幽门螺杆菌鞭毛蛋白A单克隆抗体的制备与鉴定

幽门螺杆菌(Helicobacter pylori)鞭毛蛋白A(FlaA)可作为临床诊断标志物,但目前尚无识别FlaA蛋白的特异性抗体.该研究构建了HpflaA基因表达质粒,表达并纯化了HpFlaA重组蛋白,并以此重组蛋白为抗原免疫BALB/c小鼠,通过杂交瘤细胞技术制备HpFlaA单克隆抗体,最后对抗体的亚型、效价、纯度、亲和力和特异性等进行鉴定.共获得5株能稳定分泌单克隆抗体的杂交瘤细胞株,分别命名为2G2、2G10、3E2、3E4和4H3.这5株细胞分型均为IgG1型且抗体效价均超过1∶10~5,亲和常数均达到10~7以上.经间接酶联免疫吸附实验和蛋白质免疫印记实验验证,单克隆抗体能特异性识别HpFlaA.成功制备出高亲和力、高效价、特异性好的HpFlaA单克隆抗体,具有潜在临床应用价值.     

重组人血管内皮生长因子(VEGF)单克隆抗体的制备

为制备人血管内皮生长因子(VEGF)单克隆抗体,制备并纯化了VEGF蛋白,通过免疫、细胞融合、筛选等方法获得了能够稳定分泌单克隆抗体的细胞株;采用小鼠腹腔接种法制备腹水,并用G蛋白(Protein G)亲和层析柱对抗体进行了纯化;采用间接ELISA及Western blot实验分别对纯化后的抗体进行了效价测定和特异性验证.结果表明:此方法可成功筛选出能稳定分泌VEGF单克隆抗体的杂交瘤细胞株,纯化后腹水抗体效价为1∶1 024;Western blot检验证实制备的单克隆抗体能特异性识别VEGF蛋白.     

抗人骨桥蛋白单克隆抗体制备及其特异性研究

利用RT-PCR技术克隆人骨桥蛋白(hOPN)基因,构建OPN原核表达质粒pET-32a(+)-hOPN,转化BL21菌株,经IPTG诱导表达重组人骨桥蛋白(rhOPN).以纯化的rhOPN为免疫原,免疫BABL/c小鼠,取其脾细胞与小鼠骨髓瘤细胞NS1融合.通过有限稀释法进行克隆和间接ELISA筛选,获得抗人OPN蛋白单克隆抗体杂交瘤细胞株,以ELISA、Western blot对抗体特异性进行鉴定.通过竞争抑制试验对单克隆抗体识别抗原位点进行分析.结果共获得2株抗人OPN单克隆抗体,分别命名为8F1和2B5,亚型测定皆为IgG1.通过细胞侵袭抑制试验检测,2株抗人OPN mAb皆能很好地抑制细胞迁移.本研究成功获得了抗人骨桥蛋白的特异性单克隆抗体,为进一步研究OPN蛋白在自身免疫病和肿瘤中的功能提供了重要的工具.     

DSCR1抗体制备与应用

本实验利用Fmoc固相多肽合成的方法合成DSCRI氨基端一个多肽片段(55-70AA),经HPLC纯化后偶联到匙孔槭血蓝蛋白,免疫新西兰雄兔后采血检测、纯化、经Westem blotting、免疫沉淀证实得到的抗体为抗DSCR1的特异抗体。谊抗体即能检测人源DSCR1蛋白,又能检测小鼠的DSCR1蛋白。运用获得的DSCR1多克隆抗体进行功能研究。发现DSCR1广泛存在泛素化,参与泛素化-蛋白酶体途径。     

长型肌球蛋白轻链激酶4Ig结构域的表达及单克隆抗体的制备

长型肌球蛋白轻链激酶(long myosin light chain kinase,L-MLCK)及其分子内结构域的功能还不清楚.在研究其功能时,特异性抗体是一基本工具,但目前国际上还没有制备成功特异性较好的抗体.为此,我们先在大肠杆菌E.coliBL21中重组表达了鸡L-MLCK的4Ig蛋白片段(MLCK4Ig),蛋白经纯化后作为抗原免疫小鼠.在小鼠血清中检测到特异性抗体的基础上,建立了2株杂交瘤细胞株,获得抗鸡MLCK4Ig的单克隆抗体.该抗体可以特异与鸡L-MLCK和鸡MLCK4Ig反应.本文并对该抗体的特性及应用进行了讨论.结果表明,我们部分解决了L-MLCK的抗体缺乏问题,为研究L-MLCK及MLCK4Ig片段的功能提供了重要工具.     

