Preparation of Monoclonal Antibody Against HPT and Its Application to Detecting Marker Protein in Genetically Modified Rice

To produce the monoclonal antibodies （mAbs） against hygromycin B phosphotransferase （HPT） and to develop immunoassay based on mAbs for biosafety assessment of HPT in genetically modified rice （GM rice）. Methods BALB/c mice were immunized with purified recombinant 6His. HPT protein, and the conventional hybridoma technology was used to generate the monoclonal hybridoma cells. ELISA and Western blot were used to analyze the specificity of mAbs recognizing HPT and the cross reaction with other proteins. A double-Ab sandwich ELISA method was established to detect HPT expression level in the sck gene-modified rice plants. Results Four hybridomas, named F1,D4-2, D4-4, and D4-5, producing the mAbs against HPT were successfully obtained with the titer of ascetic mAbs ranging from 10×10^-4 to10×10^-5. Identification of subclass showed that all the produced mAbs belonged to IgG1. Western blot showed specific binding reaction between the mAbs to the HPT proteins expressed in the GM rice. A double sandwich ELISA coated with anti-HPT polyclonal antibody was established with mAbs as sandwich antibody, which showed a sensitivity of 30ng/mL and did not crossreact with other proteins. The expression level of HPT in the leaves of sck-transformed lines was detected （80-150ng/mL）. But HPT protein in the grain and seed of GM rice could not be detected using this ELISA assay, Conclusion Anti-HPT mAbs prepared herein have a high specificity and can be used for rapid assay of HPT antigen. The expression level of HPT in the GM rice grain and seed is lower than our ELISA detection limit.

SYNTHESIS OF INTERFERON-α_A MONOCLONAL ANTIBODY PACKING MATERIAL IN HIGH-PERFORMANCE AFFINITY CHROMATOGRAPHY AND PURIFICATION OF RECOMBINANT HUMAN INTERFERON-α_A

A new way for the synthesis of human interferon—α;monoclonal antibody （IFN-α;-McAb） bound to silica gel packing material in high-performance affinity chromatography （HPAFC） has been developed. The high coupling efficiency and specific activity of IFN—α;-McAb can be obtained by activated diol-silica gel with activating agent. After purification using this packing material in HPAFC, the specific activity of recombinant human interferon-α;（rIFN-α;） rose up to 1.03×10;IU/mg protein and the purification efficiency is appoximately 100 times.

THE USE OF ANTI-HUMAN GLIOMA MONOCLONAL ANTIBODIES FOR TARGETING CHEMOTHERAPY OF BRAIN GLIOMAS(PREPARATION AND CYTOTOXIC PROPERTIES OF ANTIBODY-ADRIAMYCIN IMMUNOCONJUGATES)

Immunoconjugates are antibody-drug hybrid molecules which combine the exquisite selectivity or monoclonal antibodies with the potent toxicity of anticancer agents. A monoclonal antibody SZ39 against human brain gliomas was used as a drug carrier. Adriamycin (ADR) was bound covalently to SZ39 to form a SZ39-ADR conjugate. The cytotoxic activity of the SZ39-ADR conjugate was tested in vitro and demonstrated potent and specific killing of cells derived from a human malignant glioma. 50% inhibitory concentration (IC50) for SZ39-ADR to 'target' cells was 8.14×10-9 M. An index of specificity between 'target' and 'non-target' cells was calculated to be 88-fold. These data suggest that the SZ39-ADR may use as a potent and cell type-specific agent and is a likely candidate for the targeting chemotherapy of malignant gliotnas.

