检测抗HIV-1/2型抗体的双抗原夹心方法的建立及其试剂盒的研制

目的 建立更敏感的检测人免疫缺陷病毒（HIV）抗体的方法,并研制检测试剂盒。方法 根据HIV－1／2型的基因序列及其所编码氨基酸结构,采用固相法合成了HIV－1型的gp41.1、gp41.2、gp120、p24和HIV－2型的gp36五条多肽,混合包被酶标板作为固相抗原。用辣根过氧化物酶标记以上多肽抗原作为标记物,建立检测血清中抗HIV－1／2抗体的双抗原夹心ELISA法。同时,应用该方法制备检测HIV抗体的试剂盒,并检测三批中国卫生中药品和生物制品检定所HIV诊断试剂国家参比品。结果 建立了检测HIV－1／2抗体的双抗原夹心法。用检定所参比品检测,该方法特异性、灵敏度均为100％,变异系数小于10％。与间接法相比较其灵敏度、特异性均高于间接法（P＜0．05）。检测210份其他病种患者血清均为阴性。与GBI公司的HIV抗体诊断试剂比较,检测40份卫生部药品和生物制品检定所提供的质控参比品（阳性20份,阴性20份）,GBI试剂阴、阳性符合率及总符合率分别为100%(20/20)、85％（17／20）及92．5％（37／40）,而应用该方法所研制的诊断试剂盒、阳性符合率及总符合率为100％。该试剂已通过国家卫生部质检。与雅培公司HIV诊断试剂比较检测90份献血员血清和88份HIV－1／2型感染者血清,符合率为100％。试剂盒于37℃放置4d后的检测结果的阴、阳性判定不受影响。结论 本法特异性强、灵敏度高、稳定性好,适用于献血员的筛选和临床HIV感染的检测。     

抗HIV-1 gp120单克隆抗体的制备及其初步应用

目的：制备抗HIV-1 gp120单克隆抗体（mAb），并建立一种可用于检测gp120的ELISA法。方法：采用基因工程抗原HIV-1gp120免疫BALB／c小鼠，通过B细胞杂交瘤技术制备抗HIV-1gp120的mAb。用ELISA法答定mAb的Ig亚类、效价及特异性。用饱和硫酸铵（SAS）纯化mAb，并用HRP标记后建立双mAb夹心ELISA法。结果：筛选出10株稳定分泌抗HIV-1gp120 mAb的杂交瘤细胞株，9株为IgG，其中4株的腹水效价为32X10～256X10所得mAb与HIV-1gp41、HIV-1p24及HIV一2gp36Ag均无交义反应，仅与HIV-1gp120产生特异性反应。用mAb 6H9和9H12，建立了双夹心ELISA法，检测gp120抗原的灵敏度是10μg／L。结论：获得10株特异性强、效价高的机HIV-1gp120的mAb，并建立了灵敏度良好的双mAb夹心ELISA法.     

多种单抗联合检测HIV抗原

目的 建立多种单抗联合早期检测HIV抗原的夹心ELISA方法.方法 以SAS盐析沉淀法和亲和层析法纯化抗HIV-1 p24、gp41、gp120及抗HIV-2 gp36的腹水型单克隆抗体(McAb),用高碘酸钠法将纯化的McAb以HRP进行标记.建立针对单个抗原的双抗体夹心ELISA法,对其灵敏度及特异性进行检测.将筛选得到的4株捕获McAb按比例混合作为捕获抗体,4株酶标McAb按比例混合作为检测抗体,建立多种单抗联合检测HIV抗原的夹心ELISA方法,检测混合HIV抗原.结果 按确定的最优反应条件建立的多种McAb联合夹心ELISA方法,检测到的最高稀释度的HIV混合抗原中各抗原的终浓度分别为:重组HIV-1 p24:0.625 pg/ml,gp41:6.25 ng/ml,gp120:6.25 ng/ml;HIV-2 gp36:9.25 ng/ml.结论 建立了具有高度敏感性的鸡尾酒式多种单抗联合检测HIV抗原的夹心ELISA法,为早期榆测HIV抗原提供了新的思路,为后续的研究奠定了一定基础.     

