摘要：[目的]构建猪圆环病毒2型(Porcine circovirus 2,PCV2)orf2 DNA核酸疫苗,并评价其免疫效果和安全性。[方法]设计一对特异性引物,扩增PCV2-orf2,利用T载体对其进行克隆,与真核表达载体PcDNA3.1在同等条件下进行双酶切,并进行连接,转化感受态细菌DH5α并克隆,经双酶切鉴定筛选阳性重组质粒,即DNA核酸疫苗,命名为PcDNA3.1-orf2。将该核酸疫苗瞬时转染Vero细胞,通过RT-PCR鉴定其在细胞内的表达情况;并且将该核酸疫苗按100μg.只-1腿部肌肉注射免疫Balb/c小鼠,同时设PBS和PcDNA3.1空载体为对照,免疫2次,间隔2周。分别于首免后第14 d和第28 d采血,用ELISA方法检测其血清抗体。取首免后56 d小鼠的心、肝、脾、肺、肾和脑等实质器官,采用PCR方法检测该核酸疫苗的安全性。[结果]成功地构建了PcDNA3.1-orf2核酸疫苗,在体外Vero细胞中得到了瞬时表达,并且能诱导小鼠产生较强的免疫应答。安全性试验表明该核酸疫苗未整合到小鼠染色体上。[结论]PcDNA3.1-orf2核酸疫苗可以诱导小鼠产生较强的免疫应答,并且是安全的。

摘要：根据GenBank中猪圆环病毒2型orf2基因序列和猪繁殖与呼吸综合征病毒orf5基因序列,分别设计一对引物,应用PCR和RT-PCR扩增出PCV-2 orf2基因和PRRSV orf5基因。将PCR产物orf2经NheⅠ/EcoRⅠ双酶切回收后插入真核表达载体pIRES得到pIRES-orf2,RT-PCR产物orf5经NotⅠ/XbaⅠ双酶切回收后插入pIRES-orf2构建重组质粒pIRES-orf2/orf5。对此质粒中的插入片段,进行PCR RT-PCR及双酶切鉴定,同时对插入序列进行测序分析,表明SD1株orf2与国内多种毒株的同源性为99%,pIRES-orf2orf5转移载体orf5基因的核苷酸推导氨基酸与北美洲原型(VR-2332株)氨基酸同源性为99%。此重组表达载体的成功构建,为进一步研究PCV-2 orf2及PRRSV orf5编码蛋白的生物学活性及研究猪圆环病毒和猪繁殖与呼吸综合征病毒二联核酸疫苗奠定了基础。

摘要：为了建立一种基于SYBRGreen的猪圆环病毒2型(PCV2)荧光定量PCR诊断方法,以PCV2 orf2基因序列为研究对象,构建p MD19T-orf2重组质粒作为阳性标准品,设计特异性引物,对该方法的最适引物浓度、退火进行了优化,并对该方法的灵敏度、特异性、可重复性以及临床样品检出率进行了评价。结果表明,该方法引物的最佳终浓度为0. 2 mol/L,最适退火温度为55℃;检测限可达到3. 0×10~2个拷贝/mL,而普通PCR检测限在3. 0×10~4个拷贝/mL;溶解曲线分析显示,在77~79℃有单一的溶解峰出现,并与CSFV、PPV、PRRSV、PRV没有交叉反应;组内重复性变异系数为0. 29%~0. 32%,组间变异系数为0. 32%~0. 36%;此外,该方法对临床样品的检出率为81. 5%(31/38),而常规PCR为68. 4%(26/38)。因此,相比常规PCR,该方法更为快速、灵敏、特异、稳定,更适合PCV2临床样品的检测,可为该PCV2早期感染的快速检测提供新方法。

