人乳头瘤病毒16型中国株L1基因的体外真核表达

目的 构建人类乳头瘤病毒16型(HPV16)中国株晚期基因L1的真核表达系统.方法 将HPV16中国株L1基因从pCR2.1/HPV16L1定向亚克隆至pTacer-CMV载体,构建重组质粒pTaeer-CMV/HPV16L1,将重组质粒用脂质体转染N1H3T3、HeLa细胞,用透射电镜、SDS-PAGE、蛋白印迹等方法观察HPV16 L1蛋白的表达.结果 NIH3T3、HeLa细胞经pTacer-CMV/HPV16L1转染后,SDS-PAGE、蛋白印迹等实验显示可表达HPV16 L1蛋白,电镜下可见病毒样颗粒(VLP).结论 pTacer-CMV/HPV16L1构建成功,可在体外表达HPV16中国株L1蛋白.     

食管鳞状上皮细胞癌及癌旁组织中HPV11 L1基因克隆及序列比较

目的 克隆食管癌组织和癌旁组织中HPV11型主要衣壳蛋白L1基因,并比较两个序列间的同源性。方法 以食管癌组织和癌旁组织纯化的总DNA为模板,根据HPV11型L1基因的保守区分段设计引物。分两段扩增HPV L1基因,克隆入质粒载体中,pGEM-3Zf(-)以双脱氧法双向测定目的片段的序列,并按接出该片段的全序列,比较两个序列间的同源性,以及与已知基因序列的差异性。结果 从4例食管癌患者食管癌组织和癌旁组织中,分别克隆到1株HPV11型L1的编码序列M1和M2,两序列间的同源性极高,仅在个别位点存在差异。与GenBank中登录的HPV序列NC001525．1（HPV－11）、M14119．1（HPV－11）和AF217526．1（HPV－11）相比较大部分相同。结论 成功地构建了HPV11型L1基因上游片段pGEM－3Gf(-)和下游片段pGEM-3Zf(-)的重组克隆,为深入研究HPV的感染与食管癌发病机制的关系奠定了基础。     

促进乳头状瘤病毒L1蛋白表达和DNA疫苗免疫效应的研究

目的 探讨促进乳头状瘤病毒（PV）晚期基因L1的蛋白表达和DNA疫苗免疫效应的途径及可能的机制。方法 分别将含人源化优化密码BPVL1-GFP融合基因（HL1-GFP）和野生型BPVL1-GFP融合基因（WE1-GFP）的真核表达质粒体外单独转染或与tRNA^ser真核表达质粒共转染人角质形成细胞HaCAT，荧光显微镜及Western blot方法观察L1-GFP融合蛋白的瞬时表达情况。半定量RT-PCR分析不同PV L1基因mRNA的表达。BALB／c小鼠股四头肌内分别接种野生型、优化密码L1 DNA疫苗，同时将L1 DNA疫苗与tRNA^ser真核表达质粒混合后接种小鼠，观察诱导产生的体液免疫反应。结果 野生型WE1-GFP融合基因在HaCAT细胞中未能有效表达，优化密码HL1-GFP基因在HaCAT细胞中的蛋白表达水平明显增强；但两者在mRNA水平差异无统计学意义。WE1-GFP与tRNA^ser真核表达质粒共转染细胞中L1蛋白的表达较单独转染WE1-GFP基因时增强。动物DNA免疫结果表明，优化密码HE1 DNA疫苗接种可使小鼠特异性L1中和抗体水平明显升高；而野生型WE1 DNA疫苗接种组小鼠仅产生低滴度的L1抗体，WE1 DNA疫苗与tRNA^ser真核表达质粒混合接种使小鼠的L1抗体水平增加。结论 优化密码能显著促进乳头状瘤病毒晚期基因L1在哺乳动物细胞中的表达和DNA疫苗的免疫反应；补充外源tRNA^ser基因能够提高野生型L1基因的蛋白表达和DNA疫苗诱导的体液免疫应答。     