多种单抗联合检测HIV抗原

目的 建立多种单抗联合早期检测HIV抗原的夹心ELISA方法.方法 以SAS盐析沉淀法和亲和层析法纯化抗HIV-1 p24、gp41、gp120及抗HIV-2 gp36的腹水型单克隆抗体(McAb),用高碘酸钠法将纯化的McAb以HRP进行标记.建立针对单个抗原的双抗体夹心ELISA法,对其灵敏度及特异性进行检测.将筛选得到的4株捕获McAb按比例混合作为捕获抗体,4株酶标McAb按比例混合作为检测抗体,建立多种单抗联合检测HIV抗原的夹心ELISA方法,检测混合HIV抗原.结果 按确定的最优反应条件建立的多种McAb联合夹心ELISA方法,检测到的最高稀释度的HIV混合抗原中各抗原的终浓度分别为:重组HIV-1 p24:0.625 pg/ml,gp41:6.25 ng/ml,gp120:6.25 ng/ml;HIV-2 gp36:9.25 ng/ml.结论 建立了具有高度敏感性的鸡尾酒式多种单抗联合检测HIV抗原的夹心ELISA法,为早期榆测HIV抗原提供了新的思路,为后续的研究奠定了一定基础.     

HIV-1 膜蛋白基因片段杆状病毒转移载体克隆及重组体的构建

目的：构建编码HIV－1外膜糖蛋白的gp120和gp41基因杆状病毒转移载体，并在昆虫细胞中表达gp120和gp41重组蛋白。方法：从HIV－1基因克隆PNL4－3（NY5／LAV）中应用聚合链反应扩增目的基因gp120和gp41，克隆到PGEM－T载体中，限制性内切酶酶切、DNA序列分析鉴定目的基因，再经EcoRI和BamHI双酶切后定向克隆到杆状病毒转移载体PAC－SecG2T中，再次测序鉴定。通过在sf9昆虫细胞中同源重组、空斑筛选、病毒鉴定、SDS－PAGE、Western-blot对重组病毒和重组蛋白进行分析。结果：限制性内切酶酶切和DNA序列分析表明，gp120和gp41正确克隆到杆状病毒转移载体PACSecG2T中；SDS－PAGE和Eestern-blot结果表明在昆虫细胞中成功表达了HIV外膜糖蛋白gp120和gp41。结论：成功构建了PACSecG2T-gp120和PACSecG25-gp41杆状病毒转移载体，并在杆状病毒－昆虫细胞表达系统中表达了HIV－1 gp120和gp41重组蛋白，Western-blot证明具有较好的免疫原性。     

HIV抗体纳米免疫磁珠快速检测试剂的研制

目的 研制一种用纳米免疫磁珠层析技术用以检测HIV抗体的快速诊断试剂.方法 运用碳二亚（EDC）将重组的HIV抗原gp41、gp36偶联到200 nm的超顺磁纳米颗粒上,在硝酸纤维素（NC）膜上包被gp41、gp36抗原,制备成免疫层析检测卡,然后对检测卡进行性能分析评估.结果 对HIV抗体国家参考品血清盘（胶体金类）检测,符合要求;对20份HIV抗体阳性和600份抗体阴性临床血清检测,灵敏度为100%,特异性为98.5%.检测卡室温保存12个月性能稳定.结论 研制出一种纳米免疫磁珠HIV抗体检测试剂,具有检测简便、快速、稳定性好和适于现场检测等特点.     