酵母(Saccharomyces cerevisiae)Sch9蛋白激酶PDK1位点体内磷酸化的研究

根据Sch9氨基酸序列中激活区570位苏氨酸（T570）位点，也被称为PDK1位点附近的氨基酸序列设计了一段磷酸化多肽，并获得了570位磷酸化苏氨酸特异性抗体. 实验表明该抗体可有效区别Sch9 PDK1位点的磷酸化和非磷酸化. 使用该抗体检测生理条件下表达的Sch9蛋白，发现Sch9的PDK1位点在生理条件下发生了明显的磷酸化.     

GFAP单克隆抗体制备及ELISA检测方法研究

制备抗胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)单克隆抗体,并尝试建立双抗夹心ELISA检测方法,为出血性脑卒中早期诊断提供基础材料.用重组人GFAP作为抗原免疫BALB/C小鼠,通过杂交瘤技术制备抗GFAP单克隆抗体;用HRP标记单克隆抗体,ELISA和Western blot检测抗体的亚类、表位和特异性;采用ELISA技术制备GFAP检测试剂盒.获得了7株抗GFAP单克隆抗体,抗体亚类为Ig G2或Ig G1,抗体特异性好.抗体配对成功,ELISA检测重组人GFAP灵敏且稳定.     

从单个兔B细胞获得抗人cGAS蛋白单克隆抗体

为研究环鸟苷酸-腺苷酸合成酶入核的机制,利用兔外周血B细胞筛选抗人cGAS蛋白单克隆抗体.针对已三次免疫人cGAS(161-522)蛋白的新西兰兔,运用流式细胞术得到阳性效应B细胞,在单管里对单细胞裂解,得到总RNA,逆转录生成cDNA,两步巢式PCR扩增同一个B细胞来源的抗体重链和轻链可变区序列,抗体基因扩增成功率高达80%以上.293T重组表达兔抗人cGAS蛋白单克隆抗体并鉴定,获得1个具有较好结合特异性的兔抗人cGAS蛋白单克隆抗体,ELISA检测结果显示抗体的效价达1∶10 000.     

VMP1基因的克隆及其抗体的制备与鉴定

为了得到效价高、特异性强、能用于检测内源性 VMP1 蛋白的抗体,采用RT-PCR 法,从L929细胞株中克隆鼠VMP1基因,重组入pCMV5载体,用 PCR 扩增与其氨基酸 132-239 区域对应的DNA片断,将该片段连接到原核表达载体 pGST parallel 中,在大肠杆菌 BL21 菌株中大量表达,经谷胱甘肽-琼脂糖树脂纯化后,得到高纯度的 VMP1抗原.免疫新西兰兔,获得抗 VMP1 蛋白的兔抗血清,将血清纯化后即得到抗 VMP1 的多克隆抗体.用 Western blot 分析手段检测了该抗体的特异性及效价.在用该抗体检测外源性和内源性 VMP1 蛋白的试验中,证实该抗体效价高,特异性强,效果很理想.此方法可用于获得大量廉价的抗 VMP1 蛋白的高滴度和高特异性的抗体,为进一步研究 VMP1 在细胞内,尤其是在信号转导通路中的功能和作用奠定了基础.     

