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.     

利用假病毒法检测重组人乳头瘤病毒双价(16/18型)疫苗的免疫原性

目的建立并验证重组人乳头瘤病毒双价(16/18型)疫苗中和滴度的检测方法 ,并且利用此假病毒法进行免疫原性研究。方法建立并优化以ZsGreen假病毒为基础的中和实验(ZsGreen法)测定血清中和滴度,比较荧光显微镜观察与微流式细胞分析法、流式细胞分析法的差异,并对专属性、精密度、耐用性、假病毒稳定性和不同细胞代次的影响进行了方法学验证。结果ZsGreen法的HPV16/18假病毒最佳接种量为1 600 TCID50,HPV16型与HPV18型无交叉,具有良好的专属性和精密度,采用不同细胞代次与不同批次假病毒进行检测,均能获得较好的重复性。结论 ZsGreen法假病毒中和滴度检测法准确可靠、重复性好,经方法学验证后此法适用于疫苗的免疫原性研究。     

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.     

人乳头状瘤病毒16、45和58型假病毒小鼠感染模型的建立

目的 建立人乳头状瘤病毒(HPV)假病毒小鼠感染模型.方法 将密码子优化的HPV衣壳蛋白基因表达质粒和荧光素酶报告基因表达质粒共转染293FT细胞,48 h后收集裂解细胞,收获假病毒,并对假病毒滴度进行测定.试验小鼠皮下注射甲羟孕酮醋酸酯,4d后阴道灌注壬苯醇醚.9,并在6 h后阴道灌注假病毒,7d后阴道灌注荧光素酶底物,并检测荧光素酶报告基因的表达情况.结果 成功制备了3种型别(HPV16、HPV45和HPV58)的假病毒,其滴度分别为3.7×108TU/ml、1.5×108TU/ml和1.2×108TU/ml.在3种假病毒感染的小鼠体内可见发光区域,其荧光信号强度分别为1.779×106p/s、5.738×105p/s和1.829×106p/s.结论 成功建立了HPV16、45和58型的小鼠感染模型,为HPV感染干预研究、疫苗评价及预防药物的筛选奠定基础.     

HPV31型L2保守中和表位可诱发广谱中和抗体

目的研究人乳头瘤病毒31型(HPV31)次要外壳蛋白L2保守中和表位的免疫活性及诱发抗体的中和范围。方法合成法获得HPV31 L2 aa.17-40多肽,用EDC法偶联KLH,联合弗氏佐剂免疫新西兰大白兔,用假病毒中和实验检测免疫血清对来自α4、α7、α9、α10及β1亚属的多个HPV型别的中和抗体。结果 HPV31 L2-KLH偶联肽可在新西兰大白兔体内诱发针对至少17种HPV型别的广谱中和抗体,其中HPV31的中和抗体滴度最高,HPV5/45/57的次之。结论首次发现HPV31 L2保守中和表位免疫血清具有广谱中和活性,为基于该表位的广谱HPV疫苗研发奠定了基础。     

埃博拉病毒包膜蛋白GP基因DNA疫苗诱导小鼠产生高滴度中和抗体

目的探讨埃扎伊尔-埃博拉病毒(Zaire Ebolavirus)包膜蛋白(GP)DNA疫苗诱导小鼠产生中和抗体的特性及研制埃博拉病毒DNA疫苗的可行性。方法构建埃博拉病毒包膜蛋白GP真核表达质粒Peak13CD5LGP,采用100μg剂量的质粒免疫小鼠,以纯化的埃博拉病毒包膜蛋白亚单位融合蛋白(GP1-Fc)作为抗原,通过ELISA检测及Western blot验证测定血清抗体滴度及特异性。结果 100μg质粒免疫小鼠3次后,小鼠血清中GP中和抗体滴度达到1∶2 000。结论编码埃博拉病毒包膜蛋白GP的DNA疫苗(pEAK13CD5LGP)能够诱导小鼠产生高滴度和持久的中和抗体,作为埃博拉病毒疫苗具有潜在的应用价值。     

