WO2020215301A1 - 基因缺失的减毒非洲猪瘟病毒及其作为疫苗的应用 - Google Patents

基因缺失的减毒非洲猪瘟病毒及其作为疫苗的应用 Download PDF

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WO2020215301A1
WO2020215301A1 PCT/CN2019/084469 CN2019084469W WO2020215301A1 WO 2020215301 A1 WO2020215301 A1 WO 2020215301A1 CN 2019084469 W CN2019084469 W CN 2019084469W WO 2020215301 A1 WO2020215301 A1 WO 2020215301A1
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swine fever
african swine
virus
gene
mgf360
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PCT/CN2019/084469
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French (fr)
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步志高
陈伟业
赵东明
何希君
刘任强
柳金雄
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中国农业科学院哈尔滨兽医研究所（中国动物卫生与流行病学中心哈尔滨分中心）
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Priority to PCT/CN2019/084469 priority Critical patent/WO2020215301A1/zh
Priority to EP19925757.7A priority patent/EP3960850A4/en
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
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    • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
    • A61P31/12—Antivirals
    • A61P31/20—Antivirals for DNA viruses
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies
    • A61K39/12—Viral antigens
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies
    • A61K2039/51—Medicinal preparations containing antigens or antibodies comprising whole cells, viruses or DNA/RNA
    • A61K2039/525—Virus
    • A61K2039/5254—Virus avirulent or attenuated
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K39/00—Medicinal preparations containing antigens or antibodies
    • A61K2039/55—Medicinal preparations containing antigens or antibodies characterised by the host/recipient, e.g. newborn with maternal antibodies
    • A61K2039/552—Veterinary vaccine
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    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
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    • C12N2710/00—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA dsDNA viruses
    • C12N2710/00011—Details
    • C12N2710/12011—Asfarviridae
    • C12N2710/12034—Use of virus or viral component as vaccine, e.g. live-attenuated or inactivated virus, VLP, viral protein
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N2710/00—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA dsDNA viruses
    • C12N2710/00011—Details
    • C12N2710/12011—Asfarviridae
    • C12N2710/12071—Demonstrated in vivo effect

Definitions

  • the invention relates to the field of veterinary medicine, specifically to the prevention and treatment of animal diseases, and more specifically to attenuated African swine fever virus and vaccines.
  • African swine fever virus is the only member of the Asfarviridae family and mainly replicates in the cytoplasm of cells. African swine fever is an acute, violent and highly contagious infectious disease of domestic pigs and wild boars. The virulent strain can kill domestic pigs within 5-14 days of infection. The mortality rate is close to 100%. There is no effective preventive vaccine. No specific treatment drugs. Domestic pigs, wild boars and soft ticks at all stages are the natural hosts of African swine fever, which can be transmitted directly between domestic pigs and wild boars, through tick bites, and through virus-contaminated swill, feed, and cured dry ham And other pork products spread across countries and regions. When an epidemic is discovered, it must be culled. It is one of the most serious infectious diseases that harm pigs in the world and is the number one foreign animal disease that my country focuses on preventing.
  • African swine fever is a double-stranded DNA virus with a large genome and numerous genotypes (24 genotypes) [Quembo,CJ,et al.,Genetic characterization of African virus isolates from soft ticks at the wildlife/domestic interface in Mozambique and identification of a novel geneotype. Transbound Emerge Dis, 2018.65(2): p.420-431.], which encodes 150-167 kinds of proteins.
  • the immune escape mechanism is complex. Generally, multiple virulence genes work together.
  • CN 106459931 A discloses a functional form of attenuated African swine fever virus lacking the following genes: multigene family 360 genes 9L, 10L, 11L, 12L, 13L and 14L; and multigene family 505 genes 1R, 2R, 3R and 4R also provide functional forms of attenuated African swine fever virus lacking the D P148R gene. And discussed the different ways of administration, such as intramuscular injection, intranasal and oral administration.
  • WO 2012/107614 A1 mainly involves inhibiting the expression of pp220, pp62 or pB438L, and possibly deleting the CD2 gene and pol X gene.
  • WO2016049101A the African swine fever virus ASF-Georgia2007 mutant virus ASFV-G ⁇ 9GL (that is, the 172 nucleotide sequence of the 9GL gene deleted) is disclosed.
  • the preliminary study of the present invention also found that even if the same virulence gene deletion strategy is adopted, the attenuation effects of different genotypes are very different: for example, the BA71 strain (genotype I) lacking CD2V has been sufficiently attenuated, and pigs survived immunization The rate is 100% [Monteagudo, PL, et al., BA71DeltaCD2: a New Recombinant Live Attenuated African Swine Fever Virus with Cross-Protective Capabilities. J Virol, 2017.91(21).].
  • the survival rate of immunized pigs is about 50% (data not shown) and 0%; Benin 97/1 strain with DP148R missing (Gene Type I)[Reis,AL,et al.,Deletion of the African Swine Fever Virus Gene DP148R Does Not Reduce Virus Replication in Culture but Reduces Virus Virulence in Pigs and Induces High Levels of Virol Protection, 2017. 24).] It can also fully attenuate the virus, and the survival rate after immunization of pigs is also 100%, but the survival rate of the princes immunized with DP148R lacking the Chinese epidemic strain is only 0%, and the attenuation effect is extremely limited.
  • the inventors isolated the Chinese epidemic strain Pig/CN/HLJ/2018 in the early stage. After sequencing and sequence analysis, its full-length genome sequence (GenBank: MK333180.1) and DB/LN/2018 are both 189,404bp, while the PoL/2017 strain The total length is 189,401bp, and the insertion, deletion and mutation of the sequence are analyzed [Xuexia Wen et al. Genome sequences derived from pig and dried blood pig feed samples provide important insights into the transmission of China virus in swine. Emerging Microbes&Infections.2019,VOL.8]. Studies have shown that it is highly virulent and infectious [Dongming Zhao et al. Replication and virus in pigs of the first African swine fever virus isolated in China. Emerging Microbes&Infections. 2019, VOL. 8], so the development of related vaccines is very urgent, especially Pay attention to safety and effectiveness indicators.
  • the present invention uses genetic engineering methods to delete the virulence genes (CD2V and MGF360-505R) of the African swine fever isolates circulating in China, and obtain two deleted virus strains (rASFV ⁇ 360-eGFP and rASFV ⁇ CD2V/360- eGFP-mCherry), after systematic evaluation of immune and challenge protection efficacy, the potency and safety are excellent.