抗人FXYD6单克隆抗体的制备及鉴定

制备了抗人FXYD6单克隆抗体,并进行初步鉴定.以FXYD6合成多肽作为免疫原,利用单克隆抗体杂交瘤技术建立阳性克隆细胞株;腹水诱导法制备抗人FXYD6单克隆抗体;蛋白A亲合层析法纯化;ELISA测定FXYD6单克隆抗体的特异性和效价;以所得特异性抗体为一抗,利用免疫组化法检测胰腺癌组织中FXYD6的表达.结果成功获得1株稳定分泌特异性抗人FXYD6单克隆抗体的杂交瘤细胞株;腹水诱导法生产抗人FXYD6单克隆抗体2.86 mg;FXYD6单克隆抗体可以与FXYD6合成多肽特异性结合,抗体效价1:5400;免疫组织化学显示胰腺癌组织中胞膜呈阳性染色.成功获得FXYD6单克隆抗体可以为进一步研究FXYD6的组织分布、生物学作用创造条件.     

Smurf攻击及其对策研究

Smurf攻击为DDoS攻击中较为常见的一种。该攻击方式利用TCP／IP协议自身的缺陷，结合使用IP欺骗和ICMP回复方法，使网络因响应ICMP回复请求而产生大量的数据流量，导致网络严重的拥塞或资源消耗，引起目标系统拒绝为合法用户提供服务，从而对网络安全构成重大威胁。该文在分析了这种攻击实施的原理的基础上，提出这种攻击的检测方法和防范技术。     

DNA damage stress induces the dissociation of Smurf1/2 from MDM2 in a slow manner

The tumor suppressor p53 locates at the key point of cell growth or apoptosis balance, and the expression level of p53 is tightly controlled by ubiquitin ligases including MDM2. Upon DNA damage stresses, p53 was accumulated and activated, leading to cell cycle arrest or apoptosis. We previously showed that Smad ubiquitylation regulatory factor 1/2 (Smurf1/2) promotes p53 degradation by interacting with and stabilizing MDM2, and consequently enhancing MDM2-mediated ubiquitylation of p53. However, it is uncle...     

Molecular cloning and characterization of an insulin-regulatable glucose transporter

A major mechanism by which insulin stimulates glucose transport in muscle and fat is the translocation of glucose transporters from an intracellular membrane pool to the cell surface. The existence of a distinct insulin-regulatable glucose transporter was suggested by the poor cross-reactivity between antibodies specific for either the HepG2 or rat brain glucose transporters and the rat adipocyte glucose transporter. More direct evidence was provided by the production of a monoclonal antibody (mAb 1F8) specific for the rat adipocyte glucose transporter that immunolabels a species of relative molecular mass 43,000 (43K) present only in tissues that exhibit insulin-dependent glucose transport, suggesting that this protein may be encoded by a different gene from the previously described mammalian glucose transporters. This antibody has been used to immunoprecipitate a 43K protein that was photoaffinity-labelled with cytochalasin B in a glucose displaceable way, and to immunolabel a protein in the plasma membrane of rat adipocytes, whose concentration was increased at least fivefold after cellular insulin exposure. Here we describe the cloning and sequencing of cDNAs isolated from both rat adipocyte and heart libraries that encode a protein recognized by mAb 1F8, and which has 65% sequence identity to the human HepG2 glucose transporter. This cDNA hybridizes to an mRNA present only in skeletal muscle, heart and adipose tissue. Our data indicate that this cDNA encodes a membrane protein with the characteristics of the translocatable glucose transporter expressed in insulin-responsive tissues.     

B19 单倍型鸡 BNK 蛋白单克隆抗体的制备

摘要: 目的 体外构建稳定表达鸡自然杀伤细胞( Natural killer,NK) BNK 蛋白的细胞系,制备 BNK 蛋白的单克隆抗体,为鸡 BNK 蛋白及 NK 细胞的研究提供便利。方法 利用 BNK19 原核表达产物免疫 BALB/c 小鼠,体外稳定表达疫病敏感性 B19 单倍型鸡 BNK 蛋白( BNK19) 的真核细胞系筛选单克隆抗体。结果 用稳定表达 BNK 蛋白的真核细胞系筛选到 2 株 BNK19 特异性单克隆抗体。结论 获得的单克隆抗体经鉴定具有免疫学活性,为鸡 BNK 蛋白及 NK 细胞的作用机制研究提供了条件。     