Studies on Purification of Methamidophos Monoclonal Antibodies and Comparative Immunoactivity of Purified Antibodies

To purify Methamidophos (Met) monoclonal antibodies with two methods and compare immune activity of purified antibodies. Method Caprylic acid ammonium sulphate precipition (CAASP) method and Sepharose protein-A (SPA) affinity chromatography method were used to purify Met monoclonal antibodies, UV spectrum scanning was used to determine protein content and recovery of purified antibodies, sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze the purity of purified antibodies, and enzyme-linked immunosorbent assay (ELISA) was used to determine immune activity of purified antibodies. Results Antibody protein content and recovery rate with CAASP method were 7.62 mg/mL and 8.05% respectively, antibody protein content and recovery rate with SPA method were 6.45 mg/mL and 5.52% respectively. Purity of antibodies purified by SPA method was higher than that by CAASP method. The half-maximal inhibition concentration (IC50) of antibodies purified by SPA to Met was 181.26 靏/mL, and the linear working range and the limit of quantification (LOD) were 2.43-3896.01 靏/mL and 1.03 靏/mL, respectively. The IC50 of antibodies purified by CAASP to Met was 352.82 靏/mL, and the linear working range and LOD were 10.91-11412.29 靏/mL and 3.42 靏/mL, respectively. Conclusion Antibodies purified by SPA method are better than those by CAASP method, and Met monoclonal antibodies purified by SPA method can be used to prepare gold-labelled testing paper for analyzing Met residue in vegetable and drink water.

PURIFICATION OF MONOCLONAL ANTIBODY 3HII AGAINSTGASTRIC CANCER FOR IN VIVO USE

Monoclonal antibody (McAb) 3Hll against gastriccancer was grown in the mouse ascites system. Toacquire a clinical grade product for cancer radioimmuno-imaging was purified by two step highperformance liquid chromatography (HPLC) protocolusing protein A and high-performance hydroxylapatite(HPHT). An analysis of data reported shows the twostep HPLC method to be the best purificationprocedure. This protocol satisfies purity and immunoreactivity requirement, and provides an sample sterility,free-pyrogens, free-mycoplasma and non-specific IgGcontamination. This procedure described was capable ofgenerating large amounts of clinical grade monoclonalantibody.

Expression and purification of Ctomp2aa167-aa434 and preparation of its mAb

Chlamydia trachomatis outer membrane protein 2 (Ctomp2) is a major immunogen in chlamydial infections and a highly genus-conserved structural protein of all Chlamydia species . To purify the protein and to prepare monoclonal antibodies (mAbs) against it, the recombinant protein was induced by IPTG, which was confirmed by SDS-PAGE and purified by means of a Ni2+ -charged resin column. The denatured protein was refolded in the GSH-GSSH buffer gradually and identified by Western blotting. Then the BALB/c mice were immunized with the recombinant protein to prepare the mAb against Ctomp2. The obtained mAbs were characterized. Genital specimens were tested with indirect ELISA mostly made of the mAb and cell culture in 84 patients with genital symptoms. The results showed that high-level expression of the recombinant protein was achieved, which existed as inclusion body and amounted to 38 % of total bacterium protein. A mAb against Ctomp2 was obtained. It belongs to IgG 2b. The titers were as high as 1:40 000. The Western blotting showed that the mAb only reacted with the recombinant protein. It had no crossing reactions against E. coli, N. gonorhoea, M. hominis, U. urealyticum and M. penetrans . It had high specifity. In comparison with gold standard test-cell culture, the sensitivities, specificities, positive predictive values and negative predictive values of indirect ELISA were 95.24%, 100%, 100% and 98.44%, respectively. The above-mentioned research work contributed not only to the further study of the structure and function of this protein , but also to the establishment of the method for its clinical application, for it had not been reported before.

Recombinant Expression of a Novel Human Transcriptional Repressor HMBOX1 and Preparation of Anti-HMBOX1 Monoclonal Antibody

HMBOX1 was a novel transcription factor possibly involving in function of pancreas and cytotoxicity of NK cells. For function determination, recombinant human HMBOX1 protein was obtained and purified, and the monoclonal antibodies against HMBOX1 were prepared. The full-length cDNA fragment encoding HMBOX1 was amplified from NK-92 cells and inserted into prokaryotic expression vector pET22b. The pET22b-HMBOX1-6his vector was then transformed into E. coli Rosetta （DE3） and induced by 1 mM IPTG for 4 h at 37℃. The fusion HMBOX1 protein was mainly expressed in inclusion bodies, which was purified and refolded using Ni^2＋-affinity chromatography. With the purified fusion HMBOX1 protein as antigen, monoclonal antibodies against HMBOX1 were generated, providing a potentially useful tool for further study in HMBOX1 functions. Using these anti-HMBOX1 mAbs, we identified that HMBOX1 is located in both cytoplasm and nucleus and could be detected in 10 human normal tissues, including cerebrum, pancreas, kidney and liver tissues. Moreover, the expression in hepatic carcinoma was significantly lower than that in adjacent tissues.