  • the present invention provides a gene deletion attenuated African swine fever virus, which is characterized in that the African swine fever virus of genotype II is obtained by deleting the MGF360-505R gene, or by deleting the CD2V and MGF360-505R genes. More preferably, the combined deletion of MGF360-505R refers to the deletion of all the two gene sequences of MGF360 and 505R, or the combined deletion of CD2V and MGF360-505R refers to the deletion of all the three gene sequences of CD2V, MGF360, and 505R.
  • the genotype II African swine fever virus is a Chinese epidemic strain Pig/CN/HLJ/2018, and its full-length sequence has been published in GenBank (GenBank: MK333180.1).
  • the preferred MGF360-505R gene deletion virus of the present invention has deleted the 27942-35500th nucleotide relative to the original strain's full-length sequence; the CD2V and MGF360-505R gene deletion virus has deleted the original strain's full-length sequence Nucleotides 27942-35500 and 73394-74476. More specifically constructed MGF360-505R gene deletion virus, and CD2V and MGF360-505R combined deletion gene deletion virus, have been patented and deposited in the China Type Culture Collection on April 11, 2019. The deposit numbers are CCTCC NO. :V201925 and CCTCC NO:V201924.
  • the present invention also provides a vaccine comprising the attenuated African swine fever virus of the present invention, which induces a protective immune response in a subject against subsequent African swine fever virus challenge.
  • the vaccine can contain multiple attenuated African swine fever viruses of different genotypes. Such vaccines may be able to induce cross-protective immune responses against multiple ASF virus genotypes.
  • the invention also provides a pharmaceutical composition containing one or more of the African swine fever virus reduced of the invention.
  • the pharmaceutical composition can be used to prevent or treat African swine fever.
  • the vaccine or pharmaceutical composition may comprise one or more of the attenuated African swine fever virus of the present invention, and further optionally comprise one or more adjuvants, excipients, carriers and diluents.
  • the adjuvant can be any suitable adjuvant, chemical immune adjuvants such as aluminum hydroxide, Freund’s adjuvant, mineral oil, Span, etc.; microbial immune adjuvants such as mycobacteria, BCC, lipopolysaccharide, muramyl Peptides, cytosines, fat-soluble wax D, Corynebacterium parvum; plant immune adjuvants are mostly polysaccharides extracted from plants or large fungi, such as tuckahoe polysaccharides, safflower polysaccharides, and Chinese herbal medicines. And biochemical immune adjuvants such as thymosin, transfer factor, interleukin and so on. Preferred adjuvants can be nano adjuvant biological adjuvants, interleukins, interferons and the like.
  • chemical immune adjuvants such as aluminum hydroxide, Freund’s adjuvant, mineral oil, Span, etc.
  • microbial immune adjuvants such as mycobacter
  • the vaccine of the present invention can also be used in combination vaccines, such as combination with other vaccines for pigs, but the focus is on live attenuated vaccines, especially the integration of virus genes, such as bivalent vaccines, trivalent vaccines, etc.
  • the combination vaccine can contain multiple attenuated non-swine fever viruses of different genotypes, so that a cross-protective immune response against multiple non-swine fever virus genotypes can be induced.
  • the vaccine of the present invention can be administered in convenient ways, such as intramuscular injection, intranasal, oral, subcutaneous, transdermal and vaginal routes.
  • the attenuated vaccine of the present invention is preferably injected intramuscularly, and the appropriate dose is 10 2.5 -10 2.5 TCID 50 , and the preferred dose is 10 3 -10 3 TCID 50 .
  • the vaccine can be administered after the prime-boost regimen.
  • the subject may receive a second booster administration after a period of time (e.g., about 7, 14, 21, or 28 days).
  • the dose for booster administration is the same or lower than the dose for priming administration.
  • a third booster immunization can also be performed, for example, 2-3 months, 6 months or one year after immunization.
  • the gene-deficient attenuated African swine fever virus obtained in the present invention has the following advantages. After immunizing pigs with two gene-deficient African swine fever viruses (rASFV ⁇ 360-eGFP and rASFV ⁇ CD2V/360-eGFP-mCherry) constructed in the present invention, animals in the immunized group with a dose of 10 5 TCID 50 had no clinical symptoms such as elevated body temperature , The isolation of blood and organ viruses was negative, and the survival rate was 100%, indicating that it was sufficiently weakened, it is very safe as a vaccine, and both are superior to similar foreign studies on genotype II ASFV [Borca, MV, et al .,Deletion of a CD2-like gene,8-DR,from African swine fever virus affects viral infection in domestic swine.J Virol,1998.72(4):p.2881-9; O'Donnell,V.,et al.
  • the rASFV ⁇ 360-eGFP and rASFV ⁇ CD2V/360-eGFP-mCherry constructed by the present invention have an immune protection rate of 100%, and the positive rate of blood virus isolation is less than 35% and 100% respectively.
  • the two strains of gene-deleted viruses constructed in the present invention can provide sufficient protection against virulent attacks 21 days after immunization, which is better than 28 days abroad [O'Donnell, V., et al., African Swine Fever Virus Georgia Isolate Harboring Deletions of MGF360 and MGF505 Genes Is Attenuated in Swine and Confers Protection against Challenge with Virulent Parental Virus.J Virol,2015.89(11):p.6048-56].
  • the gene-deficient African swine fever virus (rASFV ⁇ 360-eGFP and rASFV ⁇ CD2V/360-eGFP-mCherry) constructed by the present invention has great application value.
  • the preservation information The specific virus based on the CN/HLJ/18 strain of the MGF360-505R gene deletion and the specific virus with the combined deletion of CD2V and MGF360-505R have been deposited under the patent procedure on April 11, 2019. At the China Center for Type Culture Collection, the deposit numbers are CCTCC NO:V201925 and CCTCC NO:V201924.
  • FIG. 1 Schematic diagram of vector construction for CD2V gene deletion.
  • Figure 2 Schematic diagram of the construction of a vector (expressing green fluorescence) for MGF360-505R gene deletion.
  • Figure 3 Schematic diagram of the construction of a vector (expressing red fluorescence) for MGF360-505R gene deletion.
  • Figure 4 African swine fever gene deletion virus expresses green or red and green double-color fluorescent protein.
  • Figure 5 Purification and identification of African swine fever gene deletion virus.
  • ⁇ CD2V is rASFV ⁇ CD2V-eGFP
  • ⁇ 360 is rASFV ⁇ 360-eGFP
  • CD2V/360 is rASFV ⁇ CD2V/360-eGFP-mCherry.
  • Figure 7 The body temperature changes of rASFV ⁇ 360-eGFP and rASFV ⁇ CD2V/360-eGFP-mCherry immunized pigs and cohabiting pigs after challenge.
  • Figure 8 Survival rate of test pigs after immunization or challenge.
  • ⁇ CD2V is rASFV ⁇ CD2V-eGFP
  • ⁇ 360 is rASFV ⁇ 360-eGFP
  • CD2V/360 is rASFV ⁇ CD2V/360-eGFP-mCherry.
