关于重组乙肝表面抗原纯化收率的研究

本文采用回归分析法研究了超速离心纯化时,固定一次溴化钾密度梯度比例,选择不同的二次溴化钾梯度比例对下一步ＳｅｐｈａｒｏｓｅＣＬ－４Ｂ柱层析纯化收率的影响。结果表明：回归分析不仅能揭示纯化的最佳条件,即,二次溴化钾超速离心时溶液由２４０ｍｌ（１．０４ｇ／ｍｌ）：８００ｍ１（１．２８ｇ／ｍｌ）：６００ｍｌ（１．３２ｇ／ｍｌ）：５０ｍｌ（１．３４ｇ／ｍｌ）构成时柱层析收率最高。而且还能解释层析纯化中出现的异常结果。     

重组CHO细胞乙肝表面抗原诱导小鼠细胞免疫应答的研究

为了研究重组CHO细胞乙肝表面抗原(CHO-rHBsAg)在小鼠中诱导T细胞免疫应答的能力,全面评价疫苗的免疫原性,以CHO-rHBsAg免疫BALB/c小鼠,常规制备小鼠脾脏淋巴细胞并在体外以抗原或特异多肽刺激;采用ELISA法测定抗原特异性T淋巴细胞分泌的细胞因子,乳酸脱氢酶法(LDH)测定抗原特异性细胞毒T淋巴细胞(CTL)活性,酶联斑点法(ELISPOT)测定CTL频数(CTLp),应用流式细胞仪分析T淋巴细胞亚群。结果显示,rHBsAg可在小鼠中诱导Th1及Th2类细胞因子;加铝佐剂的rHBsAg较未加佐剂的抗原可诱导较高水平的IFN-γ、CTL克隆及较高百分比的CD8+T淋巴细胞亚群。重组CHO细胞来源的HBsAg可在BALB/c小鼠中诱导一定程度的细胞免疫应答。     

基因乙肝表面抗原纯化工艺的初步改进

本文研究了新的层析介质（Ｃｅｌｌｕｆｉｎｅ）对原纯化工艺中ＳｅｐｈａｒｓｅＣＬ－４Ｂ柱层析纯化后的乙肝表面抗原（ＨＢｓＡｇ）组分及ＤＮＡ组分的进一步纯化效果。结果表明：该层析介质可以提高ＨＢｓＡｇ的纯度和收量,并对初步提纯ＤＮＡ组分中的乙肝表面抗原有一定意义。并首次发现ＤＮＡ组分中乙肝表面抗原的ＳＤＳ－ＰＡＧＢ图谱较正常基因乙肝表面抗原的图谱缺少３０ＫＤ的条带。     

疏水层析用于大规模纯化重组HBsAg的工艺研究

应用疏水层析法从CHO细胞培养液中纯化HBsAg,每根制备柱每次可处理细胞收液350L,在适宜的上样流速和层析温度条件下,层析后可去除96％的杂蛋白,再经超速离心和凝胶过滤层析,可获HBsAg纯品。经检定,HPLC纯度高于95％,其余各项检定指标均符合《中国生物制品规程》要求。结果表明,此方法纯化效率高、处理样品量大、成本低,适于大规模生产。     

纳米磁性颗粒标记的免疫层析法定量检测人乙型肝炎表面抗原

目的:应用纳米磁性颗粒标记的免疫层析法,研制可应用于乙肝表面抗原(HBsAg)快速定量检测的层析试纸条。方法:用1-乙基-3-(3-二甲基氨丙基)-碳化二亚胺(EDC)/N-羟基琥珀酰亚胺(NHS)交联的方法标记纳米磁珠,喷膜仪喷点硝酸纤维膜;根据双抗体夹心法原理建立免疫层析试纸条,对HBsAg特异性抗体捕获的磁信号进行检测,并对磁信号检测结果进行统计学分析和评价。结果:建立了HBsAg纳米磁性免疫层析试纸条,最低限度检测为0.1 ng/mL的HBsAg抗原,检测灵敏度达到了同类产品ELISA分析法的标准,且检测时间控制在5 min内;经检测临床血清标本证实,该方法可根据磁信号定量检测乙肝患者血清中HBsAg的浓度。结论:HBsAg纳米磁性免疫层析方法具有简单快速、灵敏度高的特点,可应用于临床血清样本中HBsAg的检测;该方法为体内极微量抗原抗体的快速检测建立了新模式。     

单克隆抗体亲合层析法快速提纯乙肝表面抗原

本文报道用乙型肝炎病毒单克隆抗体(抗-HBsMcAb)与活化琼脂糖(Minileak Low)结合制备亲合层析柱,用于提纯乙型肝炎病毒的表面抗原(HBsAg)。对纯化前后的表面抗原活性用RPHA法进行了检测,提纯后的效价比提纯前提高了20多倍。用免疫电镜(IEM)对提纯物观察可见满视野22nm的小圆颗粒。经SDS-PAGE电泳得出一条较清楚的带。对这项工作的意义进行讨论。     