HPV16假病毒制作方法优化

目的为了优化HPV16假病毒制作方法。方法本实验用L1/L2结构蛋白质粒和p CMV-Gluc质粒,从融合试剂,结构质粒与报告质粒比例,细胞接种密度和收获时间等4个方面优化了HPV16假病毒的制作过程,ELISA验证不同抗体水平下假病毒检出效果。结果最优条件分别为E498b,结构质粒与报告质粒2:1,293FT细胞接种密度50%,收获时间48h或72h能够达到最佳包装效率。优化后的假病毒TCID50能够达到105.55,血清ELISA滴度分别为1:2000;1:8000;1:16000,中和实验ID50分别为90,270和810,具有很好的区分度。结论证明该优化方法现实可行,为HPV假病毒生产和中和抗体检测提供了一定的参考意义,为后续病毒试验提供了依据。     

人乳头瘤病毒L2 蛋白的病毒样颗粒疫苗研究

目的:构建乙肝病毒核心抗原(HBcAg)与人乳头瘤病毒(HPV)L2抗原的融合蛋白,在大肠杆菌中重组表达形成病毒样颗粒结构;通过小鼠模型检测HBc-L2融合蛋白的免疫原性,并研究免疫后获得的小鼠血清对HPV假病毒的中和效力。方法:通过DNA合成构建16型人乳头瘤病毒L2基因片段与HBcAg基因的融合基因,将其克隆至表达载体p ET9a并在大肠杆菌中进行HBc-L2融合蛋白表达;将经纯化、鉴定后的融合蛋白免疫BALB/c小鼠,用间接ELISA方法检测小鼠血清中针对L2抗原的抗体效价,并分别研究小鼠血清对16型和18型HPV假病毒的中和效力。结果:HBc-L2融合基因经大肠杆菌系统表达形成可溶性蛋白,经硫酸铵沉淀和CL-4B凝胶分离纯化后获得纯度80%的HBc-L2蛋白;分子筛高效液相色谱-多角度激光光散射(SEC-MALS)联用技术和透射电子显微镜的分析结果表明,HBc-L2融合蛋白在表达过程中自动组装形成稳定的病毒样颗粒;将纯化后的HBc-L2蛋白免疫BALB/c小鼠可获得针对L2抗原的高滴度抗体,且小鼠血清具有中和16和18型两种假病毒的中和抗体活性。结论:HBc-L2病毒样颗粒可以有效地增强L2抗原的免疫原性,并可刺激机体产生针对多型HPV的免疫保护力,是一个具有潜力的新型广谱HPV疫苗。     

新型甲型H1N1流感病毒HA基因DNA疫苗诱导小鼠产生中和抗体

目的 探讨新型甲型流感病毒(2009H1N1)血凝素(HA)DNA疫苗诱导小鼠产生中和抗体特性.方法 构建2009H1N1或1918甲型流感病毒(1918H1N1)HA蛋白表达质粒2009HA和1918HA,采用25μg或200μg剂量2009HA质粒免疫小鼠,以2009HA或1918HA蛋白为包被抗原,测定小鼠血清中2009HA抗体总量或交叉反应抗体含量,分别用2009H1N1和1918H1N1两种假病毒(pp)测定抗体中和活性.结果 25 μg或200μg的2009HA质粒加强免疫小鼠后,4～16周内两组小鼠血清中2009HA总抗体水平以及对2009H1N1pp的中和抗体滴度相似(P>0.05),都含有与1918HA蛋白交叉反应抗体,对1918H1N1pp的交叉中和抗体滴度相似(P>0.05).结论 小剂量2009HA质粒DNA疫苗能够诱导小鼠产生持久的高水平中和抗体,对于预防新现流感病毒具有潜在应用价值.     