  • the Chinese epidemic strain of African swine fever virus (African swine fever virus, ASFV/CN/HLJ/18 strain, also known as the Chinese epidemic strain of African swine fever virus Pig/CN/HLJ/2018) was isolated and combined by the Harbin Institute of Veterinary Medicine, Chinese Academy of Agricultural Sciences Save (see GenBank: MK333180.1 for its full-length sequence).
  • Porcine alveolar macrophages (Primary porcine alveolar macrophages, PAM) were derived from SPF pigs aged 30-50 days in 1640 medium containing 10% FBS (purchased from Thermo Scientific, USA).
  • Peripheral blood mononuclear cells Peripheral Blood Mononuclear Cell, PBMC were isolated from SPF pig EDTA anticoagulant blood using a PBMC isolation kit (purchased from China TBD company).
  • Example 1 Homologous recombination vector construction
  • the left and right homology arms of MGF360-505R (about 1000 bp on the left side of the 5'-aagccctgagaacagcagca-3' sequence of the ASF genome and about 1000 bp on the right side of the 5'-gcgagacgtttcaataaaag-3' sequence) (relative to the full-length sequence position at the 27942-35500) Position), p72 promoter[Reis,AL,et al.,Deletion of the African Swine Fever Virus Gene DP148R Does Not Reduce Virus Replication in Culture but Reduces Virus Virus in Pigs and Inducin Highction Promote, 2017.
  • PCR fragments of 4 genes including eGFP were cloned into the pBluescript II KS(+) vector with a one-step cloning kit.
  • the eGFP gene was expressed under the control of the p72 promoter to obtain the plasmid pB-LR ⁇ 360-eGFP (figure 2).
  • Example 2 Construction, purification and identification of gene deletion African swine fever virus
  • the plasmids pB-LR ⁇ 360-eGFP and pB-LR ⁇ 360-mCherry were respectively transfected with TransIT-LT1 transfection reagent (purchased from Mirus Bio, USA) into PAM cells infected with ASFV, and CD2V and MGF360 were purified by plaque cloning method -African swine fever gene deletion virus with 505R gene deletion and green fluorescent protein expression simultaneously [Reis, AL, et al.,Deletion of the African Swine Fever Virus Gene DP148R Does Not Reduce Virus Replication in Culture but Reduces Virus Virus and in Induces High Levels of Protection against Challenge.J Virol,2017.91(24).;Chen,W.,etal.,A goal poxvirus-vectored peste-des-petits-ruminants vaccine induces long-lasting neutralization antibody to high level andsheep.Vaccine,2010.28(30):p.4742-50.;Chen Weiye,et
  • the homologous recombination plasmid pB-LR ⁇ 360-mCherry was transfected into rASFV ⁇ CD2V-eGFP-infected PAM cells according to the above method, and the virus with double deletion of CD2V and MGF360-505R genes was obtained through multiple rounds of plaque purification, and named It is rASFV ⁇ CD2V/360-eGFP-mCherry (the deposit number is CCTCC NO:V201924). Relative to the full-length sequence of the Chinese epidemic strain of African swine fever Pig/CN/HLJ/2018, nucleotides 73394-74476 and nucleotides 27942-35500 are deleted at the same time.
  • the virus genome extraction kit (purchased from Beijing Tiangen Biotechnology Co., Ltd.) was used to extract the genomes of ASFV and the three gene-deleted ASFV, respectively for CD2V (5'-CACCACCTGAATCTAATGAAG-3' and 5'-GCGGGATATTGGGTAGTAG-3') and MGF360 -505R (5'-CGTCTATTTGGATGTTTT-3' and 5'-CGGCAGTATTATTTTGTG-3') primers are identified by PCR to confirm whether the deletion is successful.
  • the transfected and purified gene deletion viruses rASFV ⁇ CD2V-eGFP, rASFV ⁇ 360-eGFP and rASFV ⁇ CD2V/360-eGFP-mCherry respectively express green, green, red and green double-color fluorescence when infecting PAM cells (Figure 4).
  • the deletion genes of the three viruses were identified by PCR.
  • the results ( Figure 5) showed that the ASFV control all amplified CD2V and MGF360 gene fragments, while the gene deletion viruses did not amplify the corresponding deleted genes.
  • the titration of African swine fever virus was performed using two methods: half cell infection dose (50% Tissue Culture Infectious Dose, TCID 50 ) and half blood cell adsorption (50% haemadsorption, HAD 50 ).
  • the TCID 50 titration is carried out according to the following steps: Dilute ASFV with serum-free 1640 medium and then make 10-fold serial dilutions, inoculate PAM cells cultured in 96-well culture plates with a density of about 90-100%, and inoculate 8 wells for each dilution. 0.02mL per well, after 1 hour incubation at 37°C and 5% CO2, add 0.1mL 1640 complete culture medium containing 10% fetal bovine serum to each well, and incubate at 37°C and 5% CO2 , Observe for 3-7 days, calculate the half-cell infection (TCID 50 ) according to cytopathic or green fluorescence and Reed and Muench method [4].
  • the HAD 50 test is operated according to the literature [5] and adjusted appropriately: inoculate primary PBMC in a 96-well cell culture plate, and perform a 10-fold gradient dilution of the sample to be tested, inoculate 0.02ml per well, the virus infection can be based on the red blood cell
  • the rosettes formed around the infected cells were judged and observed for 7 days according to the Reed and Muench method [Reed, L. and H. Muench, A simple method of estimaing fifty percent endpoints. American Journal of Epidemiology 1938.27: p.493-497 ]Calculate half of the absorbed dose of blood cells (HAD 50 )
  • the body temperature test after immunization showed that after rASFV ⁇ 360-eGFP immunized pigs, whether it was the high-dose (10 5 TCID 50 , No. 90-93) immunization group or the low-dose immunization group (10 3 TCID 50 , 95- No. 98) had no significant increase in body temperature, and the survival rate was 100% (Figure 8); among them, the No. 90 pig died accidentally on the 16th day. There was no obvious disease in the autopsy organ, and the blood poison result was negative. After rASFV ⁇ CD2V/360-eGFP-mCherry immunized pigs, there was no temperature rise in either the high-dose (10 5 TCID 50 , No.
  • immunization group or the low-dose immunization group (10 3 TCID 50 , No. 85-88) High phenomenon.
  • cohabiting pigs (No. 101 and No. 102) also showed no increase in body temperature.
