Vero细胞在无血清条件下制备乙型脑炎灭活疫苗

目的 探索Vero细胞在无血清条件下制备乙型脑炎灭活疫苗的工艺. 方法 用无血清培养基培养Vero细胞,并将乙型脑炎病毒P3V2株毒种接种于培养的Vero细胞,观察细胞和病毒的生长情况.收获病毒液,通过灭活、纯化制备乙型脑炎灭活疫苗,检测疫苗各项指标,并与有血清培养工艺制备的疫苗(2013年生产的疫苗)进行比较.结果 无血清培养基培养的Vero细胞生长良好,培养5d的细胞呈致密单层生长.3批无血清培养工艺制备的疫苗的第1、2和3次收获液的平均病毒滴度分别为8.847、8.319和7.194 lgLD50/ml.3批无血清培养工艺制备的疫苗半成品的平均抗原含量(1.51 EU/ml)与有血清培养工艺制备的疫苗(1.41 EU/ml)相当,但前者的宿主细胞蛋白含量(19.69 μg/L)则明显低于后者(63.90 μg/L).结论 乙型脑炎病毒可在无血清Vero细胞中良好生长,Vero细胞无血清培养工艺制备乙型脑炎灭活疫苗是可行的.     

动物源性透明质酸钠的病毒灭活工艺

为确保动物组织来源透明质酸钠的安全性,本研究选择有效的病毒灭活工艺并进行验证。所用动物组织为鸡冠,选择小鼠脑脊髓炎病毒、水泡性口炎病毒、猴空泡病毒40和伪狂犬病毒作为相关的指示病毒。选择透明质酸钠制备工艺中的酶解工艺作为可能灭活病毒的工艺,酶解工艺对小鼠脑脊髓炎病毒、水泡性口炎病毒、猴空泡病毒40和伪狂犬病毒的平均灭活对数值分别为6.125、5.438、5.792和5.250 lgTCID50/0.1 ml。     

细胞工厂在乙型脑炎减毒活疫苗生产中的应用

目的  采用40层细胞工厂（CF40）替代15 L转瓶工艺制备乙型脑炎（乙脑）减毒活疫苗。方法  分别采用CF40和15 L转瓶工艺制备乙脑减毒活疫苗,通过显微镜观察和细胞计数来考察细胞质量。病毒收获时观察细胞病变情况,并对2种工艺制备的原液、半成品以及成品进行病毒滴度检测对比,成品37 ℃放置7 d考察成品热稳定性。结果  两种工艺相比,细胞工厂内单位面积内细胞数量差异存在统计学意义（P＜0.05》）,生长一致性和单只地鼠制备的细胞数量均优于15 L转瓶;CF40和15 L转瓶制备的单一病毒收获液平均滴度分别为7.59 lgPFU/ml和7.56 lgPFU/ml,没有显著差异(P＞0.05),但CF40单一病毒收获液收率一致性更好;两种工艺制备的原液、半成品、成品滴度以及7 d后37 ℃热稳定性均符合企业注册标准规定。结论  使用CF40制备乙脑减毒活疫苗是可行的,并且在产品收率和一致性方面优于15 L转瓶工艺。     

麻疹、腮腺炎、风疹和水痘联合减毒活疫苗的研制

目的 建立麻疹、腮腺炎、风疹和水痘(measles,mumps,rubella and varicella,MMRV)联合减毒活疫苗的生产工艺和检定方法.方法 采用麻疹病毒沪-191株、腮腺炎病毒S79株、风疹病毒BRDⅡ株、水痘-带状疱疹病毒北京84-7株,在原代鸡胚细胞或人胚肺二倍体细胞2BS株中制备高滴度疫苗病毒原液.观察4种原液按不同比例稀释配制后病毒的滴度变化和相互干扰现象,确定MMRV疫苗中4种原液的配制比例,并筛选适宜保护剂,建立最佳冻干工艺.同时,建立MMRV联合减毒活疫苗的检定方法.采用t检验对结果进行比较.结果 选择最佳配制比例、保护剂和冻干工艺制备出连续多批MMRV疫苗,按国家药典要求检定全部合格.其中连续3批疫苗经国家检定机构检定合格:麻疹病毒基础滴度和37℃放置7d后的滴度分别≥3.9和≥3.5 lg半数细胞培养感染量(50％ cell culture infective dose,CCID50)/ml,腮腺炎病毒≥5.0和≥4.7 lgCCID50/ml,风疹病毒≥5.0和≥4.8 lgCCID50/ml,水痘病毒≥4.5和≥4.4 lg噬斑形成单位/ml.用建立的方法检测MMRV疫苗,结果4种病毒滴度实测值与理论值之间的差异无统计学意义(t值为0.149～1.838,P值均＞0.05).结论 建立了稳定、可行的MMRV疫苗生产工艺和检定方法.     

