Feline panleucopenia virus 708 strain and application thereof

Abstract

The invention relates to the field of veterinary biological products, in particular to a feline panleukopenia virus and application thereof. The preservation number of the feline panleucopenia virus 708 strain is CCTCC No.V202320, and the feline panleucopenia virus 708 strain belongs to existing epidemic strains, has good immunogenicity and can provide effective immune protection for epidemic strains in different regions.

Description

Technical Field

[0001] The present application relates to the field of veterinary biological products, and in particular to feline panleukopenia virus and its application. Background Art

[0002] Feline panleukopenia is an acute, highly contagious disease caused by the feline panleukopenia virus (FPV), which mainly harms cats, raccoons and mustelids. Feline panleukopenia is mainly characterized by leukopenia, loss of appetite, vomiting, diarrhea, fever, etc. In 1984, FPV was isolated from a naturally infected case in my country for the first time, thus confirming the prevalence of the virus in my country, posing a great threat to cats, felines and wild animals. The disease is the most common disease in kittens after weaning and when maternal antibodies are reduced. Cats of different breeds and ages are susceptible, and the incidence is closely related to the cat's own immune status, with an infection rate of up to 70%.

[0003] At present, vaccination is the main means of preventing the disease. Although the virus gene is relatively stable, after a long period of epidemic, the epidemic strains in different regions still have significant variations, which leads to the phenomenon of occasional disease after vaccination. Therefore, it is urgent to screen out strains that have immune protection against epidemic strains in different regions, which is of great significance for the prevention and control of feline panleukopenia.

[0004] In view of this, this application is hereby filed. Application Contents

[0005] The purpose of the present application is to provide a feline panleukopenia virus strain, which belongs to the existing epidemic strain and has good immunogenicity and can provide effective immune protection against epidemic strains in different regions.

[0006] In order to achieve the above purpose, this application adopts the following technical solutions:

[0007] Feline panleukopenia virus strain 708, the deposit number is CCTCC No.V202320.

[0008] Application of feline panleukopenia virus strain 708 in the preparation of drugs for preventing diseases related to feline panleukopenia virus infection.

[0009] Furthermore, the drug is an inactivated feline panleukopenia virus vaccine.

[0010] A vaccine composition comprises an immunizing amount of a feline panleukopenia virus 708 strain antigen and a pharmaceutically acceptable carrier.

[0011] Furthermore, the antigen is 1 to 15 generations of feline panleukopenia virus 708 strain or its culture.

[0012] Furthermore, the antigen is the inactivated 1 to 15 generation feline panleukopenia virus 708 strain or its culture, preferably, the antigen content is 10 5.0 ~10 6.0 FAID 50 / ml, preferably 10 6.0 FAID 50 / ml.

[0013] Furthermore, the pharmaceutically acceptable carrier includes an adjuvant, and the adjuvant includes one or more of aluminum gel adjuvant, saponin, avridine, DDA, oil-in-water emulsion, water-in-oil emulsion, water-in-oil-in-water emulsion, polymer of acrylic acid or methacrylic acid, copolymer of maleic anhydride and alkenyl derivative, RIBI adjuvant system, Block co-polymer, SAF-M, monophosphoryl lipid A, Avridine lipid-amine adjuvant, Escherichia coli heat-labile enterotoxin, cholera toxin, IMS1314, muramyl dipeptide, and Gel adjuvant.

[0014] Furthermore, the concentration of the adjuvant ranges from 5% V / V to 50% V / V, preferably 10% V / V.

[0015] A method for preparing a vaccine composition comprises culturing and proliferating the feline panleukopenia virus 708 strain, inactivating the proliferated feline panleukopenia virus 708 strain or its culture, and adding a pharmaceutically acceptable carrier to the inactivated feline panleukopenia virus 708 strain or its culture.

[0016] Furthermore, the inactivation is inactivation with an inactivating agent.