  • the immunized pigs and cohabiting pigs have no abnormal mental status and feeding status after immunization, and no obvious clinical symptoms
  • Table 3-1 The blood virus isolation and detection of pigs immunized with rASFV ⁇ 360-eGFP and rASFV ⁇ CD2V/360-eGFP-mCherry
  • Coju pigs No. 101 and No. 102 showed clinical symptoms such as elevated body temperature (40.5-42°C) ( Figure 7), depression, and decreased feeding intake on day 5-7 after challenge.

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Abstract

可作为疫苗的基因缺失减毒非洲猪瘟病毒，疫苗以及构建方法。该构建方法包括采用非洲猪瘟中国流行株Pig/CN/HLJ/2018，经基因工程技术，将非洲猪瘟病毒的毒力基因缺失，获得MGF360-505R缺失和CD2V与MGF360-505R联合缺失的基因缺失病毒。

Description

基因缺失的减毒非洲猪瘟病毒及其作为疫苗的应用 技术领域
本发明涉及兽医领域,具体为动物疾病预防和治疗,更具体涉及减毒的非洲猪瘟病毒和疫苗。
背景技术
非洲猪瘟病毒是非洲猪瘟病毒科(Asfarviridae)家族的唯一成员，并且主要在细胞的细胞质中复制。非洲猪瘟是家猪和野猪的一种急性、烈性、高度接触性传染病，强毒株可在感染的约5‐14天内杀死家猪，其中死亡率接近100％，无有效预防疫苗，无特效治疗药物。各阶段家猪、野猪和软蜱是非洲猪瘟自然宿主，可在家猪和野猪之间直接传播，也可通过蜱虫叮咬传播，还可以通过污染了病毒的泔水、饲料以及腌制的干火腿等猪肉产品跨国家和地区传播。发现疫情，必须进行扑杀，是全球防范内危害猪群最严重的传染病之一，是我国重点防范的头号外来动物疫病。
我国生猪养殖占世界50％以上。根据非洲猪瘟在全球范围内流行发展特点及我国生猪养殖业现状，非洲猪瘟疫情将在我国进一步扩大并长期存在。一是由于我国生猪养殖量巨大，整体养殖水平低，生物安全防范条件差，生猪跨区域调运频繁，且存在野生宿主，为非洲猪瘟疫情的传播提供了便利条件。二是周边国家疫情国家逐年增多，存在自然疫病病源地。三是根据国外非洲猪瘟疫净化根除历史看，一旦发生非洲猪瘟疫情，要彻底根除，均需要花费漫长的时间，并付出重大的代价。因此，必须加快开展非洲猪瘟流行病学、相关致病机制、快速诊断检测技术产品和防治疫苗的研究，并做好长期应对复杂的非洲猪瘟疫情防控的技术和政策部署。根据我国国情和已有病毒病防控经验，疫苗是防控非洲猪瘟疫情最为有效和经济的方法，研制有效、安全的疫苗十分迫切！尤其是2018年8月初我国爆发非洲猪瘟疫情，截至2019年1月14日，已有24个省份发生过疫情，扑杀生猪超过91.6万头，造成直接经济损失数十亿元，间接损失无法计量，给 我国生猪养殖业和国民经济带来巨大损失。由于在我国首次发生，缺乏对非洲猪瘟的系统科学认知和有效防控技术体系，仅能依靠扑杀、消毒等措施进行防控，给疫情防控带来了极大困难。
非洲猪瘟病毒自从发现100多年来，采用传统疫苗研制策略[Forman,A.J.,R.C.Wardley,and P.J.Wilkinson,The immunological response of pigs and guinea pigs to antigens of African swine fever virus.Arch Virol,1982.74(2‐3):p.91‐100；Mebus,C.A.,African swine fever.Adv Virus Res,1988.35:p.251‐69；Stone,S.S.and W.R.Hess,Antibody response to inactivated preparations of African swine fever virus in pigs.Am J Vet Res,1967.28(123):p.475‐81.](包括灭活疫苗、自然弱毒或传代致弱疫苗等)、新型佐剂[Blome,S.,C.Gabriel,and M.Beer,Modern adjuvants do not enhance the efficacy of an inactivated African swine fever virus vaccine preparation.Vaccine,2014.32(31):p.3879‐82.]和亚单位疫苗等新型疫苗[Jancovich,J.K.,et al.,Immunization of Pigs by DNA Prime and Recombinant Vaccinia Virus Boost To Identify and Rank African Swine Fever Virus Immunogenic and Protective Proteins.J Virol,2018.92(8)；Gomez‐Puertas,P.,et al.,The African swine fever virus proteins p54and p30are involved in two distinct steps of virus attachment and both contribute to the antibody‐mediated protective immune response.Virology,1998.243(2):p.461‐71；Neilan,J.G.,et al.,Neutralizing antibodies to African swine fever virus proteins p30,p54,and p72 are not sufficient for antibody‐mediated protection.Virology,2004.319(2):p.337‐42；Ruiz‐Gonzalvo,F.,F.Rodriguez,and J.M.Escribano,Functional and immunological properties of the baculovirus‐expressed hemagglutinin of African swine fever virus.Virology,1996.218(1):p.285‐9；Lacasta,A.,et al.,Expression library immunization can confer protection against lethal challenge with African swine fever virus.J Virol,2014.88(22):p.13322‐32.]等研制策略，均未成功，使得该疫病多年来到处肆掠，从非洲向全世界范围蔓延。紧靠扑杀策略，仅仅有西班牙、巴西等屈指可数的国家成功控制住非洲猪瘟。但由于我国猪饲养量巨大，仅仅靠扑杀手段，成本太高，安全、有效的疫苗是控制我国非洲猪瘟疫情的迫切需求！目前，通过基因缺失致弱成为非洲猪瘟疫苗研究重要的方向。