摘要：根据GenBank中已发表的猪圆环病毒2型(PCV-2)基因序列,在orf2内设计1对特异性引物,利用PCR反应扩增出371 bp的核酸片段,回收并纯化PCR产物,用地高辛标记,建立了地高辛标记核酸探针诊断PCV-2的方法。该探针与8个PCV-2重组菌的核酸抽提物均能发生特异性杂交,而与对照猪圆环病毒Ⅰ型(PCV-1)、猪繁殖与呼吸综合征病毒(PRRSV)、猪细小病毒(PPV)、猪伪狂犬病病毒(PRV)的核酸杂交均为阴性;对PCV-2 DNA的最低检测量为10 pg。

摘要：根据GenBank中发表的猪2型圆环病毒（PCV2）全基因组序列,设计合成了2对引物,采用PCR方法对来自甘肃不同猪场的3份病料中的PCV2进行基因的扩增、克隆和测序,得到全基因组长度为1 768 bp的PCV2Ww株（登录号DQ322701）以及全基因组长度为1 767 bp的PCV2 LZ株和TS株（登录号DQ363860和DQ355153）.应用DNAstar软件序列分析可得,3个分离株全基因组与国内外参考毒株核苷酸序列同源性在94.8%~99.4%,3个分离株之间的核苷酸序列同源性为96.4%~99.4%;PCV2分离株与PCV1分离株核苷酸序列同源性为69.0%~70.0%;orf1和orf2所编码的氨基酸序列与国内外PCV2毒株比较,同源性也很高,分别为99.0%~99.4%和92.7%~98.7%.进化树分析表明,PCV2分离毒株在进化上存在地域上的相关性.

摘要：为了解河南省猪圆环病毒2型(PCV2)的流行病学情况,参考Gen Bank的PCV2 orf2的序列,设计1对引物,建立PCV2的快速直接PCR检测方法,并进行特异性和敏感性试验。运用该方法对2016年5月至2017年5月采集到的河南省共125份疑似猪圆环病毒2型的病料进行PCV2检测,阳性样品测序,分析河南省PCV2的遗传变异情况。结果显示,建立的PCR检测方法快速、特异、敏感,适用于临床检测或流行病学调查;所检测的125份样品中,55份样品为PCV2阳性,阳性率高达44%。阳性结果序列分析显示,核苷酸序列同源性在88.7%~99.8%,42份在PCV2b基因群。结果表明,河南省PCV2感染率较高,PCV2b为流行血清亚型,病毒变异严重。

摘要：[Objective] In this study, the quantitive detection of PCV2 （porcine circovirus type 2） in vitro was achieved. We aimed to establish two kinds of TaqMan real-time PCR methods based on PCV20RF1 and orf2 respectively and compare them. [Method] According to the relatively＇conserved sequences of PCV20RF1 and orf2 registered in GenBank, two pairs of specific primers and TaqMan probes were designed and synthesized. Then the recombinant plasmids containing the whole sequences of PCV20RF1 and orf2 were constructed to draw the standard curves through optimizing the reaction system and conditions. And thus two kinds of TaqMan real-time PCR detection methods based on the whole sequences of orf1 and orf2 respectively were constructed for PCV2. [Result] For the two established standard curves, the Ct values showed a good linear relationship with the loga- rithms of copy numbers of templates （F2〉0.99）. The amplification efficiency ranged from 90% to 110%. The amplifications all had a good repeatability with variation coefficients within groups all less than 5%. Moreover, the amplifications all had a good specificity. When the sequences of porcine parvovirus （PPV）, porcine circovirus type 1 （PCV1）, swine pseudorabies virus （PRV）, porcine reproductive and respiratory syndrome virus （PRRSV） were used as templates, the target sequence was not amplified. The amplifications also had a high sensitivity. The orf1 detection method could reach 1.0x10T copies/;ul, and the orf2 detection method could reach 1.0×10^2 copies/μl. The two established real-time PCR detection methods were used to detect the 80 clinical samples respectively. The results showed the magnitudes of 72 amplified samples were basically consistent between the 2 detection methods, while the magnitudes of the other 8 amplified samples were inconsistent. Then the 8 samples were detected with SYBR Green I real-time PCR method established based on the sequence of PCV2-1ike factor P1 by Wen et aL The PCV2-1ike factor P1 was ampl