[0017] Compared with the prior art, the technical effects of this application are:

[0018] The feline panleukopenia virus strain isolated in the present application is genetically a prevalent wild strain of feline panleukopenia virus. Immunizing animals with a vaccine composition containing the strain can enable the animal body to quickly produce high titer specific antibodies, which can effectively prevent epidemics caused by feline panleukopenia virus and provide effective immune protection against prevalent strains in different regions. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present application will be described.

[0020] The term "feline panleukopenia virus" (FPV) belongs to the genus Parvovirus of the family Parvoviridae. The clinical symptoms it causes are mostly characterized by sudden high fever, persistent vomiting, diarrhea, dehydration, circulatory disorders and leukopenia.

[0021] The term "feline panleukopenia virus strain (FPV strain)" in this application, unless otherwise specified, refers to the wild-type feline panleukopenia virus strain (FPV wild-type strain), the virulent feline panleukopenia virus strain (FPV virulent strain), and the wild-type FPV strain, and can be used interchangeably.

[0022] The present application relates to Feline Panleukopenia Virus 708 strain, with a deposit number of CCTCC No. V202320. Feline PanleukoPenia Virus 708 strain (Feline PanleukoPenia virus, Strain 708) is deposited in China Center for Type Culture Collection, with a deposit number of CCTCC NO: V202320, and a deposit address of Wuhan University, Wuhan, China, with a deposit date of March 21, 2023.

[0023] The feline panleukopenia virus strain 708 is genetically a prevalent wild strain of feline panleukopenia virus. Immunizing animals with a vaccine composition containing the strain can rapidly produce high titer specific antibodies in the animal body, effectively preventing epidemics caused by feline panleukopenia virus, and providing effective immune protection against prevalent strains in different regions. Therefore, the present application provides the use of the feline panleukopenia virus strain 708 in the preparation of a drug for preventing diseases related to feline panleukopenia virus infection.

[0024] In some embodiments, the medicament is an inactivated feline panleukopenia virus vaccine.

[0025] The present application relates to a vaccine composition, wherein the vaccine composition comprises an immunizing amount of an antigen of the feline panleukopenia virus strain 708 and a pharmaceutically acceptable carrier.

[0026] In some embodiments, the antigen can be 1-15 passages of feline panleukopenia virus 708 strains, or 1-15 passages of feline panleukopenia virus 708 strain cultures. Preferably, 1-15 passages of feline panleukopenia virus 708 strains or cultures thereof are inactivated or attenuated.

[0027] The term "vaccine composition", also known as an immunogenic composition, refers to a preparation containing an immunogen, including, for example, whole cells, inactivated or attenuated, live viruses or bacteria, or polysaccharides, or a combination thereof, which is administered to stimulate a humoral and cellular immune response in a recipient to one or more antigens present in the immunogenic composition. Immunization is the process of administering a vaccine composition and stimulating an immune or immunogenic response to the antigen in a host, preferably an animal such as a cat.

[0028] The term "immunizing amount" should be understood as an "immunologically effective amount", also known as an immunoprotective amount or an effective amount for producing an immune response, which is an amount of antigen that can effectively induce an immune response in the recipient, and this amount is sufficient to prevent or improve the signs or symptoms of the disease, including adverse health effects or its complications. The immune response may be sufficient for diagnostic purposes or other tests, or may be suitable for preventing signs or symptoms of the disease, including adverse health consequences or complications caused by infections caused by pathogens. Humoral immunity or cell-mediated immunity or both can be induced. The immune response of animals to the immunogenic composition can be indirectly assessed by, for example, measuring antibody titers, lymphocyte proliferation analysis, or directly assessed by monitoring signs or symptoms after attacking with wild-type strains, and the protective immunity provided by the vaccine can be assessed by measuring, for example, clinical signs of the subject such as mortality, reduction in morbidity, temperature values, overall physiological condition of the subject, and overall health and performance. The immune response may include, but is not limited to, inducing cellular and / or humoral immunity.