HIV抗体纳米免疫磁珠快速检测试剂的研制

目的 研制一种用纳米免疫磁珠层析技术用以检测HIV抗体的快速诊断试剂.方法 运用碳二亚(EDC)将重组的HIV抗原gp41、gp36偶联到200 nm的超顺磁纳米颗粒上,在硝酸纤维素(NC)膜上包被gp41、gp36抗原,制备成免疫层析检测卡,然后对检测卡进行性能分析评估.结果 对HIV抗体国家参考品血清盘(胶体金类)检测,符合要求;对20份HIV抗体阳性和600份抗体阴性临床血清检测,灵敏度为100%,特异性为98.5%.检测卡室温保存12个月性能稳定.结论 研制出一种纳米免疫磁珠HIV抗体检测试剂,具有检测简便、快速、稳定性好和适于现场检测等特点.     

HIV抗体纳米免疫磁珠快速检测试剂的研制

目的 研制一种用纳米免疫磁珠层析技术用以检测HIV抗体的快速诊断试剂.方法 运用碳二亚(EDC)将重组的HIV抗原gp41、gp36偶联到200 nm的超顺磁纳米颗粒上,在硝酸纤维素(NC)膜上包被gp41、gp36抗原,制备成免疫层析检测卡,然后对检测卡进行性能分析评估.结果 对HIV抗体国家参考品血清盘(胶体金类)检测,符合要求;对20份HIV抗体阳性和600份抗体阴性临床血清检测,灵敏度为100%,特异性为98.5%.检测卡室温保存12个月性能稳定.结论 研制出一种纳米免疫磁珠HIV抗体检测试剂,具有检测简便、快速、稳定性好和适于现场检测等特点.     

HIV-1 gp41重组抗原的表达及其免疫反应性检测

为了在大肠杆菌中表达具有良好免疫反应性的HIV-1gp41重组抗原,本实验运用基因工程技术,经PCR扩增gp41的主要抗原表位序列,BamHⅠ、XhoⅠ双酶切后与E3质粒连接,转化克隆宿主菌DH5α,再提取重组质粒进一步转化表达宿主菌BL21(DE3),经IPTG诱导表达重组蛋白,纯化后标记HRP,通过双抗原夹心酶联免疫方法检测其免疫反应性和特异性。结果表明,获得的HIV-1gp41重组抗原能够与相应抗体特异性结合,与多种无关抗体间无交叉反应,对825份HIV阴性标本检测无错检。检测结果说明该重组抗原具有良好的免疫反应性,在HIV-1抗体诊断试剂中具有潜在的应用价值,为进一步研究gp41抗原奠定了基础。     

双抗原夹心法检测抗HIV-1/2总抗体方法的建立和评价

目的 进一步提高HIv感染诊断试剂的敏感性。方法 以人工合成的HIv—1 gp41．1(sP1)、gp41．2(sP2)、gp120(sP3)、P24(sP4)和HIV—2gp36(sP5)5条多肽，采用双抗原夹心酶链免疫吸附试验(ELISA)原理，以sP1、sP3、sP4和sP5混合包被酶标板作为因相抗原，辣根过氧化物酶标记sp1、sp2、sP4和sP5多肽为标记物，建立了检测抗HIV—1／2总抗体的双抗原夹心ELISA法。结果 检测卫生部药品生物制品检定所第2代40份质控参比血清，其特异性和灵敏度均为100％，高于间接ELISA法(特异性为90％，灵敏度为65％)。检测210份其他病种患者血清均为阴性，与雅培HIVAB试剂比较检测如份健康献血员血清和88份HIv感染者血清，符合率为100％。结论 本方法特异性强、敏感性高，操作简便，适用于献血员的筛选和临床HIv感染的检测。     