非洲猪瘟是由双链DNA病毒，基因组较大，基因型众多(24个基因型)[Quembo,C.J.,et al.,Genetic characterization of African swine fever virus isolates  from soft ticks at the wildlife/domestic interface in Mozambique and identification of a novel genotype.Transbound Emerg Dis,2018.65(2):p.420‐431.]，编码150‐167种蛋白，免疫逃逸机制复杂，一般是由多个毒力基因共同发挥作用，这就导致不同基因型之间的生物学特性差异较大，不同基因型之间交叉免疫保护能力较差[Souto,R.,et al.,Vaccine Potential of Two Previously Uncharacterized African Swine Fever Virus Isolates from Southern Africa and Heterologous Cross Protection of an Avirulent European Isolate.Transbound Emerg Dis,2016.63(2):p.224‐31；King,K.,et al.,Protection of European domestic pigs from virulent African isolates of African swine fever virus by experimental immunisation.Vaccine,2011.29(28):p.4593‐600.]。
在CN 106459931 A中公开了缺失以下基因的功能性形式的减毒的非洲猪瘟病毒：多基因家族360基因9L，10L，11L，12L，13L和14L；和多基因家族505基因1R，2R，3R和4R，还提供了缺乏D P148R基因的功能性形式的减毒非洲猪瘟病毒。并探讨了不同施药方式如如通过肌内注射肌肉注射、鼻内和口服等。
在US9474797B1中，给出非洲猪瘟病毒ASF‐GVAV的全长DNA序列，其中对位置为178643至182578的片段缺失导致MGF505‐11L，MGF100‐1L，17L18L ASFV G ACD 01870，I9R，I10L I11L阅读框的缺失，还结合有其他多种突变而获得的减毒的非洲猪瘟病毒；在US9528094B2中公开一种非洲猪瘟病毒ASF‐Georgia2007的突变病毒，其在10 2‐10 4HAD 50剂量下可产生有效保护，突变主要是造成MGF5001R和3R基因的部分缺失以及MGF360基因12L，13L和14L以及MGF5002R的全部缺失。而WO 2012/107614 A1主要涉及抑制pp220,pp62或pB438L的表达，以及可能缺失CD2基因和pol X基因。在WO2016049101A中公开了非洲猪瘟病毒ASF‐Georgia2007突变病毒ASFV‐G△9GL(即缺失9GL基因的172个核苷酸序列)。
本发明前期研究也发现，即使是采用相同的毒力基因缺失策略，不同基因型的致弱效果却差别很大：例如CD2V缺失的BA71株(基因I型)已经充分致弱，免疫猪后存活率均100％[Monteagudo,P.L.,et al.,BA71DeltaCD2:a New Recombinant Live Attenuated African Swine Fever Virus with Cross‐Protective Capabilities.J Virol,2017.91(21).]。但相同基因缺失的中国流行株(基因II型)和 Malawi Lil‐20/1株(基因II型)[Borca,M.V.,et al.,Deletion of a CD2‐like gene,8‐DR,from African swine fever virus affects viral infection in domestic swine.J Virol,1998.72(4):p.2881‐9]免疫猪后的存活率分别约50％(数据未显示)和0％；DP148R缺失的Benin 97/1株(基因I型)[Reis,A.L.,et al.,Deletion of the African Swine Fever Virus Gene DP148R Does Not Reduce Virus Replication in Culture but Reduces Virus Virulence in Pigs and Induces High Levels of Protection against Challenge.J Virol,2017.91(24).]也能够使得病毒充分致弱，免疫猪后存活率也是100％，但DP148R缺失中国流行株免疫诸侯的存活率仅仅为0％，减毒效果极其有限。
发明人前期分离得到中国流行株Pig/CN/HLJ/2018，经测序和序列分析，其全长基因组序列(GenBank:MK333180.1)与DB/LN/2018均为189,404bp，而PoL/2017株的全长为189,401bp，并分析序列的插入，缺失和突变情况[Xuexia Wen et al.Genome sequences derived from pig and dried blood pig feed samples provide important insights into the transmission of African swine fever virus in China in 2018.Emerging Microbes&Infections.2019,VOL.8]。研究表明其具有高毒力和传染性[Dongming Zhao et al.Replication and virulence in pigs of the first African swine fever virus isolated in China.Emerging Microbes&Infections.2019,VOL.8]，因此研制相关疫苗十分迫切，尤其要注意安全性和有效性指标。
发明内容
针对非洲猪瘟疫苗缺乏和已知疫苗的有效性不够理想，尤其国内疫苗的空白，研发非洲猪瘟基因缺失减毒疫苗的制备方法，并成功获得了两株安全、有效的疫苗株。
本发明是采用基因工程手段，对中国流行的非洲猪瘟分离株进行毒力基因(CD2V和MGF360‐505R)缺失，获得了两株缺失毒株(rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry)，经过免疫和攻毒保护效力等系统评价，将效价和安全性均表现优异。
[根据细则91更正 19.08.2019]　
因此，本发明提供一种基因缺失减毒非洲猪瘟病毒，其特征在于，将基因II型的非洲猪瘟病毒进行MGF360-505R基因缺失，或进行CD2V与MGF360-505R基因联合缺失而得到的。更优选的是MGF360‐505R联合缺失是指MGF360和505R 两种基因全部序列缺失，或者CD2V与MGF360‐505R联合基因缺失是指CD2V、MGF360、505R三种基因序列全部缺失。
[根据细则91更正 19.08.2019]　
优选地，所述基因II型的非洲猪瘟病毒是中国流行株Pig/CN/HLJ/2018，其全长序列已于GenBank公开(GenBank:MK333180.1)。
本发明优选的MGF360-505R基因缺失病毒相对于原始毒株全长序列缺失了第27942-35500位核苷酸；所述CD2V与MGF360-505R基因联合缺失病毒相对于原始毒株全长序列缺失了第27942-35500位和第73394-74476位核苷酸。更具体构建的MGF360‐505R基因缺失病毒，和CD2V与MGF360‐505R联合缺失的基因缺失病毒，已于2019年4月11日进行专利程序保藏于中国典型培养物保藏中心，保藏号分别是CCTCC NO:V201925和CCTCC NO:V201924。
进一步地，本发明还提供了包含本发明的减毒非洲猪瘟病毒的疫苗，本发明的疫苗在受试者中诱导针对随后的非洲猪瘟病毒攻击的保护性免疫应答。
疫苗可以包含不同基因型的多种减毒非洲猪瘟病毒。此类疫苗可以能够诱导针对多种ASF病毒基因型的交叉保护性免疫应答。
