HPV31 L1 C端截短基因可在昆虫细胞表达体系中高水平制备L1 VLP疫苗

目的利用昆虫细胞表达体系制备人乳头瘤病毒(HPV)31 L1病毒样颗粒(VLP)疫苗。方法化学合成法获得昆虫Sf9细胞偏性密码子优化的、C端删除27个氨基酸编码序列的HPV31 L1截短基因(HPV31 L1MΔC),构建重组杆状病毒,感染Sf9细胞进行表达;分别采用超声破碎、含离子型表面活性剂(1%SDS等)或含非离子型表面活性剂(0.5%TritonX-100)的裂解缓冲液,制备细胞裂解上清;氯化铯超速离心法纯化后经动态光散射及透射电子显微镜鉴定;0.1μg的HPV31 L1MΔC VLP于第0和2周肌肉免疫BALB/c小鼠,第4周采集血清分析中和活性。结果 3种裂解方法制备的上清均显示HPV31 L1MΔC蛋白的特异表达,其表达量约占裂解上清总蛋白的10%;采用非离子型表面活性剂获得的裂解上清纯化后,目的蛋白纯度高,产量达11.5 mg/L;纯化蛋白的水化分子直径为103.3 nm,均一性好;电镜分析为直径50～60 nm的VLP。免疫血清中HPV31中和抗体滴度为1 440。结论 HPV31 L1MΔC在昆虫细胞表达体系制备的VLP产量高、免疫原性好,可用于生产含HPV31 L1 VLP的多价疫苗。     

人乳头瘤病毒(HPV)L2肽免疫小鼠诱导的抗体水平与保护作用的关系研究

目的 检测HPV-58 L2 11～200 AA肽在动物体内对HPV的保护效果,并分析疫苗诱导的抗体滴度或中和抗体滴度与疫苗保护作用之间的对应关系.方法 利用大肠杆菌表达HPV-58L2 11～200 AA肽,纯化目的 蛋白并与铝佐剂吸附后免疫小鼠,利用小鼠HPV-58假病毒感染模型检测不同剂量的免疫原对小鼠的保护作用.通过ELISA和假病毒中和抗体检测方法 检测免疫血清中的总抗体水平和中和抗体水平,分析具有保护作用的抗体或中和抗体滴度.结果 当蛋白免疫剂量为8μg时,能够完全保护小鼠不受HPV假病毒的感染.小鼠免疫血清中的中和抗体水平较低,利用已建立的假病毒中和试验方法 检测不到血清中的中和抗体.而利用ELISA检测血清中的总抗体水平结果 显示,免疫血清中的总抗体水平与疫苗的保护效果之间存在对应关系,当抗体滴度大于等于1:25 000时,小鼠体内检测不到荧光信号,能够保护机体不受假病毒的感染.结论 HPV-58 L2 11～200 AA肽能够保护小鼠不受假病毒的感染,L2 11～200 AA肽具有较好的疫苗发展前景,其引发的总抗体水平可以作为评价保护效果的间接指标.     

SARS-CoV-2广谱中和抗体性质鉴定

目的：对严重急性呼吸综合征冠状病毒2(SARS-CoV-2)广谱中和抗体XMA09进行性质鉴定,探究其广谱中和突变株的潜在机制,为SARS-CoV-2的疫苗设计与广谱中和抗体筛选提供参考。方法：通过ExpiCHO真核表达系统与Protein A层析柱表达纯化XMA09蛋白;冷冻电镜技术确定XMA09识别的受体结构域（RBD）上的关键氨基酸位点;间接ELISA与表面等离子共振（SPR）技术检测XMA09对SARS-CoV-2及其突变株Spike蛋白的亲和力;采用基于水疱性口炎病毒（VSV）的假病毒系统检测XMA09对SARS-CoV-2野生型及突变株的中和能力。结果：本研究发现XMA09识别的表位较为保守,对多种突变株Spike蛋白均具有强结合能力,能广谱中和关切突变株（VOCs）,包括广泛流行的Omicron亚突变株BA.4/5。结论：XMA09是SARS-CoV-2广谱中和抗体,具有作为SARS-CoV-2治疗性抗体的潜力,并可为SARS-CoV-2的广谱疫苗设计与抗体药物开发提供参考意义。     