HIV 外膜糖蛋白 gp120 和 gp41 在昆虫细胞中表达及其免疫学特性的评价

将编码完整ｇｐ１２０和完整ｇｐ４１的基因分别克隆到杆状病毒转移质粒中。使用重组转移质粒与野生杆状病毒（ＡｃＮＰＶ）ＤＮＡ共转染Ｓｆ９昆虫细胞，经挑选获得分别带有编码ｇｐ１２０和ｇｐ４１基因的重组杆状病毒。重组杆状病毒感染Ｓｆ９细胞后在细胞中分别表达了ＨＩＶ外膜糖蛋白ｇｐ１２０和ｇｐ４１。其重组蛋白的分子量分别为１２０×１０３和４１×１０３。此重组糖蛋白在免疫荧光、免疫印染和酶联免疫实验中都能被ＨＩＶ阳性血清所识别。动物免疫实验表明此重组糖蛋白能诱导很强的特异性抗体产生。     

用细菌／杆状病毒系统在昆虫细胞中表达HIV—2外膜糖蛋白gp105和跨膜糖蛋白g

目的 用细菌／杆状病毒（Ｂａｃ ｔｏ Ｂａｃ）表达系统在昆虫细胞Ｓｆ９中表达ＨＩＶ－２外膜糖蛋白ｇｐ１０５跨膜糖蛋白ｇｐ３６,为研制艾滋病疫苗和诊断试剂奠定基础。方法 分别将ＨＩＶ－２外膜蛋白ｇｐ１０５和跨膜蛋白ｇｐ３６全基因序列克隆到杆状病毒转座载体ｐＦａｓｔ Ｂａｃ ＴＨａ和ｐＦａｓｔ Ｂａｃ ＴＨｂ中我角体启动子下游,构建成重组转座载体ｐＦａｓｔ Ｂａｃ ＨＴａ－ｐｇ１０５和ｐＦａｓｔ Ｂａｃ ＨＴｂ－ｇｐ３６,利用细菌／杆状病毒（Ｂａｃ ｔｏ Ｂａｃ）表达系统筛选重组杆状病毒,并在昆虫细胞Ｓｆ９中表达ＨＩＶ－２的ｇｐ１０５和ｇｐ３６。结果 ＳＤＳ－ＰＡＧＥ分析结果表明,ｐｇ１０５基因表达产物为－６６０００ｕ糖蛋白,ｐｇ３６基因则表达－４１０００ｕ糖蛋白,与天然产物一致。Ｗｅｓｔｅｒｎ ｂｌｏｔ结果显示：     

Free and antibody-complexed antigen and antibody profile in apparently healthy HIV seropositive individuals and in AIDS patients

The pattern of free and antibody-complexed HIV antigen and the antibody profile were investigated retrospectively in 305 serum samples taken from 22 AIDS patients before and during the development of AIDS and from 40 apparently healthy seropositive individuals. Most AIDS patients were found positive for both free and complexed antigen and had high gp41 antibody titres but low or undetectable p24 antibody. Four different patterns of HIV antigenaemia were observed: 1) positive for both free and complexed antigen; 2) negative for free HIV antigen at first, but always positive for complexed antigen; 3) positive for free antigen without complexed antigen; and 4) negative for both free and complexed antigen. The development of immune complexes preceded the appearance of free antigen and might reflect the ongoing viral replication with antigen excess and binding of anticore antibodies. No correlation was found between the development of AIDS symptoms and either the duration of free antigen positivity or the level of antigenaemia. A different pattern was observed in apparently healthy seropositive individuals: 90% of whom had high antibody titres to p24 and gp41 and were persistently negative for free and complexed HIV antigen. This study demonstrates that testing HIV markers in sequentially collected serum samples from HIV seropositive individuals is a useful and simple tool for early identification of persons at risk of developing AIDS.     