Preparation and characterization of monoclonal antibody against recombinant human tissue factor pathway inhibitor

Objective To prepare and identify monoclonal antibody (McAb) against recombinant human tissue factor pathway inhibitor (rhTFPI) and to use it for measurement of TFPI by ELISA, and to evaluate the effects of the McAb on dilute prothrombin time (PT) and activated partial thromboplastin time (APTT).Methods After intrasplenic immunization of Balb/c mouse with TFPI, hybridoma technique was used to raise monoclonal antibody against rhTFPI. The McAb was wellcharacterized and labelled with horseradish peroxidase (HRP) by using assay of TFPI in ELISA. Furthermore, the McAb was added to normal and factor Ⅸ deficient plasma for observation of dilute PT and APTT.Results Two hybridomas (4F4, 4F8) secreting McAb against TFPI were established. The Ig class and subclass of the McAb purified from 4F8 was IgG1. Immunoblotting results indicated that the McAb4F8 only recognized a single band of TFPI with molecular weight of 34.8 KD. The results of Sandwich enzymelinked immunosorbent assay (ELISA) by using the HRP labelled McAb4F8 showed that the mean of TFPI in normal human plasma is 103.2±11.5 μg/L. The McAb 4F8 was also proved to shorten markedly dilute prothrombin time of factor Ⅸ deficient plasma and normal plasma.Conclusions We established two hybridomas cell lines (4F4, 4F8) and obtained the McAb4F8 against TFPI and reported the levels of TFPI in healthy adult human plasma by Sandwich ELISA with HRP labelled McAb4F8 in Chinese.

TREM2单克隆抗体的制备及应用检测

目的:制备TREM2特异性单克隆抗体并对其特异性、亲和力及在免疫学检测中的应用进行鉴定,为TREM2的抗体药物研发奠定基础。方法:表达并纯化TREM2胞外段GST融合蛋白,用其作为抗原免疫小鼠,筛选抗血清效价较高的小鼠,经过细胞融合和单克隆筛选,制备TREM2的特异性单克隆抗体。对获得的单克隆抗体的特异性、亲和力及其在免疫学实验中的应用进行检测。结果:获得了29株TREM2单克隆抗体,其中的24株可与TREM2特异性结合;29株单抗与TREM2结合的EC50均在nmol以上;它们可分别在Western blot、免疫沉淀、流式细胞术和免疫荧光中用于对TREM2的特异检测。结论:成功制备并获得了亲和力高、特异性好的抗TREM2单克隆抗体,为TREM2靶点的成药性抗体开发奠定了基础。

小鼠抗NLRP3单克隆抗体的制备及鉴定

目的 制备小鼠抗含pyrin结构域核苷酸结合寡聚结构域样受体家族蛋白3(NLRP3)的单克隆抗体(mAb)并检测其特异性。方法 将编码小鼠NLRP3基因外显子3(Ms-N3)的基因片段插入载体p36-G3-throhFc中构建重组质粒Ms-N3-throhFc,然后将该质粒转染到HEK293F细胞中,进行真核蛋白表达。进一步利用蛋白A亲和层析柱纯化得到Ms-N3蛋白并免疫NLRP3基因敲除(NLRP3^(-/-))小鼠,将免疫小鼠的脾细胞与SP2/0骨髓瘤细胞融合形成杂交瘤细胞。进而通过ELISA和免疫荧光方法筛选能够分泌特异性识别小鼠NLRP3的mAb的杂交瘤细胞。结果 成功构建Ms-N3-throhFc重组质粒并证明该质粒能在HEK293F细胞中稳定表达。ELISA初步筛选获得12株杂交瘤细胞,经过免疫荧光实验检测发现其中的9-B8-3-2-C5分泌的mAb能够特异性识别非变性的小鼠NLRP3蛋白,该mAb的重链亚型为IgM,轻链亚型为κ。结论 成功获得小鼠抗NLRP3 mAb。