柯萨奇病毒A组16型感染性滴度检测用国家参考品的制备及标定

目的 制备柯萨奇病毒A组16型(coxsackievirus A16,CA16)感染性滴度检测用国家参考品,为CA16疫苗生产过程中的病毒滴度控制和CA16疫苗的免疫效果评价提供国家参考品.方法 将验证合格的CA16(C1亚型)培养液分装(0.5 ml/支)制成候选参考品.3个独立实验室分别对候选参考品进行协作标定,用细胞培养法检测CA16感染性滴度,用Behrens-K(a)rber法计算半数细胞感染量(50％ cell culture infective does,CCID50).同时,将CA16参考品分别置于-20、4、22～25(室温)和37℃条件下或反复冻融,进行热稳定性、长期稳定性和冻存稳定性研究.结果 制备的CA16参考品的病毒滴度为(6.80±0.95) lgCCID50/ml.CA16参考品于-60℃保存12个月、-20℃保存6个月和4℃保存28 d后的病毒滴度无显著下降,表明稳定性较好;在22～25℃(室温)和37℃条件下,CA16参考品每天的病毒滴度损失率分别为3.4％和4.4％,而且分别保存27和21 d后病毒滴度无明显下降;对CA16参考品反复冻融的病毒滴度损失率为4.8％/次.结论 成功制备了CA16感染性滴度检测用候选国家参考品,将CA16参考品赋值确定为(6.80±0.95) lgCCID50/ml.     

两种工艺制备的麻疹减毒活疫苗加速稳定性可比性研究

目的  通过强制降解试验,对细胞工厂与转瓶培养两种工艺制备的麻疹减毒活疫苗进行加速稳定性可比性研究。方法  取细胞工厂与转瓶培养工艺制备的麻疹减毒活疫苗单次收获液和原液各3批于25 ℃保存10 d,疫苗成品3批于37 ℃保存10 d。按照中国药典2015版三部和企业标准进行病毒滴度检定。利用Minitab 19比较两种工艺产品的病毒滴度降解曲线。结果  所有样品的降解曲线均符合麻疹病毒的热敏感性。2种工艺制备的麻疹减毒活疫苗单次收获液病毒滴度第1组分别下降1.51和1.56 lg细胞培养半数感染量（CCID₅₀）/ml,第2组均下降1.33 lg CCID₅₀/ml,第3组均下降1.54 lg,原液分别下降1.20和1.43 lg CCID₅₀/ml,成品分别下降1.33和1.30 lg CCID₅₀/ml。2种工艺产品的降解曲线相似。结论   细胞工厂与转瓶培养工艺生产的麻疹减毒活疫苗具有相似的加速稳定性。     

口服轮状病毒活疫苗病毒滴度评价国家参考品的制备

目的 制备口服轮状病毒(rotavirus,RV)活疫苗病毒滴度评价的国家参考品.方法 选取检定合格的口服RV活疫苗原液,加入保护剂,1.0 ml/安瓿分装,冷冻干燥,制备病毒滴度参考品.用微量细胞病变法检测参考品的病毒滴度,用Karber法计算半数细胞培养感染量(50％ cell culture infective dose,CCID50).由3家实验室对参考品的病毒滴度进行协同标定,采用单因素方差分析和最小显著差数法对3家实验室的标定结果进行统计学分析.另外,将参考品于-20℃放置1年、4℃放置1年、37℃放置14d、-60℃放置2年,测定病毒滴度,分析参考品的热稳定性和长期稳定性.结果 经单因素方差分析比较,3家实验室检测结果的差异无统计学意义(F=0.379,P=0.686).采用最小显著差数法对3家实验室检测结果的均值进行两两比较,差异亦无统计学意义(s(x)值均为0.078 2,P值均＞0.05).参考品的平均病毒滴度为6.5 lgCCID50/ml,于不同温度放置一段时间后病毒滴度下降均未超过1.0 lgCCID50/ml.长期稳定性试验结果的变异系数为4.9％.结论 制备了可用于口服RV活疫苗病毒滴度检测的国家参考品.     