人乳头状瘤病毒(HPV)16L1病毒样颗粒蛋白与HPV16L1基因联合免疫的体液免疫反应及其抗体的体外中和实验

目的用含有编码人乳头状瘤病毒(HPV)16L1和HPV16L1病毒样颗粒(VLP)蛋白联合免疫小鼠,与用HPV16L1重组表达质粒比较,观察VLP蛋白免疫对免疫小鼠产生抗体的增强作用,以及抗体的体外中和作用,寻找研制HPV16感染的预防性疫苗的有效途径。方法将c57BL／6小鼠,随机分为4组：Ⅰ组：pcDNA-L1(100μl/鼠),Ⅱ组：pcDNA—L1(70μl/鼠) HPV16K1 VLP,Ⅲ组：pcDNA3.1(100μl/鼠)空质粒,Ⅳ组：PBS缓冲液。质粒免疫3次,间隔3周。ELISA法检测其血清抗体,红细胞凝集实验和HPV16病毒样颗粒结合抑制实验体外检测抗体的中和活性。结果pcDNA-L1 HPV16L1 VLP较pcDNA—L1免疫组,3次免疫后的抗体水平均增高,尤其以第2次和第3次免疫后的抗体水平增加更显著。pcDNA—L1 HPV16L1 VLP联合免疫组血清的抑制活性高于pcDNA—L1免疫组,且．He[a细胞结合抑制实验染色呈阴性。结论HPV16L1 VLP联合免疫可以增加目的抗原的中和抗体产生,可能是HPV16有效预防性疫苗研制的更有希望的策略。     

Reactivity of human sera in a sensitive, high-throughput pseudovirus-based papillomavirus neutralization assay for HPV16 and HPV18

Sensitive high-throughput neutralization assays, based upon pseudoviruses carrying a secreted alkaline phosphatase (SEAP) reporter gene, were developed and validated for human papillomavirus (HPV)16, HPV18, and bovine papillomavirus 1 (BPV1). SEAP pseudoviruses were produced by transient transfection of codon-modified papillomavirus structural genes into an SV40 T antigen expressing line derived from 293 cells, yielding sufficient pseudovirus from one flask for thousands of titrations. In a 96-well plate format, in this initial characterization, the assay was reproducible and appears to be as sensitive as, but more specific than, a standard papillomavirus-like particle (VLP)-based enzyme-linked immunosorbent assay (ELISA). The neutralization assay detected type-specific HPV16 or HPV18 neutralizing antibodies (titers of 160-10240) in sera of the majority of a group of women infected with the corresponding HPV type, but not in virgin women. Sera from HPV16 VLP vaccinees had high anti-HPV16 neutralizing titers (mean: 45000; range: 5120-163840), but no anti-HPV18 neutralizing activity. The SEAP pseudovirus-based neutralization assay should be a practical method for quantifying potentially protective antibody responses in HPV natural history and prophylactic vaccine studies.     

Binding and neutralization efficiencies of monoclonal antibodies, Fab fragments, and scFv specific for L1 epitopes on the capsid of infectious HPV particles

We compared the neutralization abilities of individual monoclonal antibodies (MAb) of two large panels reactive with L1 epitopes of HPV-11 or HPV-16. Binding titers were compared using both L1-only VLPs and L1/L2 pseudovirions. While the VLPs were antigenically similar to the pseudovirions, clear differences in the surface exposure of some epitopes were evident with the HPV-16 particles. To determine whether all antibody binding events are equivalent in their neutralizing effect on infectious HPV virions or pseudovirions, the binding and neutralization titers for individual MAbs were used to calculate the relative neutralization efficiency for each antibody. HPV neutralization was achieved by all MAbs capable of strong binding to either linear or conformation-sensitive epitopes on pseudovirus particles. Our data suggest, however, that some L1 epitopes may be more neutralization-sensitive than other surface epitopes, in that successful infection can be blocked by varying degrees of epitope saturation. Additionally, the effective neutralization of virions by several monovalent Fab fragments and single-chain variable fragments (scFv) demonstrates that viral neutralization does not require HPV particle aggregation or L1 crosslinking. Identification of capsid protein structures rich in neutralization-sensitive epitopes may aid in the development of improved recombinant vaccines capable of eliciting effective and long-term antibody-mediated protection against multiple HPV types.     