人5-脂氧合酶重组蛋白的纯化及其多克隆抗体的制备

目的:原核表达并纯化人5-脂氧合酶(5LO)△112蛋白,将其免疫新西兰大白兔制备5-LO多克隆抗体。方法:使用DNAMAN设计重组引物,PCR扩增N端缺失112个氨基酸的5-LO截短DNA片段,将其重组到KpnⅠ和EcoRⅠ酶切的pET30a(+)质粒中,重组质粒pET30a-5LO△112转化大肠杆菌Rosetta(DE3),培养至OD_(600)为0.4时加入IPTG以诱导5LO△112重组蛋白表达,目的蛋白经纯化后免疫新西兰大白兔制备其多克隆抗体。结果:使用BugBuster蛋白提取试剂裂解细菌并获得纯度较高的包涵体,包涵体用含6mol/L盐酸胍的溶液变性溶解,再经Ni-NTA agarose亲和纯化得到高纯度的5LO△112重组蛋白。用该蛋白免疫新西兰大白兔获得5-LO的特异性抗体,该抗体的效价为1∶51200。结论:使用6mol/L盐酸胍溶解包涵体蛋白结合Ni-NTA agarose亲和纯化的方法成功获得了纯度较高的5LO△112重组蛋白,并用此蛋白制备了高效价的多克隆抗体。

Mycoplasma infections and different human carcinomas

AIM To explore relationships between human carcinomas and mycoplasma infection.METHODS Monoclonal antibody PD4, which specifically recognizes a distinct protein from mycoplasma hyorhinis, was used to detect mycoplasma infection in different paraffinembedded carcinoma tissues with immunohistochemistry. PCR was applied to amplify the mycoplasma DNA from the positive samples for confirming immunohistochemistry.RESULTS Fifty of 90 cases (56%) of gastric carcinoma were positive for mycoplasma hyorhinis. In other gastric diseases, the mycoplasma infection ratio was 28% (18/49) in chronic superficial gastritis, 30% (14/ 46) in gastric ulcer and 37% (18/ 49) in intestinal metaplasia. The difference is significant with gastric cancer (X2=12.06, P＜0.05). In colon carcinoma, the mycoplasma infection ratio was 55.1% (32/58), but it was 20.9% (10/49) in adenomarous polyp (X2=13.46, P＜0.005).Gastric and colon cancers with high differentiation had a higher mycoplasma infection ratio than those with low differentiation (P＜ 0.05). Mycoplasma infection in esophageal cancer, lung cancer, breast cancer and glioma was 50.9% (27/53), 52.6% (31/ 59), 39.7%(25/63) and 41% (38/91), respectively. The mycoplasma DNA was successfully amplified with the DNA extracted from the cancer tissues that were positive for mycoplasma infection (detected with antibody PD4).CONCLUSION There was high correlation between mycoplasma infection and different cancers, which suggests the possibility of an association between the two. The mechanism involved in oncogenesis by mycoplasma remains unknown.