腮腺炎病毒在转瓶和细胞工厂中制备的比较

目的 比较15 L转瓶及40层细胞工厂工艺制备腮腺炎减毒活疫苗的病变情况、病毒滴度和原液各项质量指标。方法 分别采用15 L转瓶及40层细胞工厂培养原代鸡胚细胞1～3 d后感染S79株腮腺炎病毒,继续培养至5～7 d收获病毒液。两种培养方式收获的腮腺炎病毒单次收获液分别合并后获得疫苗原液,并进行相关检定。结果 转瓶收获的单次病毒液0和21 d检定的平均滴度分别为6.6、6.1 lg半数细胞培养感染量（50% cell culture infective dose,CCID₅₀）/ml。细胞工厂收获的单次病毒液0和21 d检定的平均滴度分别为6.8、6.2 lgCCID₅₀/ml。两种方式制备的腮腺炎减毒活疫苗原液各项质量指标均合格。结论 应用40层细胞工厂工艺制备腮腺炎减毒活疫苗的细胞病变情况及单次病毒收获液滴度均优于15 L转瓶培养工艺,此实验为40层细胞工厂制备腮腺炎减毒活疫苗的大规模生产及工艺改进奠定了基础。     

用于荧光抗体试验的狂犬病病毒的灭活

试验采用狂犬病病毒CVS株及衔毒,用含20％正常灭活兔血清的PBS将感染狂犬病病毒的鼠脑制成20％悬液。乳鼠脑内滴定CVS株的LD_(50)为10~(9.1)/ml,街毒为10~(6.0)/ml。     

小儿止喘泡腾片的研制和质量控制

目的：研究小儿止喘泡腾片的制备及质量控制标准。方法：设计处方和制备工艺,应用反相高效液相色谱法一次性完成多组份药物含量测定。结果：氧茶碱、盐酸溴己新及马采酸氟笨那敏线性范围分剐为62．5～625μg／ml(r=0．9992)、12．5～25μg／ml（r=0．9996)、1．25～12．5μg／ml(r=0．9998)。回收率和RSD值分别为99．12％、0．98％;98．85％、1．04％;98．03％、1．02％、结论：该制剂性质稳定,配方合理。含量测定方法简便快捷,具有临床应用价值。     

Spray-drying of proteins: effects of sorbitol and trehalose on aggregation and FT-IR amide I spectrum of an immunoglobulin G.

An immunoglobulin G (IgG) was spray-dried on a Buchi 190 laboratory spray-dryer at inlet and outlet air temperatures of 130 and 190 degrees C, respectively. The IgG solution contains initially 115 mg/ml IgG plus 50 mg/ml sorbitol. After dialysis, at least 80% of low molecular weight component was removed. After spray-drying the dialyzed IgG and immediate redissolution of the powder, an increase in aggregates from 1 to 17% occurred. A major shift towards increase beta-sheet structure was detected in the spray-dried solid, which, however, reverted to native structure on redissolution of the powder. A correlation between aggregation determined by size exclusion chromatography and alterations in secondary structure determined by Fourier transformation infra-red spectroscopy could not therefore be established. On spray-drying a non-dialyzed, sorbitol-containing IgG only some 0.7% aggregates were formed. The sorbitol is therefore evidently able to stabilize partially the IgG during the process of spray-drying. Addition of trehalose to the liquid feed produced quantitatively the same stabilizing action on the IgG during spray-drying as did the sorbitol. This finding again points towards a water replacement stabilization mechanism. The IgG spray-dried powder prepared from the dialyzed liquid feed showed continued substantial aggregation on dry storage at 25 degrees C. This was substantially less in the non-dialyzed, sorbitol-containing spray-dried powder. Addition of trehalose to both dialyzed and non-dialyzed system produced substantial improvement in storage stability and reduction in aggregate formation in storage. The quantitative stabilizing effect of the trehalose was only slightly higher than that of the sorbitol. Taken together, these results indicate that both the sorbitol and trehalose stabilize the IgG primarily by a water replacement mechanism rather than by glassy immobilization. The relevance of this work is its questioning of the importance of the usually considered dominance of glassy stabilization of protein in dried systems of high glass transition temperature, such as trehalose. The low glass transition temperature sorbitol produces almost equal process and storage stability in this case.     

