to verify its effect on PRRSV; a maintenance solution (0 μg / mL) without HSF1 protein was used as a control.

[0043] PAM CD163CD169 Cells were infected with TA-12. Two hours after infection, the medium was replaced with a maintenance medium containing the corresponding concentration of HSF1 protein. After 30 hours of culture, cells and supernatant were collected, and the viral titer and the expression level of PRRSV N protein (PRRSV-N) were detected.

[0044] The results are as follows Figure 4 As shown, HSF1 protein treatment resulted in a dose-dependent decrease in the expression level of PRRSV N protein; viral titer also decreased in a dose-dependent manner. These results indicate that HSF1 protein can effectively inhibit TA-12 replication, thereby suppressing TA-12 infection.

[0045] Example 3: HSF1 protein in PAM CD163CD169 Experiment on the effect of TA-12 infection on cells 1. Effect on PRRSV adsorption: First use PAM CD163CD169 Cells were seeded into monolayers and the original culture medium was discarded. Cells were washed twice with PBS. The experimental group was treated with maintenance medium containing 30 μg / mL HSF1 protein, while the control group was treated with an equal volume of maintenance medium without HSF1. Pretreatment was performed at 37°C for 4 h. After pretreatment, PRRSV TA-12 strain was inoculated at an MOI of 0.1 and incubated at 4°C for 2 h for adsorption. During adsorption, the culture plate was gently shaken every 30 min to ensure even virus distribution. After adsorption, cells were washed three times with pre-cooled PBS to remove unadsorbed virus particles. Cells were collected, and total RNA was extracted using the TRIzol method. cDNA was reverse transcribed, and the viral N protein gene copy number was detected by qPCR (primers used for quantitative real-time PCR are shown in Table 2).

[0046] Table 2: Primers used for quantitative fluorescence detection qPCR results showed that 30 μg / mL HSF1 protein inhibited HP-PRRSV in PAM CD163CD169 Adsorption on cells had no significant effect. Figure 5 (A)

[0047] 2. Effects on PRRSV neutralization PRRSV TA-12 was diluted with pure DMEM, and 30 μg / mL of HSF1 protein was added and mixed thoroughly. A control group without protein was also included. The virus-protein mixture or virus-only solution was added to PMEM according to the cell inoculation method.CD163CD169 Cells were adsorbed at 4°C for 2 h. After adsorption, the cells were washed twice with pre-cooled PBS to thoroughly remove unadsorbed viral particles. Cells were collected, total RNA was extracted using the TRIzol method, cDNA was synthesized by reverse transcription, and the viral N protein gene copy number was detected by qPCR to assess the neutralizing activity of HSF1 protein against PRRSV. (Primers used for real-time PCR are shown in Table 2.)

[0048] qPCR results showed that 30 μg / mL HSF1 protein had neutralizing activity against PRRSV viral particles. Figure 5 (B)

[0049] 3. Impact on the PRRSV internalization stage: PAM CD163CD169 Cells were infected with TA-12 at MOI=0.1 and incubated at 4℃ for 2 h. Then, 30 μg / mL HSF1 protein was added, and the cells were transferred to a 37℃ incubator for 4 h. After washing with PBS buffer at pH=2.5, RNA was extracted from the cells and reverse transcribed into cDNA. The results were verified by quantitative real-time PCR (primers used for quantitative real-time PCR are shown in Table 2) to detect internalized PRRSV particles and determine the effect of HSF1 protein on the PRRSV internalization stage.

[0050] qPCR results showed that 30 μg / mL HSF1 protein could reduce HP-PRRSV in PAM CD163CD169 Internalization on cells ( Figure 5 (C)

[0051] 4. Effects on PRRSV intracellular replication: PAM CD163CD169 Cells were infected with TA-12 at an MOI of 0.1 and incubated at 37°C for 6 h. After washing twice with PBS buffer, 30 μg / mL HSF1 protein was added and the cells were transferred to a 37°C incubator. Cells were collected at 6, 10, 15, 20, and 25 h post-infection to extract RNA, which was then reverse transcribed and verified by quantitative real-time PCR (primers used for quantitative real-time PCR are shown in Table 2) to detect viral copy number and determine the effect of HSF1 protein on PRRSV replication in cells.

[0052] qPCR results showed that 30 μg / mL HSF1 protein could reduce HP-PRRSV in PAM CD163CD169 Intracellular replication process ( Figure 5 (D).

[0053] 5. Effects on PRRSV release: PAM CD163CD169Cells were infected with TA-12 at an MOI of 0.1 and incubated at 37°C for 8 h. After washing three times with PBS buffer, 30 μg / mL HSF1 protein was added and the cells were transferred to a 37°C incubator. Cell supernatants were collected and viral titers were measured at 12, 18, and 24 h after infection to detect PRRSV particles released in the cell supernatant and determine the effect of HSF1 protein on the PRRSV viral particle release phase.

[0054] TCID 50 The results showed that 30 μg / mL HSF1 protein could reduce HP-PRRSV in PAM CD163CD169 Viral particles released from cells ( Figure 5 (E).