[0029] The term "antigen of feline panleukopenia virus" refers to any composition containing at least one form of feline panleukopenia virus antigen, which can induce, stimulate or resist an immune response to feline panleukopenia virus infection, including but not limited to inactivated, attenuated or subunit antigens. Wherein, the inactivated antigen can be inactivated by various methods including chemical treatment, physical treatment (such as sonication, irradiation, heat) or any other common method sufficient to prevent the replication or growth of the organism to maintain its immunogenicity, preferably the pathogen is inactivated after collection and optionally subjected to clarification and purification, such as formalin or formaldehyde, β-propiolactone, ethyleneimine, diethyleneimine BEI, thimerosal, etc., by chemical treatment; the method of inactivation is well known to those skilled in the art, such as by β-propiolactone (Plana-Duran et al., Vet. Microbiol., 1997, 55: 361-370) or by BEI treatment (US5587164).

[0030] As an embodiment of the present application, in the vaccine composition described in the present application, the antigen is an inactivated 1 to 15 generation feline panleukopenia virus 708 strain or a culture thereof, and the antigen content is 105.0 ~10 6.0 FAID 50 / ml.

[0031] As a preferred embodiment of the present application, the inactivated whole virus antigen content of the feline panleukopenia virus 708 strain or its culture is 10 5.5 FAID 50 / ml.

[0032] As a preferred embodiment of the present application, the inactivated whole virus antigen content of the feline panleukopenia virus 708 strain or its culture is 10 6.0 FAID 50 / ml.

[0033] The inactivated whole virus antigen content of feline panleukopenia virus 708 strain or its culture can be selected from the 10 5.0 FAID 50 / ml, 10 5.1 FAID 50 / ml, 10 5.2 FAID 50 / ml, 10 5.3 FAID 50 / ml, 10 5.4 FAID 50 / ml, 10 5.5 FAID 50 / ml, 10 5.6 FAID 50 / ml, 10 5.7 FAID 50 / ml, 10 5.8 FAID 50 / ml, 10 5.9 FAID 50 / ml, 10 6.0 FAID 50 / ml.

[0034] The term "1-15th generation feline panleukopenia virus 708 strain culture" refers to the culture obtained by continuously and naturally passaging the feline panleukopenia virus 708 strain on F81 cells, causing it to adapt to growth and replication on F81 cells (i.e., the appearance of stringy cytopathic effects on the cells), and then continuing to naturally passage on F81 cells to the 1st to 15th generations.