抗HIV p24和人A型红细胞双特异性单克隆抗体的研制

目的：制备抗HIV p24和人A型红细胞双特异性单抗(mAb)，并建立检测HIV p24的间接血凝试验。方法：将分泌抗HIV p2d mAb的杂交瘤株2-E4和分泌抗人A型红细胞mAb的杂交瘤株S2，分别用8-Ag和5-BrdU驯化，使成为HAT敏感株。将两者常规融合，筛选分泌双特异性mAb的杂交-杂交瘤株。然后制备并纯化双特异性mAb，用其建立的间接血凝法检测p24。结果：共获得6株杂交-杂交瘤细胞株，以其分泌的双特异性mAb建立了检测HIV p24的间接血凝法，敏感性可达400ng/L。结论：获得可稳定分泌双特异性mAb的杂交-杂交瘤株，并用纯化的双特异性mAb建立了快速检测HIV p24的间接血凝法。     

Sensitivity of a rapid point of care assay for early HIV antibody detection is enhanced by its ability to detect HIV gp41 IgM antibodies

BackgroundAnti-HIV-1 IgM antibody is an important immunoassay target for early HIV antibody detection.ObjectivesThe objective of this study is to determine if the early HIV antibody sensitivity of the 60 s INSTI test is due to detection of anti-HIV-1 IgM in addition to IgG.Study DesignTo demonstrate HIV gp41 IgM antibody capture by the INSTI HIV-1 gp41 recombinant antigen, an HIV-IgM ELISA was conducted with commercial HIV-1 seroconversion samples. To demonstrate that the INSTI dye-labelled Protein A-based colour developer (CD) has affinity to human IgM, commercial preparations of purified human immunoglobulins (IgM, IgD, IgA, IgE, and IgG) were blotted onto nitrocellulose (NC) and probed with the CD to observe spot development. To determine that INSTI is able to detect anti-HIV-1 IgM antibody, early seroconversion samples, were tested for reduced INSTI test spot intensity following IgM removal.ResultsThe gp41-based HIV-IgM ELISA results for 6 early seroconversion samples that were INSTI positive determined that the assay signal was due to anti-HIV-1 IgM antibody capture by the immobilised gp41 antigen. The dye-labelled Protein-A used in the INSTI CD produced distinct spots for purified IgM, IgA, and IgG blotted on the NC membrane. Following IgM removal from 21HIV-1 positive seroconversion samples with known or undetermined anti-HIV-1 IgM levels that were western blot negative or indeterminate, all samples had significantly reduced INSTI test spot intensity.ConclusionsThe INSTI HIV-1/HIV-2 Antibody Test is shown to detect anti-HIV-1 IgM antibodies in early HIV infection which enhances its utility in early HIV diagnosis.     

Comparison of Western blot (immunoblot) based on recombinant-derived p41 with conventional tests for serodiagnosis of human immunodeficiency virus infections.

To evaluate the performance of a serological test for human immunodeficiency virus type 1 (HIV-1) infections based on the use of a recombinant envelope gene-derived protein as the antigen, we caused expression of a 1.4-kilobase fragment of HIV.DNA that codes for the complete gp41 transmembrane protein in an Escherichia coli expression vector and used Western blots (WB; immunoblots) prepared with recombinant material (pEX-41) to detect antibodies to HIV-1. This test detected all 339 sera which were positive by a combination of conventional serodiagnostic assays and produced no false-positive results with 311 negative samples. Also no false-positive results were obtained with 20 sera from systemic lupus erythematosus patients which had high titers of cross-reactive autoantibodies. In six cases, the pEX-41 WB proved to be more sensitive than individual assays applied on their own, and in five cases it was even more sensitive than a combination of conventional assays. We tested 221 sera in both our pEX-41 WB and a commercially available recombinant enzyme immunoassay (EIA [Abbott]). The results were identical in 188 cases. A total of 27 sera containing antibodies to gp41 as demonstrated in the pEX-41 WB, as well as the Abbott recombinant EIA, had no antibodies to the recombinant core antigen as measured in the Abbott EIA. However, 25 of these sera did stain the 24-kilodalton band on a WB with purified virus. Six sera that were positive in all of the conventional confirmatory assays and reacted strongly with the pEX-41 WB did not recognize the surface antigen used in the Abbott recombinant EIA. We conclude that the use of WB prepared with recombinant-derived p41 offers a very sensitive and specific method to detect antibodies to HIV.     