本发明还提供了包含一种或多种本发明的减非洲猪瘟病毒的药物组合物。该药物组合物可用于预防或治疗非洲猪瘟。疫苗或药物组合物可以包含一种或多种本发明的减毒非洲猪瘟病毒，进一步任选地包含一种或多种佐剂，赋形剂，载体和稀释剂。佐剂可以任何合适的佐剂，化学类免疫佐剂如氢氧化铝、弗氏佐剂、矿物油、司盘等；微生物类免疫佐剂如分枝杆菌、BCC、脂多糖、胞壁酰二肽、胞肽、脂溶性蜡质D、短小棒状杆菌；植物类免疫佐剂多为从植物或大真菌中提取的多糖类，如茯苓多糖、红花多糖、中草药类等。而生化类免疫佐剂如胸腺肽、转移因子、白细胞介素等。优选的佐剂可以是纳米佐剂生物佐剂，白介素、干扰素等。
本发明的疫苗也可用于联合疫苗，如与猪的其他疫苗联合，但重点在减毒活疫苗上，尤其是病毒基因的整合，如双价苗，三价苗等。联合疫苗可以包含不同基因型的多种减毒非猪瘟病毒，如此可以诱导针对多种非猪瘟病毒基因型的交叉保护性免疫应答。
本发明的疫苗的施用可以采用方便的途径，例如肌内注射，鼻内，口服，皮下，透皮和阴道等途径。本发明的减毒疫苗优选采用肌肉注射，合适的剂量为10 2.5‐10 2.5TCID 50，优选剂量为10 3‐10 3TCID 50。疫苗可以在初免-加强方案后施用。 例如，在第一次接种后，受试者可以在一段时间(例如约7，14，21或28天)之后接受第二次加强施用。通常，加强施用的剂量相同或低于初免施用的剂量。此外，也可以进行第三次加强免疫，例如免疫后2-3个月、6个月或一年。
本发明获得的基因缺失的减毒非洲猪瘟病毒具有下述优势。本发明构建的两株基因缺失非洲猪瘟病毒(rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry)在免疫猪后，即使10 5TCID 50剂量免疫组动物均无体温升高等临床症状，血液和脏器病毒分离均为阴性，存活率均为100％，表明其充分致弱，作为疫苗是非常安全的，且均优于国外基因II型ASFV的类似研究[Borca,M.V.,et al.,Deletion of a CD2‐like gene,8‐DR,from African swine fever virus affects viral infection in domestic swine.J Virol,1998.72(4):p.2881‐9；O'Donnell,V.,et al.,African Swine Fever Virus Georgia Isolate Harboring Deletions of MGF360 and MGF505 Genes Is Attenuated in Swine and Confers Protection against Challenge with Virulent Parental Virus.J Virol,2015.89(11):p.6048‐56.](表1)：国外采用我国流行株同源性极高的Georgia株构建了MGF360‐505R基因缺失病毒，在免疫猪后的血液病毒分离阳性率在60％以上；采用基因II型Malawi Lil‐20/1株构建的CD2V单基因缺失病毒，在免疫猪后血液病毒分离阳性率为100％、存活率仅为0％。其次，在有效性方面，强毒攻击后，本发明构建的rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry免疫保护率均为100％，血液病毒分离阳性率分别小于35％和100％，但在第21‐22天均转为阴性，表明两株病毒都具有极佳的免疫保护效力，也明显优于国外采用基因II型ASFV的类似研究[Borca,M.V.,et al.,Deletion of a CD2‐like gene,8‐DR,from African swine fever virus affects viral infection in domestic swine.J Virol,1998.72(4):p.2881‐9；O'Donnell,V.,et al.,African Swine Fever Virus Georgia Isolate Harboring Deletions of MGF360 and MGF505 Genes Is Attenuated in Swine and Confers Protection against Challenge with Virulent Parental Virus.J Virol,2015.89(11):p.6048‐56.](表1)：国外MGF360‐505R缺失Georgia株病毒免疫猪在攻毒后的血液病毒分离阳性率为70％[O'Donnell,V.,et al.,African Swine Fever Virus Georgia Isolate Harboring Deletions of MGF360 and MGF505 Genes Is Attenuated in Swine and Confers Protection against Challenge with Virulent Parental Virus.J Virol,2015.89(11):p.6048‐56](其中，本发明采用的10 3TCID 50免疫剂量小于国外的10 4 HAD 50，但攻毒后血液病毒分离阳性率仅为25％)；虽然本发明构建的MGF360‐505R和CD2V双基因缺失病毒免疫猪在攻毒后血液病毒分离阳性率为100％，略差于MGF360‐505R基因缺失的病毒，但显著优于CD2V单缺失的基因II型Malawi Lil‐20/1株病毒(免疫后死亡率100％)[Borca,M.V.,et al.,Deletion of a CD2‐like gene,8‐DR,from African swine fever virus affects viral infection in domestic swine.J Virol,1998.72(4):p.2881‐9]，且攻毒后21天血液病毒分离就转为阴性。最后，本发明构建的两株基因缺失病毒免疫后21天就能够提供充分的强毒攻击保护，优于国外的28天[O'Donnell,V.,et al.,African Swine Fever Virus Georgia Isolate Harboring Deletions of MGF360 and MGF505 Genes Is Attenuated in Swine and Confers Protection against Challenge with Virulent Parental Virus.J Virol,2015.89(11):p.6048‐56]。因此，采用流行地区的分离株来构建非洲猪瘟基因缺失减毒疫苗是最佳策略，也是中国研制非洲猪瘟疫苗的关键。因此，本发明构建的基因缺失非洲猪瘟病毒(rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry)具有巨大的应用价值。
表1国内外类似基因缺失减毒非洲猪瘟病毒(基因II型)的安全性比较
Figure PCTCN2019084469-appb-000001
注：“—”表示未攻毒(由于该毒株免疫就已经导致猪全部死亡)。
其中的保藏信息：本发明基于CN/HLJ/18株的MGF360‐505R基因缺失的具体病毒，和CD2V与MGF360‐505R联合缺失的基因缺失的具体病毒已于2019年4月11日进行专利程序保藏于中国典型培养物保藏中心，保藏号分别是CCTCC NO:V201925和CCTCC NO:V201924。
附图说明
图1用于CD2V基因缺失的载体构建示意图。
图2用于MGF360-505R基因缺失的载体(表达绿色荧光)构建示意图。
图3用于MGF360-505R基因缺失的载体(表达红色荧光)构建示意图。
图4非洲猪瘟基因缺失病毒表达绿色或红绿双色荧光蛋白。
图5非洲猪瘟基因缺失病毒纯化鉴定。
其中，△CD2V为rASFV△CD2V-eGFP，△360为rASFV△360-eGFP，CD2V/360为rASFV△CD2V/360-eGFP-mCherry。