[0035] The term "pharmaceutically acceptable carrier" refers to all other ingredients in the vaccine composition of the present application except the feline panleukopenia virus antigen, a carrier or diluent that does not stimulate the body and does not hinder the biological activity and characteristics of the compound used, preferably an adjuvant. The term "adjuvant" may include aluminum gel adjuvants; saponins (saponin), such as Quil A, QS-21 (Cambridge Biotech Incorporation, Cambridge MA), GPI-0100 (Galenica Pharmaceuticals Incorporation, Birmingham AL); oil-in-water emulsions; water-in-oil emulsions such as the SPT emulsion described on page 147 and the MF59 emulsion described on page 183 of "Vaccine design, the Subunit and adiuvant approach" (Plenum Press, 1995) written by Powell M and Newman M; water-in-oil-in-water emulsions; polymers of acrylic acid or methacrylic acid; one or more copolymers of maleic anhydride and alkenyl derivatives. The term "emulsion" may be based in particular on light liquid paraffin oil (European Pharmacopea type); isoprenoid oils resulting from olefin oligomerization, such as squalane or squalene oil, especially isobutylene or decene; linear alkyl-containing esters of acids or alcohols, more particularly vegetable oils, ethyl oleate, propylene glycol di-(caprylate / decene), glycerol tri-(caprylate / decene) or propylene glycol dioleate; esters of branched fatty acids or alcohols, especially isostearates. The oil is used in combination with an emulsifier to form an emulsion. Emulsifiers are preferably nonionic surfactants, especially esters of sorbitan, esters of mannide (such as anhydrous mannitol oleate), esters of fatty glycols, esters of polyglycerols, esters of propylene glycol, and esters of oleic acid, isostearic acid, ricinoleic acid or hydroxystearic acid, which are optionally ethoxylated, and polyoxypropylene-polyoxyethylene block copolymers, especially Pluronic products, in particular L121. See Hunter et al., The theory and practical application of adjuvants (Ed. by DES Stewart-Tull, John Wiley and Sons, New York, 1995: 51-94) and Todd et al., Vaccine (1997, 15: 564-570).The term "polymer of acrylic acid or methacrylic acid" is preferably a cross-linked acrylic acid or methacrylic acid polymer, especially cross-linked with a polyalkenyl ether of sugar or a polyol, such compounds being known as carbomers (Carbopol, trade name) (Phameuropa, 1996, 8 (2)). Those skilled in the art may also refer to U.S. Pat. No. 2,909,462, which describes such acrylic acid polymers cross-linked with polyhydroxylated compounds having at least 3 hydroxyl groups, preferably not more than 8, wherein the hydrogen atoms of at least 3 hydroxyl groups are replaced by unsaturated aliphatic radicals having at least 2 carbon atoms. Preferred groups are those containing 2-4 carbon atoms, such as vinyl, allyl and other ethylenically unsaturated groups. The unsaturated groups themselves may contain other substituents, such as methyl. The products sold under the name of EMA (BF Goodrich, Ohio, USA) are particularly suitable. They are crosslinked with allyl sucrose or with allyl pentaerythritol. Among these, mention may be made of carbomers 974P, 934P and 971P, with carbomer 971P being most preferably used. The term "copolymers of maleic anhydride and alkenyl derivatives" also considers copolymers of maleic anhydride with ethylene EMA (Monsanto), these polymers dissolving in water to give an acidic solution, which is neutralized, preferably to physiological pH, in order to give an adjuvant solution into which the immunogenic, immunogenic or vaccinia composition itself can be incorporated. The term "adjuvant" also includes, but is not limited to, RIBI adjuvant system (Ribi Incorporation), Block co-polymer (CytRx, Atlanta GA), SAF-M (Chiron, Emeryville CA), monophosphoryl lipid A, Avridine lipid-amine adjuvant, Escherichia coli heat-labile enterotoxin (recombinant or other), cholera toxin, IMS1314, muramyl dipeptide, Gel adjuvant, etc. Preferably, the adjuvant includes one or more of aluminum gel adjuvant, saponin, water-in-oil emulsion, oil-in-water emulsion, water-in-oil-in-water emulsion, polymer of acrylic acid or methacrylic acid, copolymer of maleic anhydride and alkenyl derivative, RIBI adjuvant system, Block co-polymer, SAF-M, monophosphoryl lipid A, Avridine lipid-amine adjuvant, Escherichia coli heat-labile enterotoxin, cholera toxin, IMS1314, muramyl dipeptide or Gel adjuvant.

[0036] As one embodiment of the present application, in the vaccine composition described in the present application, the pharmaceutically acceptable carrier includes an adjuvant, and the adjuvant includes: (1) aluminum gel adjuvant, saponin, avridine, DDA; (2) water-in-oil emulsion, oil-in-water emulsion, water-in-oil-in-water emulsion; or (3) polymers of acrylic acid or methacrylic acid, copolymers of maleic anhydride and alkenyl derivatives; and one or more of RIBI adjuvant system, Block co-polymer, SAF-M, monophosphoryl lipid A, Avridine lipid-amine adjuvant, Escherichia coli heat-labile enterotoxin, cholera toxin, IMS1314, muramyl dipeptide, and Gel adjuvant.

[0037] Preferably, the saponin is Quil A, QS-21, GPI-0100.