禽流感病毒NP蛋白单克隆抗体的制备与鉴定

为获得禽流感病毒(Avian influenza virus,AIV)NP蛋白的单克隆抗体,将构建的重组表达质粒pET-30a-NP转化BL21细胞,经IPTG诱导表达、纯化后作为免疫原,免疫8周龄Balb/c雌性小鼠,并按常规方法制备杂交瘤细胞。通过ELISA方法、Western-blot方法进行筛选,获得3株杂交瘤细胞株,命名为3A6、2H12、5F7,并进行了培养特性、分泌抗体活性、分泌抗体亚类的鉴定。结果显示:3株细胞株连续传10代均稳定分泌单克隆抗体,分泌的单克隆抗体亚型均为IgG2b,轻链类型均为Kappa。制备并纯化了以上3株单克隆抗体,浓度分别为2.9、2.5、2.8 mg/mL,纯度不低于90%。West-blot检测,单抗与H7血凝抑制试验抗原、H5血凝抑制试验抗原、H9N2病毒能发生特异性反应,说明单抗具有广谱性,且与IBDV、REV、IBV、MDV、ALV、AE、ILT、NDV、EDSV等均无特异性条带出现,说明特异性良好。本研究制备的3株针对禽流感NP蛋白的单抗,具有较好的特异性、保守性和广谱性,为下一步开展AIV诊断试剂如IFA检测试剂盒、ELISA检测试剂盒等的研制奠定了物质基础。

识别α-synuclein N端结构域的单克隆抗体鉴定及免疫应用

目的分析5种识别α-突触核蛋白(α-synuclein,α-syn)N端结构域的单克隆抗体1C16、2B8、2P21、3O18和1J6的特异性,为帕金森病(Parkinson s disease,PD)的早期诊断和免疫治疗提供抗体支持。方法体外蛋白重组技术获得人源α-syn蛋白(human-α-syn,h-α-syn)、鼠源α-syn蛋白(mouse-α-syn,m-α-syn)、β-syn蛋白、N端人源α-syn蛋白(α-syn/N)和去N端人源α-syn蛋白(α-syn/ΔN)。斑点印迹法鉴定5种单克隆抗体的特异性识别结构域,使用蛋白质印迹技术检测其对变性后的纯蛋白和鼠脑组织的识别情况。结果抗体1C16可以识别非变性的h-α-syn纯蛋白和小鼠脑组织中的变性的h-α-syn蛋白,不识别m-α-syn和β-syn。抗体1J6仅识别非变性的h-α-syn及α-syn/N纯蛋白,不识别变性后的全长α-syn纯蛋白和小鼠脑组织中的变性h-α-syn蛋白。结论筛选出的2种单克隆抗体具有特异性,可为本实验下一步生物标志物的酶联免疫吸附法测定检测和针对α-syn的免疫治疗提供基础。

养殖鲫鲤疱疹病毒2型的鉴定及病毒囊膜蛋白ORF131多抗的制备

为了解鲤疱疹病毒2型(cyprinid herpesvirus 2,CyHV-2)在南京地区养殖场鲫鱼中的发病情况,对南京某渔场疑似CyHV-2感染鱼,采集鳃、肾脏等组织进行解旋酶基因(hel)PCR扩增测序及遗传变异分析;通过蔗糖密度梯度离心从发病鲫鱼组织中提纯病毒粒子,电镜观察其形态;对CyHV-2的10种囊膜蛋白编码基因进行测序,并基于生物信息学分析选择理想的囊膜蛋白进行原核表达,免疫小鼠制备抗血清。结果显示:患鱼组织hel基因检测阳性,其序列与参考株ST-J1毒株hel基因序列(GenBank登录号:JQ85364)高度同源(99.67%),并位于同一进化分支;利用蔗糖密度梯度离心结合Western blot检测发现,病毒粒子存在于40%~46%蔗糖层,电镜观察显示直径在160 nm左右;10种囊膜蛋白中开放阅读框131(ORF131)囊膜蛋白具有一段连续B细胞表位且抗原性良好,将ORF131原核表达、免疫小鼠后制备的抗血清ELISA效价达1∶4000。本研究为南京地区CyHV-2感染的检测和防控提供了依据。

