猪瘟、高致病性猪蓝耳病疫苗组合与猪口蹄疫O型灭活苗同时分点免疫效果评价

推广猪瘟、高致病性猪蓝耳病疫苗组合与猪O型口蹄疫灭活苗同时分点免疫（三苗两点同步免疫）技术,免疫45 d后随机对规模养猪场及部分散养户68头猪进行了免疫效果评价.结果表明,三苗两点同步免疫临床上无严重的不良反应,且免疫后抗体有效保护率均达70％以上,该技术可在基层动物防疫中大力推广应用.     

猪口蹄疫O型灭活疫苗PD50效检攻毒剂量试验

采用PD50效检方法,对0304041-2批猪口蹄疫O型灭活疫苗(I型苗)进行不同攻毒剂量的PD50 检测.结果表明,分别用500 ID50 、1 000 ID50 、2 000 ID50 和4 000 ID50 的病毒进行攻毒,疫苗每头份分别含5.2、3.6、2.1和1.0个PD50 .该项试验的攻毒毒株ORMF8的ID50为10-7.0/2 mL,MID为10 -6.0 /2 mL.     

采用蚀斑技术克隆纯化口蹄疫病毒的研究

本研究应用BHK₂₁细胞通过蚀斑试验克隆和再次克隆牛AsiaⅠ型口蹄疫病毒AKT03毒株并对克隆前和第1次、第2次克隆的口蹄疫病毒毒株的细胞半数感染量（TCID₅₀）、乳鼠半数致死量（LD₅₀）进行比较测定,结果表明,通过蚀斑试验成功克隆了牛AsiaⅠ型口蹄疫病毒AKT03毒株,第1次克隆的毒株和第2次克隆的毒株TCID₅₀和LD₅₀效价明显提高。     

口蹄疫免疫与疫苗关系研究进展

免疫是预防口蹄疫的重要理论基础,研究动物机体针对口蹄疫的免疫机理,寻求预防口蹄疫的技术途径,为疫苗研制提供技术支撑。本文主要研究口蹄疫的体液免疫,细胞免疫以及细胞因子在预防口蹄疫方面的重要机理,以及各种口蹄疫疫苗在免疫学方面的优缺点,以便为最大程度的利用其免疫优势,为口蹄疫新苗的设计和防控提供理论依据。     

Quantification of water buffalo (Bubalus bubalis) cytokine expression in response to inactivated foot-and-mouth disease (FMD) vaccine

This study describes the quantification of cytokine expression of vaccinated water buffaloes with FMD inactivated vaccine. Using real-time PCR quantification assay, expression of Th1 (IL-2, IL-12p40, IFNγ); Th2 (IL-4, IL-10) and inflammatory (IL-6, TNFα) cytokines were quantified weekly for the entire three-week duration of the experiment. It was noted that IFNγ, IL-10 and TNFα had peaked on week three post-vaccination while the remaining cytokines peaked on the second week and decreased by the third week. The counteraction between IFNγ and IL-4 was noted as well as the possible suppressive action of IL-10 to that of IL-2 and IL-12, which is a common phenomenon between Th1 and Th2 cytokines. Synergy between TNFa and IL-6 was also observed. These findings suggest that within the immune system of water buffalo there is a dynamic cell-mediated and humoral interaction in response to immunogen. This assessment of the cytokine expressions is vital for the study of water buffalo disease progression and concurring protective immune responses.     

Risk factors for foot and mouth disease seroprevalence in indigenous cattle in Southern Ethiopia: the effect of production system

A serological survey to investigate risk factors for Foot and Mouth Disease (FMD) occurrence was conducted between October 2007 and March 2008 in Southern Ethiopia. Antibodies against non-structural protein of FMD virus (using 3abc ELISA) were measured as indicator of exposure to the virus. The seroprevalence of FMD was 9.5% (95%CI = 7.7 – 11.3, n = 1020) and 48.1% (95% CI = 36.8 – 59.4%, n = 79), respectively at animal and herd levels. Within herd seropositivity was ranged from 6.7 to 46.7% with 18.6% (95%CI = 14.6 – 22.5%) risk of being seropositive for an animal in positive herds. The most important herd level risk factors identified were pastoral system (OR = 16.3, 95% CI = 2.0 -133.7) compared to sedentary, low altitude (OR = 7.5, 95% CI 1.4 -40.7) compared to high altitude, keeping cattle with small ruminants (OR = 5.1, 95% CI 1.0 -25.2) when compared to one species or alone. Seroprevalence was significantly higher (P <0.05) in South Omo than Sidama and Gamo Gofa areas. The odds of seropositivity were 2.8 and 2.3 times higher in the adult (>4 years) and maturing animals (3–4 years) compared to young age category (<3 years). Both multivariable logistic and negative binomial regressions depicted that production system was the major risk factor for FMD seropositivity. Consequently, higher prevalence of FMD in pastoral system where animals are an integral part of life has substantial livelihood and economic implications, which signifies the need for devising control measures.     

