禽白血病/肉瘤病毒群特异性抗原p27的分离纯化及其抗体的制备

采用细胞培养法增殖禽白血病/肉瘤病毒(ALV/RSV)A亚型,然后对其进行超速离心浓缩及蔗糖密度梯度离心纯化病毒,再采用电泳分离与电洗脱收集相结合的方法纯化p27蛋白.经检测,提取的p27蛋白具有良好的抗原性与免疫原性.用该蛋白免疫家兔制备的兔抗p27抗体,经ELISA方法检测其效价可达1:6400以上.     

禽白血病病毒p27蛋白在大肠杆菌中的表达和多克隆抗体的制备

将禽白血病病毒p27基因克隆并构建重组表达质粒pET28a-p27,在大肠杆菌BL21中经IP TG诱导后产生可溶性表达蛋白。表达的蛋白用Western blot进行活性检测,其能与辣根过氧化物酶标记的兔抗p27抗体发生特异性反应;采用金属螯和层析对表达蛋白进行纯化,其纯度约为95％;用纯化的表达蛋白p27免疫家兔制备抗血清,ELISA抗体效价可达1∶25600。研究结果表明,大肠杆菌表达的p27蛋白具有良好的抗原性,可以替代纯化病毒蛋白用于禽白血病病毒检测。     

禽白血病病毒群特异性抗原单克隆抗体的制备与鉴定

为制备禽白血病病毒(ALV)群特异性抗原的单克隆抗体(MAb),本研究从ALV-J病毒株感染DF-1细胞的冻融裂解液中提取DNA,通过PCR方法扩增出ALV群特异性抗原p27基因,并将其克隆至pMD18-T载体中,酶切鉴定后进行序列测定和分析。最后将p27基因亚克隆至载体pET-30a(+)中,转化受体菌BL21,IPTG诱导表达,经SDS-PAGE检测获得融合蛋白。经过western blot检测,表达的蛋白具有良好的反应原性。将纯化的p27蛋白作为抗原,免疫7周龄BALB/c小鼠,利用淋巴细胞杂交瘤技术,获得5株能稳定分泌特异性MAb的杂交瘤细胞株。5株MAb与纯化的p27蛋白以及不同亚群ALV可以发生特异性反应。所制备的MAb为禽白血病的诊断方法研究奠定了基础。     

非洲猪瘟病毒p11.5蛋白的表达及其单克隆抗体的制备

为了制备非洲猪瘟病毒(African swine fever virus, ASFV)p11.5蛋白的特异性单克隆抗体,利用大肠杆菌表达系统,将密码子优化后的ASFV p11.5基因序列连接表达载体pET28a-SUMO,构建pET28a-SUMO-p11.5原核表达质粒,获得了可溶性的ASFV p11.5蛋白。经Western blot鉴定,重组ASFV p11.5蛋白可被ASFV标准阳性血清特异性识别,表明其具有良好的反应原性。将纯化后的p11.5蛋白免疫BALB/c小鼠,通过杂交瘤细胞法,制备了4株可稳定分泌抗ASFV p11.5蛋白单克隆抗体的杂交瘤细胞株。3株单克隆抗体重链亚类为IgG1,1株重链亚类为IgG2a,轻链亚类均为κ。采用p11.5蛋白为包被抗原的间接ELISA方法检测单克隆抗体的效价均不低于1∶102.4×10~4。经间接免疫荧光试验(IFA)鉴定,4株单克隆抗体,均不与猪瘟病毒、猪繁殖与呼吸综合征病毒、猪伪狂犬病病毒、猪圆环病毒2型、猪流行性腹泻病毒发生交叉反应,但均能与ASFV反应,表明单克隆抗体具有良好的特异性和反应性。本试验为p11.5蛋白结构功能、免疫学特性及ASFV诊断试剂产品的研究提供了重要的生物材料。     

禽成髓性白血病病毒p27和gag基因的克隆

禽成髓性白血病是由禽成髓性白血病病毒引起的一种禽白血病（Avian Leukosis)。禽成髓性白血病病毒的gag基因具有高度保守性，其编码的群特异性抗原p27是禽白血病病毒所共有的主要核心蛋白，可做为禽白血病的诊断抗原。本实验采用AMV感染鸡胚成纤维细胞（CEF），提取感染细胞总RNA，用随机引物反转录成cDNA，根据已经发表的AMV BAI－A株序列设计两对针对p27基因和gag基因的特异性引物，分别进行PCR，成功地扩出p27基因和gag基因，其片段分别为793bp和2．1Kb。以gag基因的PCR产物为模板，采用p27的特异性引物也成功扩出p27片段。分别将p27,gag基因与pGEM－TEasy载体进行连接，转化大肠杆菌，筛选阳性克隆，提取质粒，进行酶切鉴定。对含有p27基因的质粒进行测序，结果证明成功克隆了p27基因，间接证明了2．1Kb的片段是gag基因。p27和gag基因的成功克隆为该病的探针诊断和gag基因的表达提供了基础。     