Measurement of the humoral immune response following an incident human papillomavirus type 16 or 18 infection in young women by a pseudovirion-based neutralizing antibody assay

We have evaluated a neutralizing antibody assay which uses human papillomavirus (HPV) type 16 (HPV-16) and HPV-18 pseudovirions carrying a secretory alkaline phosphatase reporter gene and which can potentially measure functionally relevant HPV type-specific neutralizing antibodies. The reproducibility of the assay was excellent; for HPV-16, the intra- and interassay kappa values were 0.95 and 0.90, respectively; and for HPV-18, the corresponding values were 0.90 and 0.90. This assay was used to describe the kinetics of the neutralizing antibody response in a cohort of 42 young women who were recruited soon after first intercourse and who first tested positive for HPV-16 DNA or HPV-18 DNA, or both, during follow-up. Most women seroconverted following the first detection of type-specific HPV DNA and remained seropositive until the end of follow-up. Our findings are broadly consistent with those of two other cohort studies which have measured the serological response following an incident infection by using the technically simpler virus-like-particle-based enzyme-linked immunosorbent assay.     

Randomized trial of the immunogenicity and safety of the Hepatitis B vaccine given in an accelerated schedule coadministered with the human papillomavirus type 16/18 AS04-adjuvanted cervical cancer vaccine

The human papillomavirus type 16/18 (HPV-16/18) AS04-adjuvanted cervical cancer vaccine is licensed for females aged 10 years and above and is therefore likely to be coadministered with other licensed vaccines, such as hepatitis B. In this randomized, open-label study, we compared the immunogenicity of the hepatitis B vaccine administered alone (HepB group) or with the HPV-16/18 AS04-adjuvanted vaccine (HepB+HPV group) in healthy women aged 20 to 25 years (clinical trial NCT00637195). The hepatitis B vaccine was given at 0, 1, 2, and 12 months (an accelerated schedule which may be required by women at high risk), and the HPV-16/18 vaccine was given at 0, 1, and 6 months. One month after the third dose of hepatitis B vaccine, in the according-to-protocol cohort (n = 72 HepB+HPV; n = 76 HepB), hepatitis B seroprotection rates (titer of ≥10 mIU/ml) were 96.4% (95% confidence interval [CI], 87.5 to 99.6) and 96.9% (CI, 89.2 to 99.6) in the HepB+HPV and HepB groups, respectively, in women initially seronegative for anti-hepatitis B surface antigen (HBs) and anti-hepatitis B core antigen (HBc). Corresponding geometric mean titers of anti-HBs antibodies were 60.2 mIU/ml (CI, 40.0 to 90.5) and 71.3 mIU/ml (CI, 53.9 to 94.3). Anti-HBs antibody titers rose substantially after the fourth dose of hepatitis B vaccine. All women initially seronegative for anti-HPV-16 and anti-HPV-18 antibodies seroconverted after the second HPV-16/18 vaccine dose and remained seropositive up to 1 month after the third dose. Both vaccines were generally well tolerated, with no difference in reactogenicity between groups. In conclusion, coadministration of the HPV-16/18 AS04-adjuvanted vaccine did not affect the immunogenicity or safety of the hepatitis B vaccine administered in an accelerated schedule in young women.     

Sustained immunogenicity and efficacy of the HPV-16/18 AS04-adjuvanted vaccine: up to 8.4 years of follow-up

Prophylactic human papillomavirus (HPV) vaccines are now available and vaccination programs are being widely implemented, targeting adolescent girls prior to sexual debut. Since the risk of HPV exposure persists throughout a woman's sexual life, the duration of protection provided by vaccination is critical to the overall vaccine effectiveness. We report the long-term efficacy and immunogenicity of the HPV-16/18 AS04-adjuvanted vaccine (Cervarix (?) ) up to 8.4 y after the first vaccine dose. In an initial placebo-controlled study performed in US, Canada and Brazil, women aged 15-25 y with normal cervical cytology, HPV-16/18 seronegative by ELISA, DNA-negative for 14 oncogenic HPV types by PCR, received either the HPV-16/18 vaccine or placebo (n = 1,113). Subjects were followed up to 6.4 y after the first dose (n = 776). We report an additional 2-y follow-up for women enrolled from the Brazilian centers from the initial study (n = 436). During the current follow-up study (HPV-023, NCT00518336), no new infection or lesions associated with HPV-16/18 occurred in the vaccine group. Vaccine efficacy over the entire follow-up (up to 8.4 y) was 95.1% (84.6, 99.0) for incident infection, 100% (79.8, 100) for 6-mo persistent infection, 100% (56.1, 100) for 12-mo persistent infection and 100% (< 0, 100) for CIN2+ associated with HPV-16/18. All women in the vaccine group remained seropositive to both HPV-16/18, with antibody titers for total and neutralizing antibodies remaining several-folds above natural infection levels. The safety profile was clinically acceptable for both vaccine and control groups. This is, to date, the longest follow-up study for a licensed cervical cancer vaccine.     