携带抗口蹄疫病毒ScFv基因猪成纤维细胞系的建立

根据口蹄疫病毒的感染特征及其在临床发病过程中呈现的症状,筛选抗口蹄疫病毒单链抗体基因。通过EcoRⅠ/NotⅠ双酶切中间质粒pGEX-ScFv获得单链抗体基因片段,并克隆至反转录病毒载体质粒pFB-neo,构建反转录病毒穿梭载体质粒pFB-ScFv。将pFB-ScFv与辅助质粒pVPack-GP、pVPack-10A1共转染HEK293T细胞,包装重组反转录病毒MMLV-ScFv。同时,构建含增强型绿色荧光蛋白基因的重组反转录病毒MMLV-EGFP作为对照。利用所包装重组反转录病毒感染猪成纤维细胞,通过G418筛选获得携带目的基因的单克隆细胞集落。试验结果表明,本试验在成功构建反转录病毒穿梭载体pFB-ScFv和pFB-EGFP的基础上,获得了分别携带抗口蹄疫病毒单链抗体基因和增强型绿色荧光蛋白基因的反转录病毒,并最终筛选出分别携带上述基因的猪成纤维细胞克隆,为抗口蹄疫病毒转基因动物的研究奠定了基础。     

Saponin Adjuvants. Vi. The Adjuvant Activity of Quil a in Trivalent Vaccination of Cattle and Guinea Pigs Against Foot-And-Mouth Disease

The saponin adjuvant Quil A was investigated in trivalent vaccination against foot-and-mouth disease with a concentrated vaccine based on BHK suspension cell virus of the serotypes O, A and G. The activity in cattle was estimated on the basis of seroneutra-lizing antibodies. Five and 10 ml doses with or without 1 mg of Quil A were each injected into 6 animals. Seroneutralizing antibodies were estimated at regular intervals during a period of 29 weeks. The activity in guinea pigs was estimated by experimental challenge. One ml doses of serial 4-fold dilutions of the vaccine with or without 50 µg of Quil A were injected into 24 groups of 20 guinea pigs. Challenge was given 3 weeks after vaccination.It was concluded that Quil A showed adjuvant activity in cattle and guinea pigs with all the serotypes used in the trivalent vaccination.     

应用固相竞争ELISA、液相阻断ELISA和中和试验检测口蹄疫抗体的比较研究

为了评价建立的口蹄疫固相竞争酶联免疫吸附试验(solid phase competition ELISA,SPC-ELISA)方法与传统的中和试验(VNT)和液相阻断酶联免疫吸附试验(liquid phase block ELISA,LPB-ELISA)检测方法之间的关系,本研究对野外采集的不同种类的猪、牛和牦牛共94份血清样品分别进行O型口蹄疫病毒SPC-ELISA、LPB-ELISA和VNT检测,并分别比较3种方法的符合率和阳性检出率。结果表明,建立的O型口蹄疫病毒SPC-ELISA方法与VNT 具有很好的符合率,达88.3%,其中,猪和牦牛血清符合率高达90%和89.5%,阳性检出率为91.2%比LPB-ELISA更符合VNT,因此建立的SPC-ELISA方法比LPB-ELISA方法更符合VNT。     

羊口蹄疫免疫抗体效价高低与免疫时间的关系的试验

根据防制工作需要,在麦积区党川乡的五个羊场进行了绵羊Asia I-O型口蹄疫的区域预防免疫试验。通过监测免疫抗体水平,评价口蹄疫Asia I-O型双价灭活疫苗对绵羊的免疫效果,结果表明,新生羔羊首次免疫后要加强免疫,综合分析认为首次免疫后30d进行加强免疫是合理的。成年羊在有免疫抗体的情况下,接种Asia I-O双价疫苗后,抗体上升,有效保护期可达150d。免疫后150d（5个月）,O型免疫抗体合格率为71.54%,为消除免疫空白期,间隔135d再进行免疫是科学的,根据监测结果分析认为成年羊1年2～3次接种双价疫苗是可行的。