[根据细则26改正22.05.2019]　
图6rASFV△360-eGFP和rASFV△CD2V/360-eGFP-mCherry免疫猪和同居猪的体温变化。
图7rASFV△360-eGFP和rASFV△CD2V/360-eGFP-mCherry免疫猪及同居猪攻毒后的体温变化。
图8免疫后或攻毒后试验猪的存活率。
其中，△CD2V为rASFV△CD2V-eGFP，△360为rASFV△360-eGFP，CD2V/360为rASFV△CD2V/360-eGFP-mCherry。
具体实施方式
下面通过具体实施方式对本发明作进一步的说明，以列好的理解本发明，但其不构成对本发明的限制。
实施例中所用材料与方法
非洲猪瘟病毒中国流行株(African swine fever virus，ASFV/CN/HLJ/18株，也称为非洲猪瘟病毒中国流行株Pig/CN/HLJ/2018)由中国农业科学院哈尔滨兽医研究所分离并保存(其全长序列参见GenBank:MK333180.1)。猪肺泡巨噬细胞(Primary porcine alveolar macrophages，PAM)来自于30‐50日龄的SPF猪，于含有10％FBS(购自美国Thermo Scientific公司)的1640培养基。外周血单核 细胞(Peripheral Blood Mononuclear Cell，PBMC)用PBMC分离试剂盒(购自中国TBD公司)从SPF猪EDTA抗凝血中分离获得。
实验中的操作如果没有特别说明均是本领域知晓的操作方法。
实施例一、同源重组载体构建
将CD2V基因ORF左右约1000bp的基因组(作为左右同源臂，序列位置相对于全长序列在第73394-74476位)和eGFP的PCR片段用一步克隆试剂盒(购自中国诺唯赞生物科技有限公司)克隆至pBluescript II KS(+)载体，其中eGFP基因使用CD2V基因自身的启动子进行表达，获得质粒pB‐LR△CD2V‐eGFP(图1)。
将MGF360‐505R(ASF基因组的5’‐aagccctgagaacagcagca‐3’序列左侧约1000bp和5’‐gcgagacgtttcaataaaag‐3’序列右侧约1000bp)左右同源臂(相对于全长序列位置在第27942-35500位)、p72启动子[Reis,A.L.,et al.,Deletion of the African Swine Fever Virus Gene DP148R Does Not Reduce Virus Replication in Culture but Reduces Virus Virulence in Pigs and Induces High Levels of Protection against Challenge.J Virol,2017.91(24)]和eGFP等4个基因的PCR片段用一步克隆试剂盒克隆至pBluescript II KS(+)载体，其中eGFP基因在p72启动子的控制下进行表达，获得质粒pB‐LR△360‐eGFP(图2)。将pB‐LR△360‐eGFP中的eGFP基因替换为mCherry基因，获得质粒pB‐LR△360‐mCherry(图3)。
实施例二、基因缺失非洲猪瘟病毒的构建、纯化和鉴定
将质粒pB‐LR△360‐eGFP和pB‐LR△360‐mCherry用TransIT‐LT1transfection reagent(购自美国Mirus Bio公司)分别转染至感染了ASFV的PAM细胞，采用噬斑克隆方法纯化CD2V和MGF360‐505R基因分别缺失、同时表达绿色荧光蛋白的非洲猪瘟基因缺失病毒[Reis,A.L.,et al.,Deletion of the African Swine Fever Virus Gene DP148R Does Not Reduce Virus Replication in Culture but Reduces Virus Virulence in Pigs and Induces High Levels of Protection against Challenge.J Virol,2017.91(24).；Chen,W.,et al.,A goat poxvirus‐vectored peste‐des‐petits‐ruminants vaccine induces long‐lasting neutralization antibody to high levels in goats and sheep.Vaccine,2010.28(30):p.4742‐50.；陈伟业,et al.,表达小反刍兽疫H蛋白的重组山羊痘病毒疫苗的研究.生物工程学报,2009.25(4):p.496‐502.]，分别命名为rASFV △CD2V‐eGFP和rASFV△360‐eGFP(保藏号是CCTCC NO:V201925)。其中相对于非洲猪瘟中国流行株Pig/CN/HLJ/2018的全长序列而言，前者缺失了第73394-74476位核苷酸，后者缺失了第27942-35500位核苷酸。
同理，将同源重组质粒pB‐LR△360‐mCherry按照上述方法转染至rASFV△CD2V‐eGFP感染的PAM细胞，通过多轮噬斑纯化获得CD2V和MGF360‐505R基因双缺失的病毒，命名为rASFV△CD2V/360‐eGFP‐mCherry(保藏号是CCTCC NO:V201924)。其中相对于非洲猪瘟中国流行株Pig/CN/HLJ/2018的全长序列而言，同时缺失了第73394-74476位核苷酸，和第27942-35500位核苷酸。
用病毒基因组提取试剂盒(购自北京天根生物科技公司)提取ASFV和三种基因缺失ASFV的基因组，分别用针对CD2V(5’‐CACCACCTGAATCTAATGAAG‐3’和5’‐GCGGGATATTGGGTAGTAG‐3’)和MGF360‐505R(5’‐CGTCTATTTGGATGTTTT‐3’和5’‐CGGCAGTATTATTTTGTG‐3’)的引物进行PCR鉴定，确认是否缺失成功。
经过转染和纯化的基因缺失病毒rASFV△CD2V‐eGFP、rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry在感染PAM细胞是分别表达绿色、绿色、红绿双色荧光(图4)。对三种病毒的缺失基因进行PCR鉴定，结果(图5)表明，ASFV对照均扩增出CD2V和MGF360基因片段，而基因缺失病毒没有扩增出相应的缺失基因。
实施例三、病毒滴度的滴定
非洲猪瘟病毒的滴定分别采用半数细胞感染剂量(50％Tissue Culture Infectious Dose，TCID 50)和半数血球吸附量(50％haemadsorption，HAD 50)两种方法进行操作。
TCID 50滴定按照下面步骤进行：将ASFV以无血清1640培养液再作10倍连续稀释，接种培养于96孔培养板、密度约90‐100％‐的PAM细胞，每个稀释度接种8孔，每孔0.02mL,于37℃、5％浓度CO2条件下感作1小时后，每孔再加入含10％胎牛血清的1640完全培养液0.1mL，置37℃、5％浓度CO2条件下培养，观察3-7天，根据细胞病变或绿色荧光和Reed and Muench方法[4]计算半数细胞感染量(TCID 50)。
HAD 50试验根据文献[5]进行操作，并作适当调整：在96孔细胞培养板中接 种原代PBMC，将待检样品进行10倍梯度稀释，每孔接种0.02ml，病毒感染可根据红细胞在感染细胞周围聚集形成的玫瑰花环进行判定，观察7天，根据Reed and Muench方法[Reed,L.and H.Muench,A simple method of estimaing fifty percent endpoints.American Journal of Epidemiology 1938.27:p.493‐497]计算半数血球吸附剂量(HAD 50)