Evaluation of a simultaneous HIV antigen and antibody detection test in Korean population

Current diagnosis of human immunodeficiency virus (HIV) infection relies on the detection of anti-HIV antibodies by enzyme-linked immunosorbent assay (ELISA). Recently, kits detecting both p24 antigenemia and anti-HIV/anti-HIV2 antibodies have been developed. Thus, it is necessary to compare those kits developed as such. The aim of this study was to evaluate the diagnostic efficiency of a simultaneous detection test of p24 antigen and anti-HIV1/2 antibodies in a low prevalence area. Eight hundred and four randomly selected sera proven negative for HIV infection and 110 sera from 54 patients diagnosed as HIV infected, obtained between 1999 and 2000, were used for this study. One commercial lot of panels composed of consecutive sera obtained from known HIV-infected patient was included. Anti-HIV1/2 antibodies were detected by two different commercial ELISA kits, one from Korean and the other from German manufacturer. P24 antigen test was performed by ELISA. The simultaneous HIV antigen and antibody detection test was carried out. In the meantime, HIV RNA PCR and anti-HIV and anti-HIV2 western blot assays were also performed to confirm the test results in cases the test results didn't agree. The simultaneous detection kit showed 100% sensitivity and 99.6% specificity. Furthermore, the test displayed the possibility of earlier diagnosis than conventional anti-HIV1/2 ELISA with the results obtained from a group of consecutive panel sera infected with HIV. From these results, we concluded that the simultaneous HIV antigen and antibody detection test can be applied as a substitute clinical screening test in the place of conventional anti-HIV1/2 ELISA, and there is the probable benefit of early diagnosis.     

Flow cytometric assays for monitoring production of recombinant HIV-1 gp160 in insect cells infected with a baculovirus expression vector

A baculovirus expression system for the HIV-1 envelope glycoprotein gp160 has been used as a model for development of flow cytometric assays for monitoring production of cell-associated recombinant antigen. Using monoclonal antibodies to the transmembrane (gp41) or envelope (gp120) portion of gp160, gp120, but not gp41, could be reproducibly detected on the surface of insect cells 48 h after infection with the recombinant baculovirus. In contrast, fixation and permeabilization of infected cells prior to staining, to allow access of monoclonal reagents to the intracellular compartment, markedly improved the sensitivity of detection, with reactivity to both monoclonal antibodies observed at 24 h post-infection. Specificity of the intracellular immunofluorescence was verified by demonstrating that the appropriate native or recombinant HIV-1 protein blocked reactivity of monoclonal antibody with infected cells. In addition, it was observed that production of gp160 following baculovirus infection was associated with a marked increase in the 90 degrees light scatter of insect cells, as determined by flow cytometry, and that this correlated with the kinetics of cell-associated gp160 production as determined by immunofluorescence. These procedures should be of great utility for routine monitoring of recombinant proteins produced in insect cells in response to infection with recombinant baculovirus.     

Expression of gag precursor protein and secretion of virus-like gag particles of HIV-2 from recombinant baculovirus-infected insect cells

A recombinant baculovirus carrying the gag gene but lacking the protease coding sequences of human immunodeficiency virus type 2 (HIV-2) has been constructed. When this recombinant baculovirus is used to infect insect cells, a high level of gag precursor protein, gag pr41, is expressed. Electron microscopy showed that the majority of gag pr41 was budding through the plasma membrane and being released into the culture medium in spherical virus-like particles with a diameter of approximately 100 nm. Metabolic labeling demonstrates that gag pr41 is myristylated. Our results demonstrated that HIV-2 gag pr41 can be assembled into virus-like particles in the absence of other HIV proteins. Rabbits immunized with purified gag pr41 particles produced high-titer antibody and Western blot analysis showed that anti-gag pr41 rabbit sera recognize p17, p24, and p55 gag proteins of HIV-1. These results show that gag pr41 particles are highly immunogenic and that gag proteins of HIV-1 and HIV-2 have similar antigenic epitopes.