一种直接评价HPV16L1抗体活性的新方法

目的 :以pcDNAL1质粒免疫啮齿类动物 (C5 7BL/ 6 )为模型 ,观察HPV16L1VLP细胞结合抑制实验是否可以用于检测免疫抗体的中和保护作用。方法 :实验组包括Ⅰ组pcDNAL1、Ⅱ组HPV16L1VLP ;Ⅲ组pcDNA3.1。每组动物均为 6只C5 7BL/ 6鼠。每组动物均肌肉注射免疫 3次 ,间隔 3w。末次免疫后 14d眼球后取血并拉颈处死动物 ,进行HPV16L1VLP结合抑制试验 :免疫血清中和HPV16L1VLP ;制备Hela ,EJ和RLC310细胞爬片 ,CS12 13细胞涂片 ;细胞免疫组化染色。结果 :实验组血清中和后Hela细胞呈染色阴性 ,而对照组、不共育组则细胞呈棕黄色。结论 :这说明实验组血清具有抑制VLP与Hela细胞粘附的活性效应。这一方法可能比HAI更能直接反映中和抗体的活性和保护作用。     

HPV16L1／L2蛋白单克隆抗体的制备

用真核表达的ＨＰＶ１６Ｌ１／Ｌ２蛋白作为抗原，经免疫、融合、选择性培养、克隆化等过程，我们建立了两株抗ＨＰＶ１６Ｌ１／Ｌ２蛋白的杂交瘤细胞株（另有数株仍在建株中）。免疫斑点法检测证明，它们产生的抗体，只与ＨＰＶ１６Ｌ１／Ｌ２蛋白起反应，而不与ＨＰＶ１６Ｅ６、Ｅ７蛋白、人血清蛋白和牛血清蛋白起反应。另外，免疫组化试验证明，这种抗体可应用于临床ＨＰＶ１６感染的检验，具有敏感、特异、准确、快捷、经济的优点。     

HIV-1自然感染中的中和抗体反应

中和抗体(Nab)可以防止I型人类免疫缺陷病毒(HIV-1)侵入靶细胞.HIV-1感染数周后即可诱导产生Nab,这些早期抗体只能特异性地中和自体病毒但不能中和异源性病毒.在一些慢性感染者体内则可以检测到可同时中和同源性和异源性病毒的广谱中和抗体(BNab).BNab的靶点通常位于包膜蛋白的保守区域.HIV-1 BNab的产生还受到病毒变异及结构遮盖等因素的限制,同时Nab的中和广度与病毒载量具有相关性.     

16型人乳头瘤病毒（HPV16）中和表位及型内变异分析北大核心CSCD

世界范围内,宫颈癌是妇女第二位高发肿瘤.高危型人乳头瘤病毒（human papilloma-virus,HPV）持续感染是引发宫颈癌的主要原因,在所有高危型HPV中,HPV16流行最广泛.HPV主要衣壳蛋白（major capsid protein,L1）可以自组装成病毒样颗粒（virus-like particles,VLPs）,其形态及抗原性与天然病毒类似,可以刺激机体产生高效价保护性中和抗体.中和表位是HPV VLPs疫苗的结构基础,疫苗的效力主要取决于中和表位的完整性.目前基于中和单抗的HPV16表位研究取得了极大进展.随着免疫压力的增加,HPV16的型内变异株越来越多.1204条HPV16 L1氨基酸序列构建的进化树可以分为4个进化分支.同时,将其与114K参考序列相比,共挑选出8个＂高频突变位点＂,6个＂特有突变位点＂和20个＂表位相关位点＂.HPV诱导的中和抗体绝大多数都是型特异性的,但同一型别内的HPV所诱导的中和抗体对型别内的所有L1变异株是否都能保护尚无定论.剖析HPV16型的抗原表位及型内变异情况对设计高效价、高覆盖率的预防性疫苗至关重要.     