[0038] Preferably, the emulsion is an SPT emulsion, an MF59 emulsion, or an emulsion formed by combining an oil with an emulsifier, and the emulsion can be based on light liquid paraffin oil, isoprenoid oils produced by olefin oligomerization (such as squalane or squalene oil, olefins, especially oils produced by oligomerization of isobutylene or decene), linear alkyl-containing esters of acids or alcohols (more especially vegetable oils, ethyl oleate, propylene glycol di-(caprylate / caprylate), glycerol tri-(caprylate / caprylate) or propylene glycol dioleate), esters of branched fatty acids or alcohols ( emulsifiers are nonionic surfactants (especially esters of polyoxyethylated fatty acids (e.g. oleic acid), esters of sorbitan, esters of mannide (e.g. anhydrous mannitol oleate), esters of aliphatic diols, esters of glycerol, esters of polyglycerol, esters of propylene glycol, and esters of oleic acid, esters of isostearic acid, esters of ricinoleic acid or esters of hydroxystearic acid, which esters may be ethoxylated, ethers of fatty alcohols and polyols (e.g. oleyl alcohol), polyoxypropylene-polyoxyethylene block copolymers (especially Especially L121)).

[0039] Preferably, the polymer of acrylic acid or methacrylic acid is a cross-linked acrylic acid or methacrylic acid polymer, especially a compound carbomer cross-linked with a polyalkenyl ether of a sugar or a polyalcohol, preferably carbomer 974P, 934P and 971P.

[0040] Preferably, the copolymer of maleic anhydride and an alkenyl derivative is a copolymer of maleic anhydride and ethylene EMA.

[0041] Preferably, the adjuvant is Gel A adjuvant.

[0042] The concentration of the adjuvant ranges from 5% to 50% V / V, preferably 10% V / V.

[0043] The present application also relates to a method for preparing the vaccine composition, which comprises: culturing and proliferating the feline panleukopenia virus 708 strain, inactivating the proliferated feline panleukopenia virus 708 strain or its culture, and adding a pharmaceutically acceptable carrier to the inactivated feline panleukopenia virus 708 strain or its culture.

[0044] As an implementation manner of the present application, the inactivation is inactivation with an inactivating agent.

[0045] As an embodiment of the present application, the inactivator includes but is not limited to β-propiolactone BPL, diethyleneimine BEI, formalin, formaldehyde, N-acetylenimine AEI, and polyhexamethyleneguanidine hydrochloride PHMG; preferably, the inactivator is β-propiolactone BPL, and its final concentration in the vaccine composition is 0.05% V / V to 0.1% V / V.

[0046] The term "prevent" when referring to feline panleukopenia virus infection means inhibiting the replication of feline panleukopenia virus, inhibiting the spread of feline panleukopenia virus, or preventing feline panleukopenia virus from establishing in its host, as well as alleviating the symptoms of a disease or condition caused by feline panleukopenia virus infection.

[0047] The present application also relates to the use of the vaccine composition in the preparation of a drug for preventing diseases associated with feline panleukopenia virus infection.

[0048] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0049] Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0050] Example 1 Isolation and Identification of Feline Panleukopenia Virus

[0051] Anal swabs and intestinal content samples of cats suspected of being infected with feline panleukopenia virus were collected from multiple pet hospitals in Liaoning, Henan, Zhejiang, Guangdong and other places. 87 samples were found to be infected with feline panleukopenia virus by PCR. The collected anal swabs and intestinal content samples were diluted 10 times with PBS, centrifuged at 5000 rpm for 10 minutes, and the supernatant was filtered with a 0.22μm filter and inoculated into cat kidney cells (F81 cells). The cytopathic effect was observed daily, and the culture was repeatedly frozen and thawed at -70℃ and inoculated into F81 cells. The virus was collected by blind transmission in the same way until cytopathic effect was produced. The results showed that the cytopathic effect of 82 samples after inoculation was not obvious or the lesions were lost during the passage process. Only 5 samples could produce obvious cytopathic effect after inoculation, and further sequence comparison was performed by molecular biological methods, confirming that they were all feline panleukopenia virus, and the 5 strains of viruses were numbered 020, 021, 707, 708, and 602 respectively.