莱克多巴胺单克隆抗体非亲和层析法纯化研究

抗体纯化对免疫测定和生物偶联的灵敏度、重现性和稳定性具有重要影响。本文对硫酸铵沉淀法(Ammonium sulfate precipitation,AS)及AS分别与阴离子交换层析法(Anion exchange chromatography,AEC)、阳离子交换层析法(Cation exchange chromatography,CEC)、疏水作用层析法(Hydrophobic interaction chromatography,HIC)和陶瓷羟基磷灰石法(Ceramic hydroxyapatite,CHT)联合应用纯化腹水来源的莱克多巴胺单克隆抗体(Ractopamine monoclonal antibody,RAC-mAb)进行了研究。优化缓冲液pH、盐浓度及层析介质,分别采用Bradford法、十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(Sodium dodecyl-sulfate polyacrylamide gel electrophoresis,SDS-PAGE)、间接竞争酶联免疫吸附试验(Indirect competitive enzyme-linked immunosorbent assay,icELISA)和胶体金免疫层析技术(Colloidal gold immunochromatography,CGIC)对抗体纯化后回收率、纯度及生物学活性进行评估。结果显示,采用AS+AEC法纯化抗体回收率高、纯度和生物学活性好,抗体回收率为40.1%,纯度为75.1%,经icELISA平行测定3次所得灵敏度(IC_(50))最佳为1.73±0.22 ng/mL,CGIC测定其在PBS及猪尿样本添加cut-off值分别为5 ng/mL和60 ng/mL。本研究为单克隆抗体纯化提供了理论参考和必要的实验基础。

东亚飞蝗DSCAM2多克隆抗体制备

制备唐氏综合征细胞粘附分子2(DSCAM2)多克隆抗体,拟为DSCAM2功能探索提供免疫学工具。采用生物信息学方法对DSCAM2抗原结构进行分析;利用DNA重组技术构建DSCAM2828-957重组表达菌株;采用Ni亲和层析技术纯化重组DSCAM2828-957蛋白,免疫小鼠制备Anti-DSCAM2多克隆抗体;采用ELISA法检测抗体效价、Western Blot法检测抗体特异性、瑞氏-吉姆萨染色和免疫荧光检测DSCAM2在东亚飞蝗血淋巴细胞定位;采用siRNA敲低DSCAM2,进行血淋巴细胞计数。结果表明,所构建的pET30a(+)-DSCAM2828-957/BL21(DE3)原核菌株成功表达重组DSCAM2828-957蛋白;用Ni螯合亲和层析分离获得的DSCAM2828-957重组抗原免疫小鼠,获得了效价高且特异性好的DSCAM2多克隆抗体;细胞定位分析显示DSCAM2在东亚飞蝗嗜碱性粒细胞高表达;敲低DSCAM2表达水平,引起东亚飞蝗总血淋巴细胞数量增多。

应用A蛋白亲和层析法纯化单克隆抗体

应用Protein A亲和层析法,从采集的小鼠腹水中纯化出了抗凝血因子Ⅶ单克隆抗体,用SDS-PAGE和ELISA法分别检测了纯化后单克隆抗体的纯度及效价,结果显示,电泳为两条带,分别为免疫球蛋白G(IgG)的重链和轻链,纯化后的单克隆抗体纯度达到电泳纯,应用间接ELISA法测定腹水效价为1×10-7左右,与未纯化前无差异。结果表明,应用A蛋白亲和层析法能够得到纯度较高的单克隆抗体,适用于高纯度单克隆抗体的制备。

抗河豚毒素单克隆抗体的制备及其特性的初步研究

将用合成的匙孔形虫戚血蓝蛋白－甲醛－河豚毒素（ＫＬＨ－ＨＣＨＯ－ＴＴＸ）连接物免疫的ＢＡＬＢ／ｃ小鼠的脾细胞与小鼠骨髓瘤细胞系Ｓｐ２／０融合，经３～４次亚克隆，建立了３个稳定分泌抗河豚毒素的杂交瘤细胞株，分别命名为１Ｇ３、４Ｇ３、６Ｄ９。其中１Ｇ３和４Ｇ３分属ＩｇＧ２ｂ亚类，６Ｄ９属ＩｇＧ１亚类。腹水的抗体稀释度为１∶１０５～１：５×１０６。用竞争抑制性酶联免疫吸附试验（ＥＬＩＳＡ）测定三种抗体的最低反应浓度为１×１０－３ｍｇ／Ｌ。

大鼠脑红蛋白(NGB)可溶性原核表达和单克隆抗体制备及鉴定

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