Reducing anti-DT IgG concentrations to improve the efficacy of a diphtheria fusion protein

Preformed antidiphtheria toxin (anti-DT) IgG limits the development of diphtheria fusion proteins because the anti-DT IgG binds and removes the diphtheria fusion protein from the circulation. In our phase I trial of DT-granulocyte macrophage colony stimulating factor (GMCSF), a truncated DT linked to human GMCSF, in relapsed or refractory acute myeloid leukemia, patients with high concentrations of preexisting anti-DT IgG (>2.5 microg/ml) had significantly lower DT-GMCSF concentrations. This study details the fate of anti-DT IgG during the patient's treatment with DT-GMCSF and describes how we could lower anti-DT IgG concentrations and increase the patient's exposure to DT-GMCSF. Using an enzyme immunoassay, we measured anti-DT IgG concentrations before the first cycle of treatment (baseline) and on day 2 (after one dose of DT-GMCSF) and on day 5 (after four doses of DT-GMCSF). Thirty-three patients with relapsed or refractory acute myeloid leukemia in the phase 1 trial received DT-GMCSF at doses from 1 to 5 microg/kg/day intravenously for 5 days. The mean anti-DT IgG concentration pretherapy was 1.3 microg/ml (range: undetectable to 7.8) and significantly decreased to a mean concentration of 0.7 microg/ml on day 2 (P=0.007) and to 0.5 microg/ml on day 5 (P<0.0001). In two individuals in whom we measured DT-GMCSF concentrations on day 1 and day 5, we observed that a decrease in anti-DT IgG concentrations was associated with an increase in DT-GMCSF concentrations. No relationship was observed between dose of DT-GMCSF and the absolute change in anti-DT IgG concentrations on day 2 (r=-0.01, P=0.98) or day 5 (r=-0.12, P=0.53). For patients with high baseline anti-DT IgG concentrations, a single dose of DT-GMCSF could be used to lower the anti-DT IgG concentrations and potentially result in a significant increase in DT-GMCSF concentrations and efficacy.     

Stabilization of IgG by supercritical fluid drying: optimization of formulation and process parameters.

The aim of this study was to stabilize human serum immunoglobulin G (IgG) by a supercritical fluid (SCF) drying process. Solutions containing IgG (20mg/ml) and trehalose or hydroxypropyl-beta-cyclodextrin in a 1:4 (w/w) ratio were sprayed into a SCF phase consisting of CO(2) and ethanol at 100bar and 37 degrees C. Initially, a set of drying conditions previously developed to successfully stabilize lysozyme and myogobin formulations was used [N. Jovanovi?, A. Bouchard, G.W. Hofland, G.J. Witkamp, D.J.A. Crommelin, W. Jiskoot, Eur. J. Pharm. Sci. 27 (2006) 336-345]. Dried formulations were analyzed by Karl Fisher titration, scanning electron microscopy, X-ray powder diffraction, and modulated DSC. Protein structure in the solid-state was studied by FTIR and after reconstitution by UV/Vis, circular dichroism and fluorescence spectroscopy, GPC and SDS-PAGE. When IgG was dried under the above-mentioned conditions, substantial amounts of insoluble aggregates were formed. Addition of buffer helped to reduce the fraction of insoluble material but not of soluble aggregates. Full stabilization could be achieved by adjusting the process conditions: drying without ethanol while keeping the other conditions the same, or drying with ethanol at a temperature below the critical point (20 degrees C). In conclusion, it is possible to stabilize human IgG by SCF drying provided that the formulation and process conditions are tailored to meet the specific requirements of the protein.     

