单抗制剂中典型不溶性微粒的形态特征分析

目的：分析单克隆抗体（简称单抗）中典型不溶性微粒图片特征,建立典型不溶性微粒的图谱特征数据库和相应的预警机制。方法：通过采用微流成像技术检测反复冻融、含气泡或硅油、酶解、氧化等不同条件下的单抗中存在的不溶性微粒,筛选关键特征参数用于区别典型不溶性微粒。结果：不同类型不溶性微粒长宽比、密实度、强度、粗糙度和透明度等参数有明显区别,以此可区分不同类型不溶性微粒。此外,获得了不同种类微粒的关键形态特征,初步建立了图谱特征数据库。结论：利用微流成像技术建立对典型不溶性微粒进行比较和分类的方法,可以建立相应预警机制,对单抗中不溶性微粒进行溯源分析和风险评估。     

微流数字成像技术在蛋白药物制剂不溶性微粒分析中的应用

不溶性微粒可以指示注射剂的潜在质量问题和免疫原性风险,是注射剂质量管理中必须评估的质量指标。微流数字成像(MDI)技术是检测不溶性微粒的新方法,相较于不溶性微粒检测“金标准”的光阻法,除了可以提供颗粒的大小和数量信息外,还可以通过高分辨图像获得颗粒种类和形状等特性数据,并且所需样本量少,特别适用于蛋白药物注射剂的质量分析。文章从不溶性微粒的成因和各国药品监管机构和药典对注射剂不溶性微粒质量控制的技术要求出发,综述了MDI技术在蛋白药物处方筛选和工艺研究中的应用进展,以保障蛋白药物制剂的安全性和有效性。     

折光率对微流成像法检测蛋白制剂不溶性微粒的影响

目的：蛋白制剂中不溶性微粒的含量是衡量样品质量的重要指标之一,为了更为准确地检测不溶性微粒的含量和粒径,本研究探讨了溶液折光率对于微流成像系统检测不溶性微粒的影响。方法：本研究以牛血清白蛋白（BSA）为例,通过常见的外界刺激条件（冷冻-解冻）制备高浓度的蛋白质不溶性微粒,并将此微粒稀释至不同折光率的溶液（由PEG1000、海藻糖制备）中,利用微流成像系统检测不溶性微粒的含量。结果：当溶液的折光率接近蛋白质不溶性微粒折光率时,利用微流成像技术检测的不溶性微粒含量低于实际的微粒含量。此外,随着溶液折光率的增加,采用微流成像技术检测出的不溶性微粒的粒径也随之减小。结论：蛋白质溶液的折光率发生改变,会影响利用微流成像技术检测不溶性微粒的准确性。因此,利用微流成像技术检测蛋白制剂中不溶性微粒时,需要考虑到制剂处方的折光率对于检测不溶性微粒的影响,必要时可以采用稀释的方法降低折光率对蛋白质颗粒的屏蔽作用。     

对6种中药注射剂中不溶性微粒的考察

目的：考察与输液配伍后6种中药注射剂中不溶性微粒的数目。方法：用ZWF—4C型注射波微粒分析仪测定配伍前后的中药注射剂中的不溶性微粒的数目。结果：配伍后液体中不溶性微粒显增加，但大多数均符合《中国药典》规定。结论：检测方法可能会对试验结果产生影响；将中药有效成分支接制成输液将成为注射剂的发展方向。     

一种抗TNFα单抗不同粒径级别蛋白聚体监测结果的比较与评价

目的：探讨在单克隆抗体（单抗）稳定性研究中,分子排阻高效液相色谱法（size exclusion-highperformance liquid chromatography,SEC-HPLC）、微流数字成像（microflow digital imaging,MDI）技术、澄清度及可见异物检查在不同粒径级别蛋白聚体监测中的交互作用。方法：分别采用SEC-HPLC、MDI、澄清度及可见异物检查研究肿瘤坏死因子α（TNFα）靶点单抗在4℃储存6个月、37℃和6000 lx光照条件下储存28 d后,蛋白聚体、不溶性微粒、澄清度及可见异物的不同变化。结果：SEC-HPLC结果表明,与样品在4℃储存6个月的结果相比,抗TNFα单抗的蛋白聚体含量在37℃和6000 lx照度处理28d后均增加均不明显。使用MDI技术可见,抗TNFα单抗经37℃和6000 lx照度处理28 d后,1~10 μm、10 μm以上、25 μm及以上粒径的微粒数量比在4℃储存6个月的样品有明显增多,且增多的微粒主要为蛋白聚体。通过目视法对样品的澄清度和可见异物检查发现,37℃储存和6000 lx照度处理28 d后的抗TNFα单抗澄清度低于4℃储存的样品;各储存条件下的抗TNFα单抗均未检出可见异物。结论：在单抗稳定性研究中,纳米级、微米级蛋白聚体的形成上并不具有一致性,因此,应采用多种方法对蛋白聚集情况进行表征和分析,避免单一方法的局限。     