诱导广谱中和抗体的人类免疫缺陷病毒-1疫苗

由于人免疫缺陷病毒(human immunodeficiency virus,HIV)包膜糖蛋白的高度变异性及较弱的免疫原性,研制HIV疫苗遇到了极大的困难,目前还没有有效疫苗.包膜糖蛋白是诱导中和抗体的主要抗原.如何针对包膜蛋白设计出合理的免疫原,诱导具有交叉保护功能的广谱中和抗体已经成为研究HIV疫苗的主要目标.     

HIV-1广谱中和抗体分离鉴定和中和表位特异性研究进展

HIV/AIDS在世界上广泛流行,抗逆转录病毒药物尚无法彻底根除HIV感染,开发新的治疗和预防方法仍然至关重要。不断分离到的广谱中和抗体(bnAb),在抗HIV-1感染和治疗方面的应用日益突出,也为新疫苗的设计带来曙光。本文对近年来bnAb的分离鉴定的技术及中和表位特征研究进展进行简要综述。     

新疆南部地区维吾尔族妇女宫颈癌组织中HPV-16型L2基因多态性分析

目的探讨新疆南部地区维吾尔族妇女宫颈癌组织中人乳头瘤病毒16型(humanpapillomavirus16,HPV16)L2基因的变异,并预测L2蛋白的功能变化。方法从19份中国新疆南部地区维吾尔族妇女宫颈癌活检组织标本中提取DNA,以此DNA为模板,PCR扩增HPV16L2全长基因,PCR产物直接测序或克隆后测序,分析新疆维吾尔族妇女宫颈癌组织HPV16L2基因多态性及HPV16L2蛋白功能的变化。结果PCR检测结果显示宫颈癌组织中HPV16L2阳性率为84.21%(1619);测序和序列分析表明L2基因核苷酸多处发生变异,并引起编码氨基酸的变异;L2基因在核苷酸水平上形成7种突变模式(XJL21～XJL27),各模式与HPV16原型比较,同源性在99.37%～99.79%之间;在氨基酸水平上形成5种突变模式,其中XJL1123突变模式占66.67%(812),是突变的主流模式,各模式与HPV16原型比较,同源性在98.31%～99.58%之间;以上突变引起HPV16L2蛋白疏水性和抗原性的改变,继而改变了L1蛋白的结构及功能。结论中国新疆南部地区维吾尔族妇女宫颈癌组织中HPV16L2基因发生多位点变异,并形成多种突变模式和突变主流模式;这些突变引起HPV16L2蛋白疏水性和抗原性的改变,提示HPV16L2基因突变可能与HPV16的系统发生以及病毒逃避机体免疫识别有关。     

广州地区人腺病毒5型血清中和抗体阳性率初步调查

目的评估广州地区人群中人腺病毒5型（HAdV-5）中和抗体阳性率情况。方法采用以β-半乳糖苷酶（LacZ）为报告基因,结合CMV启动子的人重组腺病毒5型载体,运用化学发光法,检测209份免疫功能正常的成人血清样本中HAdV-5的中和抗体。结果 HAdV-5中和抗体的阳性率为82.3%（172/209）。HAdV-5中和抗体在〈1：20（低滴度）、1：40-1：160（中滴度）、1：320-1：1280（高滴度）、〉1：1280（超高滴度）时均能检测到,而且随着滴度的增加,阳性率逐渐升高。在20～40岁时HAdV-5中和抗体阳性率最高,在〈20岁时HAdV-5阳性率最低。结论广州地区人群中针对HAdV-5的先存中和抗体阳性率高,应用基于该种DNA病毒作为载体进行基因疫苗及基因治疗的研究时,具有一定的局限性。     

The N-terminal region of the human papillomavirus L2 protein contains overlapping binding sites for neutralizing, cross-neutralizing and non-neutralizing antibodies