人乳头瘤病毒16型晚期蛋白L1的表达及病毒样颗粒的装配

目的　在昆虫细胞中表达人乳头瘤病毒 16型 (HPV16 )哈尔滨地区分离株的晚期蛋白L1,并分离纯化由L1蛋白在细胞中自主组装成的病毒样颗粒 ,为HPV16预防性疫苗的研制奠定基础。方法　获得含有HPV16L1基因的重组杆状病毒并使目的蛋白L1在昆虫细胞中表达 ;对重组杆状病毒的扩增条件及L1蛋白的表达水平进行优化 ;电镜下观察昆虫细胞中晚期蛋白装配成病毒样颗粒的情况 ,经氯化铯密度梯度纯化病毒样颗粒 ,并经Westernblot进行验证。结果　获得了稳定表达L1蛋白的重组杆状病毒 ;以MOI值为 0 .2感染昆虫细胞可获得较高滴度的重组病毒 ,以MOI值为 10感染昆虫细胞可获得较高水平的L1蛋白表达 ;电镜下可观察到昆虫细胞核内直径为 5 5nm的病毒样颗粒 ;病毒样颗粒可通过氯化铯密度梯度离心获得。结论　获得人乳头瘤病毒哈尔滨地区分离株L1蛋白可在昆虫细胞中自主装配的病毒样颗粒并成功分离纯化。     

人乳头瘤病毒16型结构基因L1在昆虫细胞中的表达及其生物学活性

目的 研究与宫颈癌及人类其它多种组织癌症密切相关的人乳头瘤病毒16型（HPV16）的晚期基因L1的表达及其生物学活性。方法 采用PCR法从pBSSK-B/16L1扩增了来自中国妇女鲍温病组织标本的HPV16晚期基因L1,装入杆状病毒转移载体;在DH10Bac内通过转座子Tn7的介导,使携带有杆状病毒多角体蛋白基因启动子Ppolh的HPV16 L1基因整合入杆状病毒,形成重组杆状病毒;转染昆虫细胞Sf9进行表达;将感染72h的Sf9细胞包埋、切片、染色后,电镜观察。提取L1蛋白,免疫BALB／ c小鼠。结果 重组杆状病毒在Sf9细胞内高效表达出L1蛋白,经Western blot发现能与L1抗体特异地结合;薄层扫描显示所表达的L1蛋白占Sf9细胞总蛋白的比例高达31％。经透射电镜观察表明,在细胞核里有大量的重组杆状病毒形成;并且产生了大量的由HPV16 L1蛋白单体自组装的病毒样颗粒（virus-like particles,VLP)。小鼠免疫实验结果表明,所表达的HPV16 L1蛋白单体自组装的病毒样颗粒（virus-like particles,VLP)。小鼠免疫实验结果表明,所表达的HPV16 L1蛋白具有强免疫原性。结论 此研究为今后L1基因分子流行病学检查、L1蛋白的结构生物学研究、疫苗研制以及HPV相关基础性研究提供了有用的资料。     

HPV16 L1基因的原核表达及免疫反应性鉴定

目的：在大肠杆菌中表达人乳头瘤病毒16型(HPV16)主要衣壳蛋白L1，并鉴定其免疫反应性。方法：将HPV-16L1基因克隆人原核表达载体pThioHisC中，构建重组表达载体。以重组载体分别转化大肠杆菌Top10和DH5α，在IPTG诱导下表达外源基因，用SDS—PAGE和Western blot对表达产物进行鉴定和分析。结果：构建了HPV—16L1基因的原核表达质粒pThioHisC／HPV—16L1，并在大肠杆菌中表达出相对分子质量(Mr)约为70800的蛋白。表达的蛋白能与抗HPV—16L1抗体发生特异性反应。结论：在原核细胞中成功地表达HPV—16L1基因，为HPV—16L1疫苗的研制提供了必要的基础。     

Detection of human papillomavirus types 6 and 11 E4 gene products in condylomata acuminatum.