Adjuvant and immuno-suppressive effect of six monophthalates in a subcutaneous injection model with BALB/c mice.

The prevalence of allergic airway diseases is rapidly increasing in Western Europe and North America. This increase in disease prevalence may be associated with environmental pollutants. The present study investigated the adjuvant and immuno-suppressive effect of a series of monophthalates which are considered to be important metabolites of commonly used phthalate plasticizers. The effects were studied in a screening model. Ovalbumin (OA), used as the model antigen, was injected subcutaneously in the neck region of BALB/cJ mice with or without one of the test substances, mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBnP), mono-n-octyl phthalate (MnOP), mono-2-ethylhexyl phthalate (MEHP), mono-iso-nonyl phthalate (MiNP) or mono-iso-decyl phthalate (MiDP). The levels of OA-specific IgE, IgG1 and IgG2a in sera were measured by ELISA. Immuno-suppressive effect, defined as a statistically significant reduction in IgE or IgG1 antibody production, was observed with MEHP (1000 microg/ml, IgE and IgG1), MnOP (1000 microg/ml, IgE and IgG1), MiNP (1000 microg/ml, IgE and 10 microg/ml, IgG1) and MiDP (100 microg/ml, IgE and IgG1). Adjuvant effect, defined as a statistically significant increase in IgE or IgG1 antibody level, occurred with MEHP (10 microg/ml, IgE), MnOP (100 microg/ml, and 10 microg/ml, IgG1) and MiNP (100 microg/ml, IgE). No statistically significant immune modulating effect was seen with MBnP and MnBP.     

RESPONSES OF HUMAN ARTERIAL MUSCLE TO STABLE VASOACTIVE SUBSTANCES RELEASED FROM HUMAN PLATELETS BY COLLAGEN AND HEAT AGGREGATED IgG

The supernatant solutions obtained after aggregation or sonication of washed human platelets were superfused over preparations of human isolated digital arteries using a small volume bioassay method. The agents released from the platelets caused strong contractions of the artery strips. Platelet aggregation induced by 10 micrograms/ml collagen or by 100 micrograms/ml heat aggregated IgG, released 31.5% and 38.5% respectively, of the contractile activity produced by sonication of the platelets. The quantitative contractile effect of supernatants from platelets aggregated by 50 micrograms/ml IgG was significantly less than that for 100 micrograms/ml HA IgG. Similarly, the maximum contractile effect of supernatants from platelets aggregated by 300 ng/ml collagen was significantly less than that for 1 microgram/ml collagen. This suggests that the concentration of contractile agents released from platelets depends on the concentration of aggregating stimulus. Comparison with concentration-effect curves for exogenous serotonin suggests that if the contractility of the platelet supernatant occurring after sonication of platelets is solely due to serotonin, then it is present in a concentration of approximately 3.3 X 10(-6) mol/l (6.6 nmol per 10(9) platelets). It is suggested from this study that in certain clinical situations characterized by hypertension, and in which circulating immune complexes have been found, in vivo platelet activation by immune complexes may be releasing sufficient concentrations of serotonin to constrict peripheral blood vessels and contribute to the hypertension.     

Repeated hemoperfusion and continuous arteriovenous hemofiltration in a paraquat poisoned patient