[0052] Example 2 Pathogenicity Study of Feline Panleukopenia Virus

[0053] Thirty healthy susceptible antigen antibody-negative cats aged 2 months were randomly divided into 6 groups, with 5 cats in each group. The grouping and infection situation are shown in Table 1.

[0054] Table 1 Pathogenicity study groups Group Inoculation strain Vaccination dose 1 020 strains <![CDATA[Each was inoculated with 4 ml (10 5.5 FAID 50 / ml)]]> 2 021 strains <![CDATA[Each was inoculated with 4 ml (10 5.5 FAID 50 / ml)]]> 3 707 strains <![CDATA[Each was inoculated with 4 ml (10 5.5 FAID 50 / ml)]]> 4 708 strains <![CDATA[Each was inoculated with 4 ml (10 5.5 FAID 50 / ml)]]> 5 602 strains <![CDATA[Each was inoculated with 4 ml (10 5.5 FAID 50 / ml)]]> 6 RPMI1640 medium 4 ml per inoculation

[0055] The cats were observed for 10 days after virus inoculation. The cats' body temperature, appetite, feces and other clinical manifestations were observed and recorded daily, and the peripheral blood leukocyte count was measured regularly. The specific results are shown in Table 2.

[0056] Table 2 Pathogenicity study results

[0057] The results showed that all five strains of FPV could cause 100% disease in cats (5 / 5), with FPV 708 being the most pathogenic (5 / 5 deaths).

[0058] At the same time, in order to verify the stability of the pathogenicity of different generations of feline panleukopenia virus 708 strain, a group of cats (5) with feline panleukopenia virus antigen-antibody negative were inoculated with 4 ml (10 5.5 FAID 50 / ml), and 5 cats were used as the control group. The clinical changes of the cats were observed and recorded daily, and the number of peripheral blood leukocytes was measured regularly until 10 days after inoculation.

[0059] The results showed that 100% of the 5th, 7th, 10th and 15th generations of feline panleukopenia virus 708 strain cultures developed disease (5 / 5) after 10 days of observation after inoculation, indicating that the pathogenicity of feline panleukopenia virus 708 strains at different generations is stable.

[0060] Example 3 Preparation of Feline Panleukopenia Virus 708 Strain Antigen

[0061] Cell recovery: F81 cells were taken out of the liquid nitrogen tank, shaken in a 37°C water bath to melt, and then transferred to a 50ml centrifuge tube. 15ml of culture medium was added dropwise, and the cells were centrifuged at 115g for 5min in a horizontal rotor centrifuge. The supernatant was discarded, and the cells were resuspended in 20ml of culture medium. The cells were transferred to a 125ml shake flask and cultured in a shaker containing 5% carbon dioxide.

[0062] Cell passaging: 1.5×10 6 cells / ml initial density, culture volume 30ml, inoculated into 125ml shake flask. Placed in a shaker at 37℃, 5% carbon dioxide concentration, orbit radius 25mm, speed 120rpm, humidity 80%. Cultured until the third day, according to 1.5×10 6 cells / ml and gradually increase the cell seed amount to prepare seed cells for the 3L reactor.

[0063] Virus proliferation in 3L reactor: Adjust the initial cell density in the 3L reactor to 2.0×10 6 cells / m, the culture volume is 1L, MOI=0.005-0.5, and the feline panleukopenia virus 708 strain virus is inoculated. The parameter settings are: temperature 37°C, pH 7.2±0.2, dissolved oxygen 40%-60%, associated stirring speed 100-150rpm, oxygen 0-0.1vvm, air 0.075vvm, surface ventilation (ventilation and oxygen supply from the surface) 0.05vvm. The cells are harvested when the cell viability drops below 90%. The harvested virus liquid is filtered by centrifugation or hollow fiber (0.5μm-2μm) filter column to remove cell debris, and then an inactivator is added for inactivation. The virus antigen after complete inactivation is used to prepare a vaccine.