DNA damage stress induces the dissociation of Smurf1/2 from MDM2 in a slow manner

The tumor suppressor p53 locates at the key point of cell growth or apoptosis balance, and the expression level of p53 is tightly controlled by ubiquitin ligases including MDM2. Upon DNA damage stresses, p53 was accumulated and activated, leading to cell cycle arrest or apoptosis. We previously showed that Smad ubiquitylation regulatory factor 1/2 (Smurf1/2) promotes p53 degradation by interacting with and stabilizing MDM2, and consequently enhancing MDM2-mediated ubiquitylation of p53. However, it is unclear how the Smurf1-MDM2 interaction is regulated in response to DNA damage stress. Here, we show that in response to etoposide treatment Smurf1 dissociates from MDM2, resulting in MDM2 destabilization and p53 accumulation. The negative regulation of Smurf1 on apoptosis is released. Notably, this dissociation is a slow process rather than a rapid response, implicating high expression of Smurf1 might confer the resistance against p53 activation. Consistent with this notion, we observed that Smurf1/2 ligases are highly expressed in colon cancer, esophageal squamous cell carcinoma and pancreatic cancer tissues, suggesting the oncogenic tendency of Smurf1/2.     

去除血清诱发细胞凋亡和Bcl—2蛋白的裂解

以过表达原癌基因Bcl-2的HL－60细胞为材料,通过去除血清而诱发凋亡,应用Western blot方法检测细胞凋亡过程中Bcl-2裂解为分子量大约为20kDa的片段,进一步检测Bcl-2的结构变化,结果显示Bcl-2蛋白裂解发生在N端,裂解产物丢失了BH4结构域。通过加入凋亡相关蛋白酶caspase-3抑制剂,可抑制20kDa片段的产生,表明凋亡过程中caspase-3的激活,但细胞生长率测定表明,caspase-3抑制剂并不能阻止去血清诱发的细胞死亡。     

Inhibition of antigen-induced T-cell clone proliferation by antigen-specific antibodies

Attempts to inhibit the recognition of soluble antigens by T lymphocytes using antibodies specific for the antigen in question have been uniformally unsuccessful, in contrast to the observed specific inhibition of antibody generation by B cells. One exception is the unique situation whereby anti-hapten antisera inhibit the T-cell proliferative responses observed when hapten-specific T lymphocytes or clones are cultured with hapten-derivatized cells or proteins. The inability to inhibit T-cell functions by antigen-specific antibodies has been interpreted in several ways: (1) T cells possess a different repertoire from B cells; (2) the antibodies tested recognize epitopes present on the native antigen, whereas T cells recognize non-native (processed) structures; (3) the antigenic determinant(s) recognized by T cells on the surface of antigen presenting cells are either not accessible to antibodies, or are present in low amounts. The development of antigen-specific T-cell clones and monoclonal antibodies both specific for the same antigenic determinants now allows this question to be investigated definitively. Here, we report for the first time the specific inhibition of antigen-induced T-cell clone proliferation by a monoclonal antibody directed against the relevant soluble protein antigen.     

人和小鼠神经干细胞的体外培养的分化研究

首次克隆了小鼠神经元标志性微管蛋白βⅢ基因，从核苷酸序列推导出小鼠与人两者之间在其羧基端有相同的EAQGPK六肽，进一步证实用抗人微管蛋白βⅢ单抗可检测小鼠神经干细胞分化成的神经元细胞，免疫组化鉴定显示小鼠神经干细胞在体积分数为1％胎牛血清（FBS）诱导下，可分化成神经元，星形胶质细胞，少突胶质细胞，同时培养了13周龄胎儿脑来源的人类神经干细胞，用特异性的抗人nestin抗体鉴定，全部为阳性细胞，但它们经诱导分化产生较不同寻常的细胞分化细胞和分化程度，在生长因子减半和1％FBS诱导条件下可分化为神经元和星形胶质细胞，而无少突胶质细胞分化，NF单抗检测证实为早期分化的神经元。