两种过滤方法对输液中微粒的影响

目的 :比较超滤法和常规三级过滤法对输液中微粒的影响。方法 :用光阻法检查两种不同的过滤方法滤过的输液中微粒数。结果 :常规三级过滤法滤过的 4 7批次的输液平均微粒数为 6 .5 6个 /ml(>10 μm)和 0 .71个 /ml(>2 5 μm) ,超滤法滤过的 6 3批次的输液平均微粒数为 2 .2 9个 /ml(>10 μm)和 0 .2 8个 /ml(>2 5 μm) ,两种方法有显著性差异 (P <0 .0 0 1)。结论 :超滤法明显优于常规三级过滤法。     

净化设施对输液中不溶性微粒的影响

本文就不同的净化条件对输液生产微粒污染的情况进行了考察。对比试验结果表明,单用紫外线照射,其注射液中的不溶性微粒数,是层流型全净化间加紫外线照射的4.6倍。每100ml 中,不溶性微粒多201.6粒.     

浅析配药环境对输液中不溶性微粒的影响

用注射液微粒分析仪测定药物配伍后大输液中不溶性微粒的数量的实验表明，配药环境对配伍后的大输液中的不溶性微粒的影响较大，揭示要提高输液的质量，除坚持规定的质量标准以外，对静脉用药中的不溶性微粒也应加以控制，同时还应有工作条件良好的配药环境以及高素质的配药人员。     

36种注射剂中不溶性微粒的研究

目的：研究36种注射剂中的不溶性微粒现状及解决方法。方法：将36种注射剂按治疗剂量(其中24种溶配于0．9％氯化钠注射液或5％葡萄糖注射液中，12种输液直接测试)，用HIAC Royco8000A仪计数该液中直径≥1，2，3，5，8，10，20，25μm的微粒数；对微粒进行理化性质和显微鉴别；考察精密药液过滤器流速、流量、吸附性和截留作用。结果：11种新药静脉注射剂超过《美国药典》(25版)标准，占实验总数30．56％。不溶性微粒有玻璃碴、活性炭、橡胶屑、毛屑索条和药物残渣；精密药液过滤器的流速、流量符合临床要求，截留率为91．01％～99．97％，未见其有吸附作用。结论：精密药液过滤器可截留注射剂中的有害微粒。     

加药对输液不溶性微粒的影响

目的:考察小容量注射剂及加药环境对输液不溶性微粒的影响情况。方法:取注射用头孢拉定等5种无菌粉末注射剂和地塞米松磷酸钠注射液等5种小容量注射液,分别在病房治疗室和净化洁净室,常规操作下,将无菌粉末注射剂分别加入0.9%氯化钠注射液中,将小容量注射液分别加入5%葡萄糖注射液中,以光阻法测定样品的不溶性微粒。结果:与未加药前的输液比较,加入小容量注射剂后,病房治疗室和净化洁净室制备的样品中,≥10μm的不溶性微粒均有显著增加(P<0.05),≥25μm的不溶性微粒均增加不明显(P>0.05);病房治疗室制备的样品与净化洁净室制备的样品比较,≥10μm的不溶性微粒增加非常显著(P<0.01),≥25μm的不溶性微粒增加不明显(P>0.05)。结论:加入小容量注射剂及非净化病房治疗室中加药,可使输液中≥10μm的不溶性微粒明显增加。     

Submicron Size Particles of a Murine Monoclonal Antibody Are More Immunogenic Than Soluble Oligomers or Micron Size Particles Upon Subcutaneous Administration in Mice

Protein aggregates are one of the several risk factors for undesired immunogenicity of biopharmaceuticals. However, it remains unclear which features determine whether aggregates will trigger an unwanted immune response. The aim of this study was to determine the effect of aggregates' size on their relative immunogenicity. A monoclonal murine IgG1 was stressed by exposure to low pH and elevated temperature followed by stirring to obtain aggregates widely differing in size. Aggregate fractions enriched in soluble oligomers, submicron size particles and micron size particles were isolated via centrifugation or size-exclusion chromatography and characterized physicochemically. The secondary and tertiary structures of aggregates were altered in a similar way for all the fractions, while no substantial chemical degradation was observed. Development of anti-drug antibodies was measured after subcutaneous administration of each enriched fraction to BALB/c mice. Among all tested fractions, the most immunogenic was the one highly enriched in submicron size particles (～100-1000 nm). Fractions composed of micron size (>1-100 μm) particles or soluble oligomers (<100 nm) were not immunogenic under the dosing regimen studied in this work. These results show that aggregate size is an important factor for protein immunogenicity.     