The N-terminal region of the human papillomavirus (HPV) L2 protein has been shown to contain immune epitopes able to induce the production of neutralizing and cross-neutralizing antibodies (Gambhira et al., 2007; Kawana et al., 1999). Using bacterial thioredoxin as a scaffold, we managed to enhance the immunogenicity of putative L2 neutralizing epitopes, but only a minor fraction of the resulting immune responses was found to be neutralizing (Rubio et al., 2009). To determine the recognition patterns for non-neutralizing, neutralizing and cross-neutralizing antibodies, we isolated and characterized a panel of 46 monoclonal antibodies directed against different HPV16 L2 epitopes. Four of such antibodies proved to be neutralizing, and two of them, both targeting the amino acid (aa) 20-38 region of L2, were found to cross-neutralize a broad range of papillomaviruses. The epitopes recognized by neutralizing and cross-neutralizing antibodies were mapped at high resolution and were found to be characterized by distinct recognition patterns. Even in the case of the L2 20-38 epitope, cross-neutralization of HPV31 pseudovirions proved to be extremely inefficient, and this was found to be primarily due to the lack of a proline residue at position 30. HPV16 specific amino acids in this region also appear to be responsible for the lack of cross-neutralizing activity, thus suggesting a potential immune escape mechanism. For the aa 71-80 region, instead, the data indicate that restriction of neutralization to HPV16 is due to sequence (or structural) differences laying outside of the epitope. Besides providing new insights on the molecular bases of L2-mediated immune reactivity, the present data may pave the way to novel vaccination approaches specifically evoking cross-neutralizing antibody responses.     

Development of a blocking ELISA for detection of serum neutralizing antibodies against porcine circovirus type 2

A monoclonal antibody (Mab)-based blocking ELISA was developed for the detection of serum neutralizing antibodies to porcine circovirus type 2 (PCV2). The Mab with neutralizing activity, which was produced by immunizing a recombinant capsid protein of PCV2 expressed in insect cells, was used as the detector antibody. The assay was evaluated in comparison with a serum neutralization assay, and its sensitivity and specificity were determined to be 98.8% and 88.5%, respectively. A significant positive correlation was found between results of the blocking ELISA and the serum neutralization assay (r = 0.9381). The assay was verified by testing experimental and commercial pig sera. A longitudinal antibody profile showed that serum neutralizing antibodies were detected 2 weeks after vaccination and that the detection rate reached 100% at 4 weeks. The serum neutralizing antibody profile showed a decrease from the age of 4 to 13 weeks, and seroconversion after 13 weeks in pigs from a commercial pig farm. Additionally, the positive detection rate in 703 sera collected from nine commercial pig farms was 73%. This report demonstrates that the assay is a simple, specific, sensitive and convenient method for epidemiological surveys and evaluations of serum neutralizing antibodies against PCV2.     

人乳头状瘤病毒6型类病毒颗粒的制备及其中和抗体的检测

目的 利用大肠杆菌表达系统制备人乳头状瘤病毒6型(human papillomavirus type 6,HPV-6)类病毒颗粒(virus-like particles,VLP)并研究其免疫原性.方法 在大肠杆菌ER2566中表达HPV-6 L1蛋白,并以硫酸铵沉淀、离子交换色谱、疏水相互作用色谱等手段对其进行纯化.纯化后的HPV-6 L1经体外组装形成VLP后以动态光散射,透射电镜对其形态进行检测,并以假病毒中和实验评价HPV-6 L1 VLP在实验动物体内所诱导的抗HPV-6/11中和抗体水平.结果 HPV-6 L1蛋白在大肠杆菌中以可溶形式表达,经过纯化后的HPV-6 L1蛋白可以在体外组装为半径25 nm左右的VLP.该VLP可以在山羊及兔体内诱导高滴度的HPV-6/11中和抗体.结论 大肠杆菌表达系统可以简便高效制备具有免疫原性的HPV-6 VLP,可以用于HPV-6疫苗的研究.     