非洲猪瘟病毒B318L蛋白的多克隆抗体的制备及应用

非洲猪瘟病毒(ASFV) B318L是ASFV编码的晚期蛋白，具有香叶基香叶基合成酶活性。为了制备B318L的多克隆抗体并将其初步应用，本研究利用PCR方法从重组质粒p CAGGS-HA-B318L中扩增ASFV B318L基因构建重组表达质粒p GEX-6p-1-B318L，经PCR和测序鉴定正确后转化大肠杆菌BL21 (DE3)经IPTG诱导并克隆至p GEX-6p-1载体中，采用GST亲和层析柱纯化重组蛋白，利用SDS-PAGE检测该蛋白的表达，采用western blot鉴定重组蛋白的纯化效果和反应原性，采用超微量紫外分光光度计测定蛋白浓度。结果显示，在约60 ku处出现特异性条带，且重组B318L蛋白(rB318L)主要以可溶性形式表达；纯化后在约60 ku处出现了单一特异性条带，经超微量紫外分光光度计测定蛋白浓度为10 mg/m L。将纯化的r B318L 4次免疫小鼠并于3免后一周采血，采用western blot鉴定该多克隆抗体(pAb)，经Protein G亲和层析介质纯化后采用SDS-PAGE进一步鉴定纯化效果，采用间接ELISA检测p Ab的效价。结果显示，制备的...     

禽白血病病毒衣壳蛋白p27基因的原核表达及多克隆抗体的制备

从J亚群禽白血病病毒(ALV-J)HB09JY03株感染的DF-1细胞的冻融裂解液中提取DNA,通过PCR方法扩增出约720bp的gag-p27基因片段,克隆至pMD18-T载体。鉴定正确后,将该片段克隆至pET-30a(+)原核表达载体,经IPTG诱导表达。表达产物经His Trap TMHP纯化后,测蛋白浓度达到9mg/mL。用兔抗自然p27蛋白阳性血清进行Western blot检测,表明重组p27蛋白有抗原反应活性。免疫新西兰大白兔后,产生的抗体与禽白血病全病毒抗原可以发生特异性反应。所制备的重组p27蛋白和多克隆抗体将在ALV的抗原分析、血清学诊断等方面有着重要的应用价值。     

非洲猪瘟病毒p17蛋白的哺乳动物细胞表达及鉴定

研究旨在利用哺乳动物细胞悬浮培养系统表达非洲猪瘟病毒(ASFV)p17蛋白,纯化并免疫小鼠,制备针对ASFV p17蛋白的特异性多克隆抗体。根据GenBank中公布的ASFV SY18毒株p17蛋白编码基因序列,设计特异性引物扩增p17基因片段,构建重组真核表达质粒pCDNA3.1-p17-strep。将其瞬时转染293i细胞,并利用下游strep标签进行蛋白纯化。纯化后的重组p17蛋白配合MnJ(β)胶体锰佐剂免疫BALB/c小鼠制备多克隆抗体血清。利用Western blot、间接免疫荧光试验鉴定该多克隆抗体的反应原性和特异性。结果显示：本试验成功构建pCDNA3.1-p17-strep真核表达质粒,转染293i细胞后纯化获得重组p17蛋白。免疫小鼠后制备的多克隆抗体与真核表达的p17蛋白及表达ASFV p17蛋白的猪繁殖与呼吸综合征病毒均有良好的特异性免疫反应。本试验为深入探讨ASFV p17蛋白的生物学功能奠定了基础。     

山羊痘病毒p32基因的克隆、表达及单克隆抗体制备

本研究旨在表达山羊痘病毒p32蛋白、制备p32蛋白单克隆抗体。通过PCR克隆p32基因,连接到pMD18-T并测序;酶切、连接后将p32基因克隆到pET28a(+)中,将重组质粒转化大肠杆菌Rosseta,在IPTG诱导下成功表达p32蛋白;利用亲和层析法纯化p32蛋白,用纯化蛋白免疫BALB/c小鼠后制备p32蛋白单克隆抗体,获得22株识别重组蛋白的单抗,通过间接免疫荧光鉴定,其中3株能识别病毒的p32蛋白。山羊痘病毒p32蛋白的表达和单克隆抗体的制备为山羊痘病毒抗原、抗体检测提供了生物材料。     