Polyclonal antiserum to an Escherichia coli-produced beta-galactosidase/E4 fusion protein of human papillomavirus type 6b (antiserum 256), and affinity purified HPV 11 anti-E4 antibodies were tested for reactivity in Western blots with bacterially expressed trpE/E4 fusion proteins of HPV types 6b, 11, 16, and 18. To further characterize the affinity purified anti-E4 antibodies, a dot-immunobinding assay was performed using overlapping synthetic HPV 11 E1E4 peptides as antigens. Protein extracts of condylomata acuminatum from 18 patients containing HPV type 6 or 11 DNA sequences were tested in Western blots using antiserum 256 or affinity purified HPV 11 anti-E4 antibodies. In the Western blots of the trpE proteins, antiserum 256 identified the HPV types 6b and 11 fusion proteins; the affinity purified HPV 11 anti-E4 antibodies identified only the HPV 11 fusion protein. In the dot-immunobinding assay, three HPV 11 peptides were recognized, each containing a shared 8 amino acid sequence that differs significantly from the corresponding sequences of HPV types 6b, 16, or 18. In the Western blots of protein extracts from 18 condylomata acuminatum samples shown to contain HPV types 6 or 11 DNA, putative E4 gene products were identified in six samples by antiserum 256. The affinity purified HPV 11 anti-E4 antibodies identified putative E4 gene products in one of these same six lesions, which was shown to contain HPV 11 sequences by the Southern blot method. All six samples containing E4 gene products were from women. Three of these women were pregnant, one had serum antibodies to the human immunodeficiency virus, and one was a renal transplant recipient receiving glucocorticoids.(ABSTRACT TRUNCATED AT 400 WORDS)     

Human papillomavirus type 11 neutralization in the athymic mouse xenograft system: Correlation with virus-like particle IgG concentration

Neutralization of virus is likely to be necessary for development of an effective prophylactic vaccine against genital human papillomavirus (HPV) infection. Two New Zealand white rabbits were immunized with purified HPV type 11 (HPV 11) virions in Freund's adjuvant. An enzyme linked immunoassay (ELISA) was used to determine the quantity of IgG which recognized the HPV 11 major capsid protein (L1 protein) virus-like particles (VLPs) in the two anti-HPV 11 sera (serum A and serum B). The concentration of HPV 11 L1 VLP-specific IgG in the A and B sera were determined to be 37 and 90 μg per ml, respectively. The A and B sera were used in neutralization experiments in the athymic mouse xenograft system with known quantities of purified HPV 11 virions. The concentration of HPV 11 L1 VLP-specific IgG required to neutralize HPV 11 was determined for each antiserum. This concentration of IgG was approximately 700 to 900 ng per ml. This study demonstrates a positive correlation between the level of HPV 11 L1 VLP-specific IgG in animals immunized with HPV 11 virions and neutralization of HPV 11 in the athymic mouse model. Further studies are needed 1) to determine if sera or genital secretions from other species are neutralizing in the athymic mouse xenograft system, and 2) to determine if the VLP ELISA can be used as a reliable substitute for more cumbersome neutralization assays. J. Med. Virol. 53:185–188, 1997. © 1997 Wiley-Liss, Inc.     

人乳头瘤病毒6b L1/16E7嵌合蛋白的基因克隆和表达

目的 研究HPV6bL1/16E7嵌合蛋白的基因克隆及其在昆虫细胞的表达,为防治尖锐湿疣和宫颈癌的基因工程疫苗研究作准备。方法 用PCR扩增出HPV6bL1/16E7嵌合蛋白基因,将其克隆到杆状病毒转移载体pVL1393,制备重组杆状病毒并感染昆虫细胞表达HPV6bL1/16E7嵌合蛋白。结果 HPV6bL1/16E7嵌合蛋白基因在昆虫细胞中得到了表达,并可自组装形成病毒样颗粒。结果 昆虫细胞表达的HPV6bL1/16E7嵌合病毒样颗粒可进一步用于HPV感染的免疫机理及基因工程疫苗研究。     