单克隆抗体纯化研究进展

综述了单克隆抗体的纯化技术,讨论了各单元操作的关键问题和解决方法,并重点介绍了模拟移动床色谱、双水相萃取、膜色谱等操作简单、能连续生产、低成本的纯化技术。     

Protein Structural Conformation and Not Second Virial Coefficient Relates to Long-Term Irreversible Aggregation of a Monoclonal Antibody and Ovalbumin in Solution

Purpose The purpose of the study was to investigate the relationship of the second virial coefficient, B₂₂, to the extent of irreversible protein aggregation upon storage. Methods A monoclonal antibody and ovalbumin were incubated at 37°C (3 months) under various solution conditions to monitor the extent of aggregation. The B₂₂ values of these proteins were determined under similar solution conditions by a modified method of flow-mode static light scattering. The conformation of these proteins was studied using circular dichroism (CD) spectroscopy and second-derivative Fourier transform infrared spectroscopy. Results Both proteins readily aggregated at pH 4.0 (no aggregation observed at pH 7.4); the extent of aggregation varied with the ionic strength and the presence of cosolutes (sucrose, glycine, and Tween 80). Debye plots of the monoclonal antibody showed moderate attractive interactions at pH 7.4, whereas, at pH 4.0, nonlinear plots were obtained, indicating self-association. CD studies showed partially unfolded structure of antibody at pH 4.0 compared with that at pH 7.4. In the case of ovalbumin, similar B₂₂ values were obtained in all solution conditions irrespective of whether the protein aggregated or not. CD studies of ovalbumin indicated the presence of a fraction of completely unfolded as well as partially unfolded species at pH 4.0 compared with that at pH 7.4. Conclusions The formation of a structurally altered state is a must for irreversible aggregation to proceed. Because this aggregation-prone species could be an unfolded species present in a small fraction compared with that of the native state or it could be a partially unfolded state whose net interactions are not significantly different compared with those of the native state, yet the structural changes are sufficient to lead to long-term aggregation, it is unlikely that B₂₂ will correlate with long-term aggregation.     

Identification of Sites of Degradation in a Therapeutic Monoclonal Antibody by Peptide Mapping

A peptide mapping procedure was developed to locate regions of a monoclonal antibody, OKT3, that undergo chemical modification as the molecule degrades upon storage. The structures of these peptide degradation products were investigated. Deamidation at specific asparagine residues and oxidation of a cysteine and several methionines were found to be major routes of OKT3 degradation. A unique chain cross-linked degradation product was also observed and characterized. Changing the storage conditions of the antibody affected the relative distribution of degradation products. These results were useful in the development of more stable formulations for OKT3, and the methods can be used in the characterization of other monoclonal antibodies intended for therapeutic use.     

Structural Characterization of a Recombinant Monoclonal Antibody by Electrospray Time-of-Flight Mass Spectrometry

Purpose The aim of this study was to perform structural characterization of a recombinant monoclonal antibody (MAb), huN901, by electrospray time-of-flight mass spectrometry (ESI-TOFMS) using both “top-down” and “bottom-up” approaches.Methods In the top-down approach, the molecular masses of the deglycosylated huN901 and the light and heavy chains of the antibody were measured by direct infusion MS and liquid chromatography–mass spectrometry (LC–MS). In the bottom-up approach, trypsin and Asp-N protease were used to digest the separated, reduced and alkylated light and heavy chains followed by LC–MS analysis of the digests.Results The primary structure and post-translational modifications of huN901 were characterized by both top-down and bottom-up MS approaches. Modifications of N-terminal pyroglutamate formation, cleavage of C-terminal lysine, glycosylation, and deamidation were identified in the antibody heavy chain by both protein mass measurement and peptide mapping. No modifications were found in the complementarity determining regions (CDRs) of both chains. Both trypsin and Asp-N protease digestion had an average sequence recovery of 97%, and generated complimentary mapping results with complete sequence recovery.Conclusions ESI-TOFMS is a superior tool to characterize MAb and other complex protein pharmaceuticals.     