[0064] Example 4 Preparation of Feline Panleukopenia Virus 708 Strain Vaccine Composition

[0065] The inactivated antigen of feline panleukopenia virus strain 708 prepared in Example 3 is slowly added to the adjuvant, and stirring is continuously used during the addition process to mix. The adjuvant suitable for this application can be an adjuvant known to those skilled in the art. In this application, the adjuvant is a high molecular polymer water-soluble adjuvant, for example, it can be carbomer. The specific formula of the vaccine is shown in Table 3.

[0066] Table 3 Feline panleukopenia virus 708 strain vaccine ratio

[0067] Example 5 Immunogenicity Test of Feline Panleukopenia Virus 708 Strain Vaccine Composition

[0068] Twenty healthy susceptible antigen antibody negative cats aged 2 months were randomly divided into 4 groups, 5 in each group. Groups 7 to 9 were subcutaneously inoculated with 1 ml of inactivated vaccine 1, 2, and 3, respectively, and group 10 was subcutaneously injected with 1 ml of normal saline as a blank control. 21 days after immunization, the test cats were challenged with feline panleukopenia virus strain 708. Each cat was inoculated with 4 ml (10 5.5 FAID 50 / ml), and the body temperature, appetite, feces and other clinical manifestations of the cats were observed and recorded every day after the infection, and the peripheral blood leukocyte count was measured regularly. The specific results are shown in Table 4.

[0069] Table 4 Results of immunogenicity test of feline panleukopenia virus 708 strain vaccine composition

[0070] The results showed that all cats vaccinated with the feline panleukopenia virus 708 strain vaccine composition were protected, while all cats in the control group became ill and died.

[0071] The immunogenicity test showed that the feline panleukopenia virus 708 strain had good immunogenicity and could provide good protection against the virulent attack of feline panleukopenia virus.

[0072] At the same time, in order to verify the stability of immunogenicity of different generations of feline panleukopenia virus 708, each immunized group and the control group were inoculated with 4 ml (10 5.5 FAID 50 / ml) dose of the cats were challenged with the virus. After the challenge, the cats' body temperature, appetite, feces and other clinical manifestations were observed and recorded every day, and the peripheral blood leukocyte count was measured regularly.

[0073] The results showed that all cats inoculated with the 5th, 7th, 10th and 15th generations of feline panleukopenia virus 708 strain cultures were protected, while all cats in the control group became ill and died.

[0074] The immunogenicity tests of different generations showed that cultures of different generations of feline panleukopenia virus 708 strain all had good immunogenicity and could provide good protection against the virulent attack of feline panleukopenia virus.

[0075] Example 6 Feline Panleukopenia Virus 708 Strain Vaccine Composition Immunity Duration Test

[0076] Twenty healthy susceptible antigen antibody negative cats aged 2 months were randomly divided into 4 groups, 5 in each group. Groups 11 to 13 were vaccinated with inactivated vaccine 1, vaccine 2 and vaccine 3, respectively, with 1 ml of vaccine injected subcutaneously. Group 14 was injected subcutaneously with 1 ml of normal saline as a blank control. Blood was collected regularly after immunization to determine the titer of serum neutralizing antibodies. The specific results are shown in Table 5.

[0077] Table 5 Results of the immune duration test of the feline panleukopenia virus 708 strain vaccine composition

[0078] The results showed that after vaccination, the feline panleukopenia virus 708 strain vaccine composition can quickly induce the production of FPV neutralizing antibodies, and the level is still maintained at a high level 12 months after immunization.

[0079] This indicates that the feline panleukopenia virus 708 strain vaccine composition provided in the present application can enable the body to produce high titer specific antibodies in a short period of time after immunization, and can prevent feline panleukopenia for up to 12 months or even longer.