非洲猪瘟病毒p54蛋白单克隆抗体制备及其抗原表位鉴定

旨在制备非洲猪瘟病毒(ASFV)p54蛋白的特异性单克隆抗体。本研究利用大肠杆菌表达系统表达p54蛋白,免疫BALB/c小鼠,取其脾细胞与SP2/0细胞进行细胞融合。利用纯化的p54蛋白作为包被抗原,采用间接ELISA方法筛选获得阳性杂交瘤细胞。经4次亚克隆后,取杂交瘤细胞上清进行单克隆抗体亚型鉴定,利用体内诱生法制备单克隆抗体并进行纯化。间接ELISA方法检测单克隆抗体的效价,利用交叉反应性试验、间接免疫荧光试验和蛋白印迹对所获单克隆抗体的特异性进行鉴定。根据预测的p54蛋白二级结构,采用逐步截短法分析鉴定单克隆抗体识别的抗原表位区域,并在p54的三级结构中进行标注。结果显示：成功筛选了6株分泌p54单克隆抗体的杂交瘤细胞,分别命名为28G12-1、31G7-1、31G7-2、35F10-1、35F10-2、38D3-1。其中28G12-1、31G7-1、31G7-2重链为IgG2a型,35F10-1、35F10-2、38D3-1重链为IgG1型;轻链均为κ链。单克隆抗体的最低效价为1∶25 600,与猪繁殖与呼吸综合征病毒、猪伪狂犬病病毒、猪流行性腹泻病毒、猪细小病毒、猪急性腹泻综...     

细胞周期蛋白激酶抑制因子p27Kipl研究进展

p27 Kipl基因是近年来新发现的一种抑癌基因,其编码的p27Kipl蛋白为细胞周期素依赖性蛋白激酶抑制因子(CDKI),在调控细胞周期中具有十分重要的作用.p27蛋白表达下调与恶性肿瘤细胞的异常增殖、癌变关系密切.研究还发现p27基因及其表达产物对于肿瘤患者的预后、指导肿瘤治疗及调节机体生长发育方面也有着十分重要的...     

Immunohistochemical detection of p27 and p21 proteins in canine hair follicle and epidermal neoplasms

Trichoblastomas, trichoepitheliomas, and squamous cell carcinomas in the skin of dogs were analysed by immunohistochemistry for the nuclear expression of p27, p21 and proliferating cell nuclear antigen (PCNA). High levels of p27 were present in trichoepitheliomas and trichoblastomas compared with squamous cell carcinomas. Detectable p21 was found in trichoepitheliomas and squamous cell carcinomas, but trichoblastomas had low level of p21 nuclear reactivity. Low levels of PCNA were detected in trichoepitheliomas and trichoblastomas compared with squamous cell carcinomas. The results suggested that nuclear p27 acts as a cyclin-dependent kinase (CDK) inhibitor in trichoepitheliomas and trichoblastomas. Nuclear p21 expression is involved in the induction of epithelial differentiation and seems to be unrelated to CDK inhibition.     

Immunohistochemical expression of p27 and p21 in canine cutaneous mast cell tumors and histiocytomas

The objective of this study was to evaluate by immunohistochemical means the nuclear expression of p27 and p21 proteins in cutaneous mast cell tumors and histiocytomas of dogs. In mast cell tumors, nine of the 13 grade I tumors, 13 of the 19 grade II tumors, and 10 of the 15 grade III tumors showed no detectable or mild p27 immunoreactivity. In contrast, one of the 13 grade I tumors, 12 of the 19 grade II tumors, and 11 of the 15 grade III tumors showed moderate or marked p21 immunoreactivity. Nineteen of the 28 histiocytomas showed no detectable or mild p27 immunoreactivity, and 24 cases showed moderate or marked p21 immunoreactivity. These findings indicate that a loss or absence of p27 expression is an early pathogenic event in mast cell and histiocyte tumorigenesis and that p21 expression may be a marker of mast cell tumor progression and histiocytoma cell proliferation.     