聚乙二醇伴随式离子交换层析分离重组乙肝病毒表面抗原

对由中国仓鼠卵巢细胞(CHO)表达的多聚亚基蛋白HBsAg在离子交换层析过程中容易因亚基解离而导致蛋白解聚和丧失生物活性的难题,实验中选择聚乙二醇（PEG）作为保护剂伴随式（Polyethylene Glycol-Accompanied）离子交换层析分离纯化HBsAg。实验表明,在流动相中加入1% PEG10000(W/V)作为纯化伴侣, HBsAg的回收率由55% 左右提高到80%以上,纯化倍数基本保持在12左右。对纯化产物进行SDS_PAGE分析表明,1% PEG10000的纯化伴侣伴随式离子交换层析能全部保留HBsAg的糖基化蛋白单体（27kD和30kD）,高效液相色谱联用多角度激光散射(High Performance Size Exclusion Chromatography_Multiangle Laser Light Scattering, HPSEC-MALLS )进一步分析阐明了PEG能促使HBsAg颗粒尺寸分布更均一,结构更接近天然乙肝表面抗原。     

带有PreS的重组乙肝表面抗原在毕赤酵母中的表达

带有ＰｒｅＳ区的乙肝表面抗原（ＨＢｓＡｇ）有望成为新一代更高效的乙肝疫苗。利用毕赤属酵母（Ｐｉｃｈｉａ ｐａｓｔｏｒｉｓ）表达系统,表达了带有ＰｒｅＳ区免疫决定簇的理组乙肝表面抗原Ｓ１Ｓ、ＳＳ１和Ｓ２Ｓ。对表达产物的性质鉴定表明,产物可以形成２具有相应的Ｓ、ＰｒｅＳ１或ＰｒｅＳ２抗原性的颗粒,表达水平高于啤酒酵母（Ｓａｃｃｈａｒｏｍｙｃｅｓ ｃｅｒｅｖｉｓｉａｅ）表达系统。     

一种新型的琼脂糖疏水层析介质开发及其在重组乙肝表面抗原(CHO-HBsAg)分离纯化中的应用

以粒径均一的国产高交联度快速流琼脂糖为基质,采用活化、交联等步骤合成了针对分离纯化CHO-HBsAg的3C间臂的丁基琼脂糖疏水介质,通过控制丁基配基密度提高分离HBsAg的纯化倍数和回收率,获得了纯化倍数约20、HBsAg回收率约80%的介质。评估了合成介质的理化性质,流速为500cm/h时柱压力小于0.06MPa,表明介质具有较高的机械强度和良好的流动性能,介质经过酸、碱、变性剂等处理后化学性质稳定。将介质合成工艺进一步放大到2L介质/批,应用到HBsAg分离纯化的三步层析整和工艺中,结果表明,批量合成的疏水介质,HBsAg回收率与进口介质相当,HBsAg终产品纯度在95%以上,符合国家药典要求。最后考察了介质合成批次间的配基密度的可控性和单批次合成介质的重复使用性,结果表明,合成工艺和介质的重复性能满足产业化要求,这种成本低的介质有望替代目前工业生产广泛使用的进口疏水介质。     

Comparison of different elution conditions for the immunopurification of recombinant hepatitis B surface antigen

An immunoaffinity chromatographic method was developed using a mAb immunosorbent to purify recombinant hepatitis B surface antigen (r-HBsAg) from yeast. Elution conditions using a mAb-coated ELISA were improved to select the best conditions to purify r-HBsAg. The optimum results in terms of total quantitative recovery were obtained using 20 mM Tris pH 11.6. An increase in the CB.Hep-1 mAb (anti-HBsAg) useful immunosorbents half-life and in its yield per cycle was obtained when alkaline elution conditions were used. Moreover, the basic conditions do not affect either the antigenic characteristics or the purity or the molecular integrity of r-HBsAg.     

Fermentation of recombinant yeast producing hepatitis B surface antigen

Summary Fermentations were performed to determine parameters affecting the expression of hepatitis B surface antigen (HBsAg) in the yeastSaccharomyces cerevisiae containing the HBsAg gene. These studies emphasized inereasing both the relative abundance (HBsAg: cell mass) and total production of HBsAg. Specific activity was increased 70-fold when cells were grown in shake flasks containing nonselective rather than selective medium. The addition of adenine, ammonium sulfate or glucose to the complex medium reduced the production of antigen. Results similar to those achieved in shake flasks were obtained when the growth was performed in fermenters. A nutrient addition system was employed to increase the production of cells and HBsAg. The addition of glucose to the culture medium increased cell mass 6-fold but decreased the production of antigen. This imbalance was corrected by supplementing the glucose with complex nutrients.     