Prompt hemodialysis or hemoperfusion can be of value during the first 24 hours after paraquat ingestion particularly when the patient has developed acute renal failure. However, many cases of paraquat poisoning occur in areas where hemoperfusion facilities are unavailable. In contrast, continuous arteriovenous hemofiltration (CAVH) could be instituted easily. We have measured the removal of paraquat from the body by CAVH in a 46 year old male cane farmer who ingested 70 ml, 20% paraquat and died twelve days later from pulmonary fibrosis. Renal failure developed rapidly. Concentrations of paraquat were measured by an indirect competitive ELISA using a murine paraquat monoclonal IgG antibody. Hemoperfusion was performed daily for five days, beginning 78 hours post-ingestion. By 180 hours, when the patient was in respiratory failure, hemoperfusion was replaced with CAVH which was continued for 46 hours. During this time interval, 1.1 mg paraquat was recovered in the hemofiltrate and 1.56 mg paraquat in the urine. The extraction of paraquat by the hemofilter was close to 100%. The plasma clearance of paraquat across the hemofilter was 6.1 ml/min and the renal clearance was 8.2 ml/min. The mean hemoperfusion clearance of paraquat was 50 ml/min and the total amount of paraquat removed by the 34 hours of hemoperfusion was 9 mg. Because of the relative ease with which CAVH can be performed, its low cost, compared to that of hemoperfusion or hemodialysis, and the continuous nature of the procedure, CAVH may be worth considering in paraquat poisoning. It could be used particularly in those patients who have developed renal failure or while patients are being prepared for hemoperfusion.     

Primary antibody response to keyhole limpet hemocyanin in rat as a model for immunotoxicity evaluation

To address current regulatory expectations on immunotoxicity testing of new chemicals, we describe an animal model that measures the primary antibody response to the T-cell dependent antigen, keyhole limpet hemocyanin (KLH). Single immunization with KLH by either footpad (300microg/rat) or intravenous (300microg/kg) route in Sprague Dawley rats resulted in increased germinal center formation in the spleen and a robust anti-KLH IgM (70-388microg/ml) and IgG (230-470microg/ml) antibody response with peak detection on Days 5 and 14 post-immunization, respectively. Subcutaneous immunization with KLH (300microg/kg) resulted in a much weaker anti-KLH IgM and IgG (< or =20microg/ml) antibody response with no detectable increase in splenic germinal center formation. The utility of a rat KLH immunization model in detecting immunosuppression was evaluated with the known immunosuppressive drugs: cyclosporin, azathioprine and prednisolone. Rats, treated with drug at a maximum tolerated dose, were immunized with KLH by footpad or intravenous injection and serum samples were collected at various intervals up to 2 weeks post-immunization. Additional study parameters included terminal body weight, hematology and/or histopathology. All three drugs inhibited the IgM (60%) and IgG (> or =90%) antibody responses in the absence of overt toxicity based on evaluation of the standard toxicology parameters. In conclusion, measurement of a rat primary antibody response to KLH by ELISA is a reliable and readily standardized method for assessing immunotoxicity of pharmaceuticals.     

重组戊型肝炎病毒P179-海藻酸钠/壳聚糖微球混悬制剂的制备及其免疫效果

目的 制备吸附重组戊型肝炎病毒(hepatitis E virus,HEV)P179抗原的海藻酸钠/壳聚糖微球混悬制剂,并观察其免疫效果。方法 乳化法制备海藻酸钠/壳聚糖微球,采用不同海藻酸钠浓度、混合乳化剂添加量、混合乳化剂亲水亲油平衡值设计正交试验,确定最佳制备工艺参数。将重组HEV P179抗原吸附在最佳工艺制备的微球表面,制备吸附重组HEV P179的海藻酸钠/壳聚糖微球混悬制剂,皮下多点免疫BALB/c小鼠,测定其诱导小鼠产生特异性IgG抗体的能力,与同剂量含弗氏佐剂的重组HEV P179免疫制剂对比。结果 经正交试验确定乳化最佳工艺参数为:海藻酸钠质量分数1%、混合乳化剂体积分数2%,混合乳化剂亲水亲油平衡值4。制备的微球平均粒径为6.73 μm(分布范围3.90~9.10 μm,方差1.78 μm),形态较为均一,透射电镜观察结果与双层球体及内部疏松多孔的微球结构特点相符。用此条件制备抗原质量浓度为500 μg/ml的混悬制剂,微球对抗原的吸附率为90.64%。免疫效果观察试验结果表明,皮下多点免疫试验中微球制剂诱导特异性IgG抗体的能力优于含弗氏佐剂抗原。结论 成功制备了吸附重组HEV P179的海藻酸钠/壳聚糖微球混悬制剂,且诱导产生特异性IgG抗体的能力优于含弗氏佐剂抗原,为其在新型实验动物超敏制剂中的应用奠定了基础。     