A peptide-based Plasmodium falciparum circumsporozoite assay to test for serum antibody responses to pre-erythrocyte malaria vaccines

Various pre-erythrocyte malaria vaccines are currently in clinical development, and among these is the adenovirus serotype 35-based circumsporozoite (CS) vaccine produced on PER.C6 cells. Although the immunological correlate of protection against malaria remains to be established, the CS antibody titer is a good marker for evaluation of candidate vaccines. Here we describe the validation of an anti-Plasmodium falciparum circumsporozoite antibody enzyme-linked immunosorbent assay (ELISA) based on the binding of antibodies to a peptide antigen mimicking the CS repeat region. The interassay variability was determined to be below a coefficient of variation (CV) of 15%, and sensitivity was sufficient to detect low antibody titers in subjects from endemic regions. Antibody titers were in agreement with total antibody responses to the whole CS protein. Due to its simplicity and high performance, the ELISA is an easy and rapid method for assessment of pre-erythrocyte malaria vaccines based on CS.     

Sourcing of the WHO human papillomavirus type 18 international standards for HPV antibody levels

BackgroundHPV serology is important for studies of vaccine immunogenicity, but can not be performed in a comparable manner without international standardisation.ObjectivesTo find suitable candidate sera from naturally infected persons for use as International Standards (IS) for antibodies to high-risk HPVs, with priority for HPV-18.Study design946 healthy Thai women (median age 44, range 18–83) and 61 cervical cancer patients were screened using an HPV pseudovirion-Luminex assay to detect antibodies to genital (HPV-6,-11,-16,-18,-31,-33,-45,-52,-58,-68) and non-genital HPV types (HPV-5,-15,-32,-38 and -76). Suitable candidate sera should ideally be mono-specific (have reactivity against only one genital HPV) and have high antibody levels that are stable over time.ResultsSeroprevalences of HPV-16,-31,-52 and -58 were at least twice as high among cancer patients compared to healthy individuals. Thirteen healthy women who met the IS inclusion criteria in initial testing also consented to blood-bag donations. Donations from 2 women with high HPV-18 Ab titers were pooled to the HPV-18 candidate IS, later established as the WHO official IS for HPV antibodies. Sera that could potentially be used as candidate IS for other oncogenic HPVs have also been identified.ConclusionsIn the Thai population, seroepidemiology implicated HPV types HPV-16,-31,-52 and -58 as particularly associated with cervical cancer. A well characterized cohort study has allowed sourcing of materials for an IS for HPV-18 antibodies and could conceivably be used for IS for other HPV types as well.     

含HPV16L1基因重组腺病毒和1型重组AAV载体联合免疫效果的研究

目的 对表达HPV16L1抗原的重组腺病毒及1型重组AAV载体联合免疫效果进行研究.方法 分别构建含密码子优化型HPVl6LI基因重组腺病毒rAd-mod.HPV16L1及1型重组从V载体rAAV1-mod-HPV 16L1,将纯化的重组AAV病毒载体以肌注及滴鼻途径单独及联合免疫C57BL/6小鼠,使用体外中和实验检测各组小鼠血清中特异性中和抗体.结果 rAAV1-med-HPV16L1单独及与rAd-mod-HPV16L1联合肌注可诱导高滴度的血清中和抗体,在初免后第16周抗体滴度显著高于其他免疫组,联合肌注组诱导的抗体滴度高于单独肌注组;重组病毒联合滴鼻虽能产生一定的免疫加强作用,但抗体滴度仍显著低于rAAV1-mod-HPV16L1单独及联合肌注组.结论 型重组从V载体联合重组腺病毒以初免.加强模式肌注可诱导更高滴度的血清中和抗体.