The Deleterious Effects of Shiga Toxin Type 2 Are Neutralized In Vitro by FabF8:Stx2 Recombinant Monoclonal Antibody

Hemolytic Uremic Syndrome (HUS) associated with Shiga-toxigenic Escherichia coli (STEC) infections is the principal cause of acute renal injury in pediatric age groups. Shiga toxin type 2 (Stx2) has in vitro cytotoxic effects on kidney cells, including human glomerular endothelial (HGEC) and Vero cells. Neither a licensed vaccine nor effective therapy for HUS is available for humans. Recombinant antibodies against Stx2, produced in bacteria, appeared as the utmost tool to prevent HUS. Therefore, in this work, a recombinant FabF8:Stx2 was selected from a human Fab antibody library by phage display, characterized, and analyzed for its ability to neutralize the Stx activity from different STEC-Stx2 and Stx1/Stx2 producing strains in a gold standard Vero cell assay, and the Stx2 cytotoxic effects on primary cultures of HGEC. This recombinant Fab showed a dissociation constant of 13.8 nM and a half maximum effective concentration (EC₅₀) of 160 ng/mL to Stx2. Additionally, FabF8:Stx2 neutralized, in different percentages, the cytotoxic effects of Stx2 and Stx1/2 from different STEC strains on Vero cells. Moreover, it significantly prevented the deleterious effects of Stx2 in a dose-dependent manner (up to 83%) in HGEC and protected this cell up to 90% from apoptosis and necrosis. Therefore, this novel and simple anti-Stx2 biomolecule will allow further investigation as a new therapeutic option that could improve STEC and HUS patient outcomes.     

Determination of the Origin of Charge Heterogeneity in a Murine Monoclonal Antibody

Purpose. The aim of this study was to elucidate the molecular basis of charge heterogeneity found in a purified monoclonal IgG₁ antibody, MMA383. Methods. Cation exchange chromatography (CEX) and isoelectric focusing (IEF) were used to monitor charge heterogeneity. CEX in conjunction with carboxypeptidase B digests of the antibody was used to determine the contribution of C-terminal lysines to MMA383 charge heterogeneity. Potential chemical degradation sites were identified by peptide mapping of individual chains, with peptide identification by mass spectrometry (MALDI-TOF MS). Peptide sequencing was used to determine specific deamidation sites. Binding constants of predominant isoforms were compared by surface plasmon resonance (SPR). Results. Extensive charge heterogeneity of purified MMA383 was detected by CEX and IEF. Removal of C-terminal lysines simplified the IEF pattern to nine predominant isoforms. Quantitation of isoaspartate in each of the isoforms indicated deamidation of MMA383 as a major cause of charge heterogeneity. CEX of the individual isoform chains suggested the presence of one deamidation site on each of the heavy and light chains. The two sites of deamidation were identified using peptide mapping, sequencing and mass spectrometry. SPR results showed no significant difference in the binding parameters among the isoforms. Conclusions. C-terminal lysine microheterogeneity and deamidation of Asn141 in the heavy chain and Asn161 in the light chain are the major causes of MMA383 charge heterogeneity. Identification of the two deamidation sites will allow replacement of these amino acids in order to create a product less susceptible to degradation.     

应用单克隆抗体研究寻常性银屑病患者外周血中T细胞及其亚群

随机选择30例寻常性银屑病患者和10例正常人,以抗人T细胞表面抗原的单克隆抗体CD_3,CD_4和CD_8用间接免疫荧光法检测其外周血T细胞及其亚群。患者分成7组,进行期、静止期、退行期,点滴状型和斑块状型,受损面积不足10％和10％以上。每组10例。对照组为10例健康成人。结果表明:1.与对照组相比,各组外周血CD_3~+、CD_4~+和CD_8~+细胞百分率及CD_4~+/CD_8~+细胞比率未见明显差异(均P>0.05)。2.点滴状与斑块型组间及受损面积不足10％与10％以上组间的CD_3~+、CD_4~+和CD_8~+细胞百分率及CD_4~+/CD_8~+细胞比率未见明显差异(均P>0.05)。3.进行期和静止期组CD_4~+/CD_8~+细胞比率,经方差分析证实明显地低于退行期组(F=3.73 P<0.05)。结合该发现,就寻常性银屑病的发病机理进行了分析和讨论。     

Application of Electrospray Mass Spectrometry (ES-MS) for the Analysis of Monoclonal Antibody Fc Subunits

Pharmaceutical Research -