Detection of HPV types and neutralizing antibodies in Gansu province,China

A total of 82 samples from patients with cervical cancer (Group 1) and 50 samples from patients with other genital diseases (Group 2) were collected in Gansu, China. All 132 samples were tested for HPV DNA with a typing kit that can detect 21 types of HPV, and also tested for neutralizing antibodies against HPV‐16, ‐18, ‐58, ‐45, ‐6, and ‐11 using pseudovirus‐based neutralization assays. The results revealed that 28% (23/82) of sera in Group 1 were positive for type‐specific neutralizing antibodies with a titer range of 160–640, of which 23.2% (19/82), 2.4% (2/82), 2.4% (2/82), 1.2% (1/82), and 1.2% (1/82) were against HPV‐16, ‐58, ‐6, ‐18, and ‐45, respectively. Only one serum (2%) in Group 2 was positive for neutralizing antibodies, which were against HPV‐6 with a titer of 2,560. Overall, 85.4% (70/82) of samples in Group 1 were HPV DNA‐positive, compared with 28% (14/50) of samples in Group 2. The seven most common types detected in Group 1 were HPV‐16 (80%), HPV‐52 (7.1%), HPV‐66 and HPV‐11 (5.7% each), and HPV‐58, HPV‐18, and HPV‐33 (4.3% each), while the four most common types in Group 2 were HPV‐16 (12%), HPV‐52 and HPV‐11 (6% each), and HPV‐68 (4%). The concordance between HPV DNA and corresponding neutralizing antibodies was 32.9% (27/82) with a significant difference (P < 0.005). More specifically, the concordance was 42.7% (35/82) for HPV‐16 in Group 1. The full‐length sequences of six HPV types (HPV‐16, ‐58, ‐33, ‐59, ‐11, and ‐68) were determined and showed 99% identities with their reported genomes. J. Med. Virol. 81:693–702, 2009 © 2009 Wiley‐Liss, Inc.     

Interaction between human papillomavirus type 5 E2 and polo‐like kinase 1

The E2 protein of the papillomavirus plays an essential role in the viral life cycle. Through a yeast two‐hybrid screening, human polo‐like kinase 1 was found to interact with human papillomavirus type 5 E2. Further characterization identified that the domains responsible for the interaction are the transactivation domain of HPV‐5 E2 and the sequence between the kinase and the polo box domains of Plk1. In vivo, Plk1 and HPV‐5 E2 are colocalized at the nuclear speckles. In the skin epithelium not infected with epidermodysplasia verruciformis associated HPVs, Plk1 is expressed in the stratum basale, indicating that the Plk1–HPV‐5 E2 interaction likely occurs in the keratinocytes at the basal layer of the epithelium upon infection of HPV‐5. Both HPV‐5 E2 and Plk1 also interact with the E2 binding domain of Brd4. The E2 binding domain of Brd4 is phosphorylated by Plk1 in vitro, and this phosphorylation event is blocked by the presence of HPV‐5 E2. Hence, these findings suggest the possibility that the cellular function of Brd4 is de‐regulated by forming a complex with HPV‐5 E2 in the infected epithelial cells. J. Med. Virol. 81:536–544, 2009. © 2009 Wiley‐Liss, Inc.     

Antibodies that block virus attachment to vero cells are a major component of the human neutralizing antibody response against dengue virus type 2

Epidemiological data strongly implicate a role for the host humoral immune response in both protection against and exacerbation of dengue virus-caused disease. In an effort to characterize elements of the normal human immune response against dengue virus we have addressed the issue of antibody-mediated neutralization of dengue virus. We show here the ability of both mouse monoclonal antibody 3H5 and human anti-dengue neutralizing sera to block binding of dengue-2 virus to monkey kidney (Vero) cells. Since Vero cells possess virus receptors but not Fc receptors we conclude that the major effect of host neutralizing antibodies is to block virus attachment to Vero cell dengue virus receptors. Analysis of 61 patient antisera yielded good correlation (Pearson's coefficient = 0.90; P < 0.001) between neutralizing activity and ability to block virus-cell attachment suggesting that antibody-mediated neutralization of dengue virus occurs primarily extracellularly and less by a postat-tachment mechanism as has been described for certain other viruses. © 1995 Wiley-Liss, inc.     

Immunoglobulin germline gene polymorphisms influence the function of SARS-CoV-2 neutralizing antibodies

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