检测黑猩猩腺病毒68型抗原的双抗体夹心ELISA的建立

目的  建立定量黑猩猩腺病毒68型（chimpanzee adenovirus type 68，AdC68）含量的双抗体夹心ELISA，并验证其可行性。方法  用表达绿色荧光蛋白（green fluorescence protein，GFP）的非复制型AdC68（AdC68GFP）感染HEK293细胞，收获病变细胞并进行超速离心纯化AdC68GFP。用纯化AdC68GFP免疫家兔制备抗AdC68GFP抗体。以抗AdC68GFP抗体为包被抗体，辣根过氧化物酶标记的抗腺病毒HEXON IgG为酶标抗体，建立双抗体夹心ELISA，确定该法的线性范围，并验证该法的准确度、精密度、专属性和适用性。结果  纯化AdC68GFP的蛋白浓度为38.8 µg/ml，其中HEK293细胞的蛋白浓度低于0.3 µg/ml。双抗体夹心ELISA的最适包被抗体和酶标抗体浓度分别为1∶50和1∶500。该法的线性范围为0.06~3.88 µg/ml，线性相关系数为0.999 6。高、低浓度AdC68GFP样品的回收率分别为93.17%和94.33%，变异系数分别为6.72%和3.44%。该法可特异性检测AdC68GFP抗原，未发现与HEK293细胞蛋白发生交叉反应。应用该法检测AdC68GFP纯化过程中的样品可反映病毒的纯化效果。结论  建立的双抗体夹心ELISA具有良好的准确度、精密度和特异性，可用于AdC68纯化工艺过程中对病毒蛋白含量的快速检测。     

Determination of slime-producing S. epidermidis specific antibodies in human immunoglobulin preparations and blood sera by an enzyme immunoassay: correlation of antibody titers with opsonic activity and application to preterm neonates

Slime-producing Staphylococcus epidermidis is responsible for severe infections in immunocompromised patients and, particularly, in premature infants who are transiently deficient in IgG. A sulfated polysaccharide with molecular mass of 20-kDa (20-kDa PS) has been recognized as the major polysaccharide component and antigenic determinant of S. epidermidis extracellular slime layer. The presence of adequate amounts of antibodies to 20-kDa PS in patients' sera would be of importance to prevent or treat slime-producing S. epidermidis bacteremia. Administration of intravenous immunoglobulin (IVIG) is considered to be a reasonable IgG replacement therapy and has been widely used to prevent or treat neonatal sepsis. Clinical trials have shown conflicting results on the efficacy of IVIGs and this phenomenon has been attributed to the variability of IVIG preparations in the content and opsonic activity of IgG against microorganisms of clinical importance. Monitoring of antibodies to distinct bacterial macromolecules, which are species-specific and responsible for bacterial infections, has not been performed previously. A highly precise and repeatable enzyme immunoassay was developed to determine quantitatively the levels of antibodies against the 20-kDa PS of S. epidermidis slime. The amount of 20-kDa PS specific antibodies found in 27 lots of an IVIG preparation (Sandoglobulin) correlated well with their in vitro opsonic activity against slime-producing S. epidermidis. The majority of lots (75%) having titers higher than 200 units/ml showed significant opsonic activity (50-75%) towards slime-producing S. epidermidis. Sandoglobulin lots with titers higher than 200 units/ml of 20-kDa PS specific IgG were administered as a prophylactic agent to low-birth weight (lower than 1700 g) preterm neonates immediately after birth. The levels of total and 20-kDa PS specific IgG in neonates' blood sera were significantly higher than those found in the control group, even 10 days after the last infusion. The rate of slime-producing S. epidermidis bacteremia in neonates who received IVIG was also considerably lower than those in the control group. The results of this study suggest that specific IgG titers estimated by the developed enzyme immunoassay may well be indicative of the IVIG opsonic activity against slime-producing S. epidermidis. Furthermore, administration of Sandoglobulin with titers higher than a cut-off value of 200 units/ml may significantly protect preterm neonates against slime-producing S. epidermidis bacteremia.