[0055] Example 4: HSF1 protein in PAM CD163CD169 Inhibition experiments on TA-01, TA-02, CH-1R and GZ11-G1 infection in cells In single-layer PAM CD163CD169 Cells were inoculated with TA-01, TA-02, CH-1R, and GZ11-G1 strains at an MOI of 0.05. Two hours post-infection, the cells were replaced with maintenance media containing 0 or 30 μg / mL HSF1 protein, respectively. Thirty hours after infection, cells and supernatant were collected. Cells were washed with pre-cooled PBS, pipetteed, and transferred to new centrifuge tubes. The supernatant was discarded after centrifugation, and the precipitate was retained. Protein was collected for Western blot analysis, and viral titer was determined using the cell supernatant to assess the effect of HSF1 protein on infection with different PRRSV strains.

[0056] Western blot results showed that HSF1 protein significantly inhibited the activity of different strains in PAM. CD163CD169 Infection on cells ( Figure 6 Virus titer assays also showed that HSF1 protein can reduce infection rates in different strains. Figure 7 ).

[0057] Example 5: Overexpression HSF1 Experiment on the effect of genes on PRRSV infection levels Using the primer pairs (pCMV-HA-N-HSF1(Swine)-F, pCMV-HA-N-HSF1(Swine)-R) in Table 1, HSF1 Gene amplification was performed, and the amplified fragment was ligated into the eukaryotic expression vector pCMV-HA-N to construct a gene containing... HSF1 The eukaryotic expression plasmid of the gene (pCMV-HA-N-HSF1).

[0058] PAMCD163CD169 Cells at 2.5 × 10 5 Cells were seeded at a density of 1:1 ratio in six-well plates and cultured at 37°C in a 5% CO2 incubator for 24 h. 2 μg of the pCMV-HA-N-HSF1 eukaryotic expression plasmid was transfected into the cells, with a control group transfected with an empty vector. Cultures were continued for another 24 h. HP-PRRSV TA-12 strain was inoculated at an MOI of 0.1, and after adsorption at 37°C for 1 h, the viral load was discarded. Cells were washed twice with PBS and cultured in maintenance medium. Cell samples and culture supernatants were collected 30 h after PRRSV inoculation. Total protein was extracted from the cell samples using RIPA lysis buffer. Western blot analysis was performed to detect the expression levels of PRRSV N protein and HA-HSF1, using GAPDH as an internal control. Viral titers were determined after 10-fold serial dilutions of the cell culture supernatant.

[0059] The results show that in PAM CD163CD169 Overexpression of HSF1 on cells can significantly reduce the expression level of PRRSV-N protein. Figure 8 (A); Viral titer assay results further confirmed that HSF1 overexpression significantly reduced the viral titer in the cell supernatant ( Figure 8 (B)

[0060] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. The application of HSF1 protein in the preparation of drugs that inhibit PRRSV infection, characterized in that, The HSF1 protein is the protein shown in either (A1) or (A2) below: (A1) A protein consisting of the amino acid sequence shown in SEQ ID NO.1 of the sequence listing; (A2) A fusion protein obtained by attaching a protein tag to the N-terminus and / or C-terminus of the protein defined in (A1).

2. The application according to claim 1, characterized in that, The HSF1 protein inhibits PRRSV infection through at least one of the following pathways (1)-(4): (1) Neutralize PRRSV viral particles; (2) Interferes with the internalization process of PRRSV entering the host cell; (3) Inhibit PRRSV genome replication in host cells; (4) It hinders the assembly and release of PRRSV progeny virus particles.

3. The application according to claim 1, characterized in that, The PRRSV type is at least one of HP-PRRSV, NADC30-like, NADC30, LP-PRRSV, and type 1 PRRSV.

4. The application according to claim 1, characterized in that, The effective concentration of HSF1 protein in the drug is 10-40 μg / mL.

5. The application according to claim 4, characterized in that, The drug also contains veterinary pharmaceutically acceptable excipients, including: One or more of the following: stabilizers, preservatives, isotonic adjusters, pH buffers, surfactants, thickeners, and antioxidants.

6. The application according to claim 1, characterized in that, The dosage form of the drug is lyophilized powder for injection, aqueous injection, oral solution, nasal spray, or feed premix.

7. The application of the HSF1 protein encoding gene in the preparation of drugs to inhibit PRRSV infection, characterized in that, The gene encoding the HSF1 protein is a nucleic acid molecule as shown in i) or ii) below: i) The nucleotide sequence is the nucleic acid molecule shown in SEQ ID NO.2; ii) Nucleic acid molecules other than those in i) that encode the amino acid sequence shown in SEQ ID NO.

1.

8. The application according to claim 7, characterized in that, PRRSV infection can be suppressed by promoting the expression of the gene encoding the HSF1 protein.

9. The application according to claim 8, characterized in that, The substance that promotes the expression of the gene encoding the HSF1 protein is any one of the following: C1) Expression cassette containing the gene encoding the HSF1 protein; C2) A recombinant vector containing the gene encoding the HSF1 protein, or a recombinant vector containing the expression cassette described in C1); C3) Recombinant microorganisms containing the gene encoding the HSF1 protein, or recombinant microorganisms containing the expression cassette described in C1), or recombinant microorganisms containing the recombinant vector described in C2).

10. The application according to claim 7, characterized in that, The PRRSV type is at least one of HP-PRRSV, NADC30-like, NADC30, LP-PRRSV, and type 1 PRRSV.

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