Absence of p21 WAF1 and p27 Kip1 Gene Mutations in Various Feline Tumours

The coding regions of tumour suppressor and cell cycle regulatory genes p21 WAF1 and p27 Kip1 were investigated in 101 feline tumours of various types. No damaging mutations were present in the analysed areas of the genes     

猴D型逆转录病毒P27基因的表达、纯化及重组蛋白的鉴定

根据GenBank上已发表的猴D型逆转录病毒SRV-2株基因组序列设计合成了一对特异性引物,通过PCR扩增出P27基因。将扩增出的片段克隆到原核表达载体pBAD/Thio-TOPO上,通过序列分析证实该片段与猴D型逆转录病毒SRV-2株P27基因序列一致。将阳性重组质粒转化至大肠杆菌T0P010中,用阿拉伯糖诱导表达,表达的融合蛋白进行SDS-PAGE和WesternBlot分析,并用proBondTM柱在天然状态下进行纯化。结果表明,表达的融合蛋白分子量约为50KDa,其大小与预期相符。     

SIVp27抗原双抗体夹心ELISA检测方法的研究

目的建立检测SIVp27抗原的双抗体夹心ELISA方法并进行初步应用。方法使用ProteinA亲和层析柱纯化腹水中的SIVp27单抗,用过碘酸钠法对单抗进行辣根过氧化物酶标记。经抗体配对实验确定包被抗体和检测抗体,再用棋盘滴定法确定抗体工作浓度后,探索构建检测SIVp27抗原的双抗体夹心ELISA法。应用建立的双抗体夹心ELISA法,对SIV模型猴血浆标本和SHIV模型猴病毒分离培养上清标本进行了检测,并将其结果与Coulter公司试剂盒检测结果进行比较。结果以稀释至20ug/mL的2E12为包被抗体、1:400稀释的酶标3G3为检测抗体为ELISA最优体系。模型猴血浆标本和病毒分离培养上清标本的检测结果表明自建体系可以用于SIVp27抗原的检测,特异性良好,灵敏度略低于Coulter公司试剂盒。结论检测SIVp27抗原的双抗体夹心ELISA方法初步建成,为研制有独立知识产权的检测试剂奠定了一定的基础。     

Loss of p27 expression in canine mammary tumors and their metastases

The p27 gene is a member of the cyclin-dependent kinase inhibitors, which arrest G1- to S-phase transition of the cell cycle. We have previously shown a significant reduction of p27 mRNA expression level in laser-microdissected mammary carcinomas and their lymph node metastases when compared to non-neoplastic mammary gland of the same dog. Here, p27 expression was analyzed on the protein level in non-neoplastic mammary gland, primary mammary carcinomas, their lymph node metastases and intravascular tumor cells of 49 dogs, adenomas of 49 dogs and non-neoplastic mammary gland of 98 dogs by immunohistochemistry. A significantly (p ? 0.05) decreased percentage of p27 positive tissue samples was found when normal gland was compared with adenomas, carcinomas and lymph node metastases. Specifically, 91% of normal gland epithelium displayed nuclear p27 expression. In contrast, only 22% of the adenomas, 20% of carcinomas, 12% of lymph node metastases and 32% of intravascular tumor cells had p27 reactivity. Cell cycle control by p27 is therefore lost in the majority of canine mammary tumors. The lack of significant differences between benign and malignant mammary tumors indicates that decreased p27 expression is an early step in carcinogenesis of canine mammary tumors and hinders the use of p27 as a marker of malignancy for this tumor type.     

Differential expression of cell cycle regulators p21, p27 and p53 in metastasizing canine mammary adenocarcinomas versus normal mammary glands

The cyclin dependent kinase inhibitors p21 and p27 are important regulators of cell cycle progression. To analyze their role in the malignant progression of canine mammary tumors expression levels of p27 and p21 and its major regulator p53 were compared in simple adenomas, adenocarcinomas of the mammary gland and lymph node metastases with normal mammary gland. Laser microdissection of tissue samples and real-time PCR were used for quantification of mRNA expression levels. p21 was overexpressed in adenocarcinomas, whereas adenomas and metastases expressed p21 more heterogeneously. Comparison of p21 expression in adenocarcinomas and their metastases revealed a significant decrease in expression in metastases. In contrast, p27 expression was reduced in the adenocarcinomas but heterogeneously expressed in adenomas and metastases. Taken together the results suggest that loss of p21 overexpression is associated with tumor metastasis while reduced cell cycle inhibition by p27 is associated with malignant progression.