实施例四、动物免疫实验
在中国农业科学院哈尔滨兽医研究所生物安全四级实验动物房中进行引进7周龄大白和长白近交系SPF猪(购自中国农业科学院哈尔滨兽医研究所动物中心)。待猪适应2‐3天后，按照表2‐1进行分组和免疫。此外，设计了脏器病毒分布的试验(表2‐2)。免疫后，持续观察动物的精神状况、采食情况，监测动物体温，采集EDTA抗凝血液和分离血清。
表2‐1试验分组
Figure PCTCN2019084469-appb-000002
表2‐2免疫后脏器分毒试验
Figure PCTCN2019084469-appb-000003
免疫后的体温检测表明(图6)，rASFV△360‐eGFP免疫猪后，不管是高剂量(10 5TCID 50，90‐93号)免疫组还是低剂量免疫组(10 3TCID 50，95‐98号)都没有体温明显升高的现象，存活率100％(图8)；其中90号猪在第16天意外死亡，剖检脏器无明显病变，血液分毒结果为阴性。rASFV△CD2V/360‐eGFP‐mCherry免 疫猪后，不管是高剂量(10 5TCID 50，80‐83号)免疫组、低剂量免疫组(10 3TCID 50，85‐88号)都没有体温升高的现象。此外，同居猪(101和102号)也无体温升高现象。免疫猪和同居猪在免疫后精神状况、采食情况均无异常，无明显临床症状
免疫后血液样品的病毒分离结果表明(表3‐1)，免疫后5、9、14、19天的rASFV△360‐eGFP、rASFV△CD2V/360‐eGFP‐mCherry免疫猪及同居猪均未分离到病毒。
此外，所有rASFV△360‐eGFP、rASFV△CD2V/360‐eGFP‐mCherry免疫猪在免疫后的21天内，各脏器中的病毒分离均为阴性，同时观察期间未发现精神状况、采食情况、临床症状等异常现象(表3‐2)。
综上，rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry两种基因缺失毒株在猪体内充分致弱。
表3‐1 rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry免疫猪后的血液病毒分离检测
Figure PCTCN2019084469-appb-000004
注：“N”表示检测结果为阴性；“/”表示无样品。
Figure PCTCN2019084469-appb-000005
Figure PCTCN2019084469-appb-000006
实施例五、动物攻毒试验
待免疫21天后，rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry免疫组的所有猪进行ASFV强毒攻击，攻击剂量为10 3.5HAD 50，攻毒途径为肌肉注射，同时引进2只8周龄SPF猪作为攻毒对照。攻毒后，持续观察动物的精神状况、采食情况，监测动物体温，采集EDTA抗凝血液和分离血清。
rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry免疫同居猪(101和102号)在攻毒后第11天死亡，而免疫组均在攻毒后存活率100％(图8)，至第21‐22天屠宰剖检。具体体温和血液分毒情况如下所述。
1攻毒后体温变化和临床症状
同居猪(101和102号)在攻毒后，第5‐7天出现体温升高(40.5‐42℃)(图7)、精神沉郁、采食下降等临床症状。
rASFV△360‐eGFP免疫猪在攻毒后，仅有95号猪，第7天体温明显升高，随后回复正常，精神状况和采食情况也恢复正常；其它猪体温、精神状况和采食情况均无异常，均无临床症状。
ASFV△CD2V/360‐eGFP‐mCherry免疫猪在攻毒后，高剂量组(10 5TCID 50)中仅有82号第5天出现一过性体温升高至40.7℃，随后恢复正常；低剂量组(10 3TCID 50)85、87、88号猪均在第5‐11天出现体温一过性升高至41℃以上，随后恢复正常，86号体外稍微偏高，低于41温度。体温升高的猪，精神状况略有萎靡，采食略有下降，但随着体温恢复正常，精神和采食恢复正常，此外无其他明显临床症状。
2攻毒后的血液病毒分离检测
血液病毒分离结果表明(表4)，攻毒后，同居猪(101和102号)在攻毒后第5天病毒分离结果均转阳，并在第7天死亡；而rASFV△360‐eGFP免疫猪攻毒后，仅有2/7猪(91和95号)在攻毒后病毒分离转阳，且在第21天均转为阴性；rASFV△CD2V/360‐eGFP‐mCherry免疫猪攻毒后第5天，8/8猪病毒分离均转阳，但在第22天均转为阴性。这些结果表明，rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry免疫猪均能够对强毒攻击提供充分的免疫保护。
表4 rASFV△360‐eGFP和rASFV△CD2V/360‐eGFP‐mCherry免疫猪攻毒后的血液病毒分离检测
Figure PCTCN2019084469-appb-000007
Figure PCTCN2019084469-appb-000008
注：“+”表示检测结果为阳性；“N”表示检测结果为阴性。

Claims (9)

  1. [根据细则91更正 19.08.2019]　
    一种基因缺失减毒非洲猪瘟病毒，其特征在于，将基因II型的非洲猪瘟病毒的MGF360-505R基因缺失病毒，或CD2V与MGF360-505R基因联合缺失病毒，所述基因II型的非洲猪瘟病毒是全长基因组序列如GenBank:MK333180.1中所述的中国流行株Pig/CN/HLJ/2018。
  2. 根据权利要求1所述的基因缺失减毒非洲猪瘟病毒，其特征在于，所述MGF360-505R基因缺失病毒相对于原始毒株全长序列缺失了第27942-35500位核苷酸。
  3. 根据权利要求2所述的基因缺失减毒非洲猪瘟病毒，其特征在于，所述MGF360-505R基因缺失病毒，保藏号为CCTCC NO:V201925。
  4. 根据权利要求1所述的基因缺失减毒非洲猪瘟病毒，其特征在于，所述CD2V与MGF360-505R基因联合缺失病毒相对于原始毒株全长序列缺失了第27942-35500位和第73394-74476位核苷酸。
  5. 根据权利要求4所述的基因缺失减毒非洲猪瘟病毒，其特征在于，所述CD2V与MGF360-505R基因联合缺失病毒，保藏号为，CCTCC NO:V201924。
  6. 一种非洲猪瘟疫苗，其特征在于，其含有根据权利要求1至5任一项所述的基因缺失减毒非洲猪瘟病毒。
  7. 如权利要求6所述的非洲猪瘟疫苗，其特征在于，先用纳米佐剂生物佐剂，白介素、或干扰素作为佐剂。
  8. 如权利要求6所述的非洲猪瘟疫苗，其特征在于，与其他疫苗制备联合疫苗。
  9. 一种制备根据权利要求1至5任一项所述的基因缺失减毒非洲猪瘟病毒的方法，其特征在于:通过基因工程手段将原始毒株的MGF360-505R基因序列，或 CD2V与MGF360-505R基因序列联合缺失以制备基因缺失减毒非洲猪瘟病毒。
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CN112552396A (zh) * 2020-12-30 2021-03-26 河南中泽生物工程有限公司 抗非洲猪瘟病毒p54蛋白单克隆抗体、制备方法及应用
CN112552396B (zh) * 2020-12-30 2022-07-12 河南中泽生物工程有限公司 抗非洲猪瘟病毒p54蛋白单克隆抗体、制备方法及应用
CN113480642A (zh) * 2021-08-11 2021-10-08 郑州大学 抗非洲猪瘟病毒CD2v蛋白单克隆抗体、制备方法及应用
CN113480642B (zh) * 2021-08-11 2022-06-24 郑州大学 抗非洲猪瘟病毒CD2v蛋白单克隆抗体、制备方法及应用

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