Size-exclusion chromatographic study of the reduction of recombinant hepatitis B surface antigen

The reduction of the P. pastoris-derived hepatitis B surface antigen (HBsAg) has been investigated by size exclusion chromatography performed in a detergent solution containing 0.3% sodium dodecyl sulfate (SDS) and 0.1 M Tris–HCl, pH 7.0. The HBsAg, reduced under different conditions and passed through the TSK G4000 SW column (600×7.5 mm I.D.) at 0.9 ml min⁻¹, was resolved into two peaks corresponding to the reduced, monomeric, and non-reduced forms, respectively. Under these conditions, the antigen fraction corresponding to the HBsAg dimer can be separated and completely reduced to monomers by repeated reductive treatment with simultaneous lipid removal. The efficiency of reduction was maximal after sample treatment with an equal volume of a solution containing 417 mM dithiothreitol, 4.2% (w/v) SDS and 16% (v/v) 2-mercaptoethanol. In conclusion, complete reduction of recombinant HBsAg to monomer subunits is possible and depends on the efficiency of lipid removal during the reductive treatment.     

Aggregation of recombinant hepatitis B surface antigen in Pichia pastoris

The combination of immunoaffinity and size-exclusion chromatography (SEC) is a powerful tool to analyze multiprotein particle assembly. This approach was used to investigate the source of aggregation of recombinant hepatitis B surface antigen (HBsAg) detected in purified material. As HBsAg aggregation does not originate in the stresses, such as the concentration of HBsAg solutions, temperature and chaotropic agents, it is less probable that the HBsAg aggregate is produced during the process. To test whether aggregation takes place in vivo, crude yeast extract containing the expressed HBsAg was fractioned on a Sephacryl S-400 column just after cell disruption, and each fraction immunopurified individually. As a result, the HBsAg aggregate was isolated from a fraction corresponding to the elution of large particle aggregates only, not native HBsAg particles. It was biologically active, which demonstrates aggregate formation by specific assembly of partially or wholly folded HBsAg intermediates.     

Sodium dodecylsulfate polyacrylamide gel electrophoresis of recombinant hepatitis B surface antigen particles

To investigate the factors leading to broadening of the recombinant hepatitis B surface antigen (HBsAg) peak in size-exclusion chromatography, the HBsAg particles eluting in different regions of the peak were subjected here to electrophoretic analysis. In nonreduced samples, the 24-kD band corresponding to the S monomer was detected when excessively large amounts of HBsAg were loaded onto the gel. Hence, some monomers are not disulfide-crosslinked in assembled particles. On the other hand, the results of alkylation experiments indicated the presence of free sulfhydryl group(s) in a little portion of freshly-purified HBsAg which was retarded on the size-exclusion chromatographic column and had significant antigenicity. This fraction of HBsAg was shown to be oligomeric and capable of spontaneous assembly into higher-order structures during aging.     

A highly efficient integrated chromatographic procedure for the purification of recombinant hepatitis B surface antigen from Hansenula polymorpha

The high expression level of recombinant hepatitis B surface antigen obtained from Hansenula polymorpha yeast cell (Hans-HBsAg) made it possible to produce HBsAg vaccine in a large scale and by cost-effective process. However, the present available purification process was somewhat tedious, time-consuming and difficult to scale up. To improve the purification efficiency and simplify the purification process, an integrated chromatographic process was developed and optimized. The downstream process included ion-exchange chromatography (IEC), hydrophobic interaction chromatography (HIC) and gel filtration chromatography (GFC). A series of chromatographic adsorbents were evaluated for their performances on the purification of Hans-HBsAg, and then the suitable adsorbents for IEC and HIC were screened out, respectively. After clarification by centrifugation, the supernatant of cell disruption (SCD) was purified by standard chromatographic steps, IEC on DEAE Sepharose FF, HIC on Butyl-S-QZT and GFC on Sepharose 4FF. Furthermore, HBsAg recovery, purification factor (PF) and purity during the downstream process were evaluated with enzyme-linked immunosorption assay (ELISA), sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance size-exclusion chromatography (HPSEC). The results demonstrated that in the scale of 550ml SCD, the total HBsAg recovery and PF of the whole procedure were about 21.0+/-0.9% and 80.7+/-8.4 (n=3) respectively, with the purity of above 99%. This new downstream process was efficient, reproducible and relatively easy to be scaled up.     