[0080] Example 7 Broad-spectrum test of feline panleukopenia virus 708 strain vaccine composition

[0081] 40 healthy susceptible antigen antibody negative cats aged 2 months were randomly divided into 8 groups, 5 in each group. Groups 15 to 18 were subcutaneously inoculated with 1 ml of inactivated vaccine 2, and groups 19 to 22 were subcutaneously injected with 1 ml of normal saline as blank controls. 21 days after immunization, the test cats were challenged with feline panleukopenia virus 020 strain, feline panleukopenia virus 021 strain, feline panleukopenia virus 707 strain, and feline panleukopenia virus 602 strain from Liaoning, Henan, Zhejiang, and Guangdong, respectively. Each cat was inoculated with 4 ml (10 5.5 FAID 50 / ml), and the body temperature, appetite, feces and other clinical manifestations of the cats were observed and recorded every day after the infection, and the peripheral blood leukocyte count was measured regularly. The specific results are shown in Table 6.

[0082] Table 6 Results of the broad-spectrum test of feline panleukopenia virus 708 strain vaccine composition

[0083] The results showed that all cats vaccinated with the feline panleukopenia virus 708 strain vaccine composition were protected, while all cats in the control group became ill.

[0084] The results show that the feline panleukopenia virus 708 strain vaccine composition provided by the present application can provide effective and complete immune protection against feline panleukopenia virus from different geographical sources. The vaccine composition of the present application has a broad spectrum of immunogenicity and can provide complete protection against feline panleukopenia virus from different geographical sources.

[0085] Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the technical concept of the present application, all of which belong to the protection scope of the present application.

Claims

1. Feline panleukopenia virus strain 708, accession number is CCTCC No.V202320.

2. Use of the feline panleukopenia virus 708 strain according to claim 1 in preparing a medicament for preventing diseases associated with feline panleukopenia virus infection.

3. The use according to claim 2, characterized in that: The drug is an inactivated feline panleukopenia virus vaccine.

4. A vaccine composition, characterized in that The vaccine composition comprises an immunizing amount of the antigen of the feline panleukopenia virus strain 708 according to claim 1 and a pharmaceutically acceptable carrier.

5. The vaccine composition according to claim 4, characterized in that The antigen is 1-15 generations of feline panleukopenia virus 708 strain or its culture.

6. The vaccine composition according to claim 5, characterized in that The antigen is the inactivated 1-15th generation feline panleukopenia virus 708 strain or its culture, preferably, the antigen content is 10 5.0 ~10 6.0 FAID 50 / ml, preferably 10 6.0 FAID 50 / ml.

7. The vaccine composition according to any one of claims 4 to 6, characterized in that The pharmaceutically acceptable carrier includes an adjuvant, which includes one or more of aluminum gel adjuvant, saponin, avridine, DDA, water-in-oil emulsion, oil-in-water emulsion, water-in-oil-in-water emulsion, polymer of acrylic acid or methacrylic acid, copolymer of maleic anhydride and alkenyl derivative, RIBI adjuvant system, Block co-polymer, SAF-M, monophosphoryl lipid A, Avridine lipid-amine adjuvant, Escherichia coli heat-labile enterotoxin, cholera toxin, IMS1314, muramyl dipeptide, and Gel adjuvant.

8. The vaccine composition according to claim 7, characterized in that The concentration of the adjuvant ranges from 5% V / V to 50% V / V, preferably 10% V / V.

9. A method for preparing the vaccine composition according to any one of claims 4 to 8, characterized in that: The feline panleukopenia virus 708 strain is cultured and proliferated, the proliferated feline panleukopenia virus 708 strain or its culture is inactivated, and a pharmaceutically acceptable carrier is added to the inactivated feline panleukopenia virus 708 strain or its culture.

10. The method according to claim 9, characterized in that The inactivation is inactivation with an inactivating agent.

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