待孕夫妇乙肝表面抗原及乙肝表面抗体阳性情况分析

目的 分析与探讨待孕夫妇乙肝表面抗原及乙肝表面抗体检测结果,并研究其对临床孕前检查的影响及评价。方法 随机选取2015‒2017年度在我院进行孕前检查的夫妇2440对（4 880例）为研究对象,按照年度将待孕夫妇分为两组,每组2 440例,两组均加强孕前检查中的乙肝表面抗原（HBsAg）及乙肝表面抗体（HBsAb）的检测。A组为2015年3月‒2016年2月在我院进行乙肝表面抗原及乙肝表面抗体检查的待孕夫妇;B组为2016年3月‒2017年2月在我院进行乙肝表面抗原及乙肝表面抗体检查的待孕夫妇。比较两组待孕夫妇乙肝表面抗原及乙肝表面抗体检测的阳性结果。结果 B组HBsAg阳性率、HBsAb阳性率明显高于A组（6.43% vs 4.63%;62.99% vs 58.44%）,差异有统计学意义（P＜0.05）。B组、A组男性HBsAg阳性率明显高于同组女性（59.87% vs 40.13%;60.18% vs 39.82%）,HBsAb阳性率低于同组女性（46.52% vs 53.48%;47.41% vs 52.59%）,差异均有统计学意义（P＜0.05）。B组、A组高中及以上学历HBsAg阳性率明显低于同组高中以下学历（38.85% vs 61.95%;38.05% vs 61.15%）,高中及以上学历HBsAb阳性率高于同组高中以下学历（53.15% vs 46.84%;51.75% vs 48.25%）,差异均有统计学意义（P＜0.05）结论 目前夫妇乙肝感染仍处于增高趋势,对于进行孕前检查的待孕夫妇加强乙肝表面抗原及乙肝表面抗体的检测,有助于疾病的早期诊断、干预及治疗,能够减少乙肝传播,可有效降低新生儿乙肝发病率,促进优生优育,提高出生人口整体素质。     

乙肝病毒表面抗原持续表达的新致病机制

乙型肝炎表面抗原(HBsAg)持续阳性是控制乙肝中难以解决的重大问题。本研究通过揭示HBsAg致病机制的基础研究,寻找抑制或清除HBsAg的新途径。通过建立有可比性的HBsAg转基因鼠和稳定表达细胞系及相应对照,进行比较转录组学和蛋白质组学研究,发现了HBsAg在HBV慢性感染中的一些新致病机制。其中包括:HBsAg促进肝细胞内CypA分泌,后者可趋化炎症细胞在HBsAg阳性灶周围浸润;在细胞模型中,HBsAg分泌可引起胞内GRP78蛋白下降,导致肝细胞抗凋亡能力减弱;发现HBsAg在细胞中可上调截短的LEF1基因的表达,缺乏活化全长LEF1促成瘤和增殖活性;而肝癌组织中LEF1则倾向于核内分布,并活化Wnt下游基因Cyclin D1与c-myc,有促肿瘤活性。在转基因鼠和细胞模型中都发现了物质和能量代谢相关的基因发生变化,并与临床慢性乙肝患者表现相符。研究中有关CypA的发现提供了抑制HBsAg的新途径;有关代谢的变化提出了改变饮食内容与习惯可能有利于HBsAg阳性感染者的预后。     

Evidence for the denaturation of recombinant hepatitis B surface antigen on aluminium hydroxide gel

Despite the complexity of the subject of protein–alum interactions, a valuable information can be obtained by analyzing the adsorbed and desorbed protein by common physico–chemical methods. In the present work, to approach the adsorption of hepatitis B surface antigen (HBsAg) on alum, the experimental data were supported by complementary analyses of the adsorbed protein by immunoelectron microscopy and the desorbed protein by denaturing size-exclusion chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. First, the depletion of HBsAg was investigated. The aspects assessed were the conditions, recovery and chromatographic performance of the desorbed protein. The results obtained strongly suggested the loss of particulate structure of HBsAg after adsorption on alum. This conclusion was further reinforced by direct immunoelectron microscopic visualization of HBsAg in the adsorbed state.     

Identification of vaccinia promoters by heterologous expression of hepatitis B surface antigen in mouse cells infected by recombinant vaccinia viruses

DNA fragments preceding open reading frames in a conserved segment of the vaccinia virus genome (Plucienniczak A., et al. (1985) Nucleic Acids Res. 13, 985–998) were cloned into plasmids upstream of the S gene of the hepatitis B virus encoding the surface antigen (HBsAg). Recombinant vaccinia virus obtained after insertion of these constructs into the thymidine kinase gene were used to infect mouse 1D cells. HBsAg was assayed in cellular supernatants. A strong promoter was thus identified in a 295 bp fragment preceding the coding region of the 147 kDa subunit of the vaccinia RNA polymerase.