小干扰RNA对人乳头状瘤病毒6bE7基因表达的沉默作用

目的研究靶向人乳头状瘤病毒HPV-6b型E7基因的二聚体小干扰RNA(siRNA- HPV-6bE7)对靶基因表达的沉默作用。方法建立并筛选稳定表达HPV-6bE7基因的B16和293T转染细胞株,用脂质体转染法将体外合成的siRNA-HPV-6bE7转染上述细胞株,采用实时荧光定量PCR分析靶基因HPV-6bE7的mRNA表达情况。结果用不同浓度的siRNA-HPV-6bE7转染细胞48 h,50 nmol/L浓度对B16细胞中靶基因表达的抑制作用最强(抑制率87.05%),1nmol/L抑制作用较低(9.14%);而在293T细胞,10nmol/L的siRNA对靶基因表达的抑制效应最大(78.87%),1nmol/L仍有一定抑制作用(46.92%)。50 nmol/L siRNA-HPV-6bE7转染B16细胞后,靶基因的mRNA表达在24 h内开始受抑制(32.47%),48h作用最强(74.72%),96h作用很低(8.91%);25nmol/L和10nmol/L的siRNA转染293T细胞后,均在24h内起效(26.66%、20.31%),抑制作用至少能维持72h(65.93%、35.23%)。结论siRNA-HPV-6bE7对B16和293T细胞外源性靶基因表达均有较强的特异性沉默作用,在不同细胞株达到最大抑制效应的siRNA浓度不同,但时效曲线的变化趋势基本一致,siRNA均在24h内起效,48～72h达到高峰,抑制作用至少能维持72h。本研究结果为下一步在动物或临床进行siRNA干扰试验提供了实验依据。     

悬浮培养昆虫细胞表达重组HPV16 L1蛋白

目的 用悬浮培养昆虫细胞方式表达人乳头瘤病毒16型(HPV16)L1蛋白,为获得病毒样颗粒(VLPs)及进一步深入研究疫苗和诊断试剂盒打基础.方法 优化昆虫细胞Sf9的悬浮培养条件;优化扩增病毒和蛋白的条件;空斑试验测定病毒滴度;SDS-PAGE和Western Blot分析目的蛋白的表达情况;透射电镜观察细胞内HPV16 L1蛋白形成的VLPs.结果 优化后,悬浮培养昆虫细胞初始接种密度为5×105cell/ml,以MOI(Multiplicity ofInfection)=10接种重组病毒rBacV/HPV16 L1,72～84h收获细胞沉淀为最佳.经透射电镜观察,在重组病毒感染的昆虫细胞内,存在HPV16L1蛋白形成的VLPs.结论 优化了细胞悬浮培养、病毒扩增和蛋白表达的条件;电镜观察在重组病毒rBacV/HPV16L1感染的昆虫细胞中,HPV16 L1蛋白可形成VLPs.     

Cloning and expression of the L1 major capsid protein of the human papillomavirus 18 in murine cells

Human papillomavirus (HPV) type 18 is strongly associated with the development of cervical cancer. Studies of a model system with animal papillomaviruses have demonstrated the importance of neutralizing antibodies in preventing papillomavirus-associated disease. The immune response to HPV is poorly understood, and there are non- standardized serological assays to identify HPV infections. In our study, the assessment of antibody responses against HPVs (previously hampered by the lack of viral source) was enabled by the expression of the L1 major capsid viral protein type 18 (HPV18) into L929 murine cells using the pTARGET mammalian expression vector system (MEVS). The cloning was validated by PCR with specific primers for the L1 gene, as well as by enzyme restriction and in situ hybridization. The evidence for the viral cloned gene expression was acquired by RT-PCR. Presence and antigenic properties of the recombinant L1 protein were shown using it as antigen in an indirect enzyme linked immunosorbent assay (ELISA) system. Significantly higher reactivity was noted when the sera samples were from persons infected with HPV18 as compared with the non-infected individuals but a moderately different reactivity was observed when the sera from patients infected with other HPV genotypes were tested. The results showed that the murine transfected cells could be used as antigen in order to detect the presence of the specific antibodies in HPV infected persons.     

沉默URG11基因对前列腺癌LNCaP细胞增殖、迁移与侵袭的影响

 目的: 观察上调基因11(up-regulated gene 11,URG11)在前列腺癌细胞系中的表达及降低URG11表达对人前列腺癌LNCaP细胞增殖和侵袭能力的影响。方法: 用real-time PCR和Western blot检测前列腺癌细胞系和正常前列腺上皮细胞系中URG11 mRNA和蛋白水平;设计针对URG11基因的siRNA靶序列,转染LNCaP细胞,采用流式细胞仪检测细胞周期和凋亡,MTS测定LNCaP细胞增殖能力,划痕和侵袭实验评价LNCaP细胞迁移及侵袭能力。结果: 在LNCaP、DU145、PC3前列腺癌细胞系和RWPE-1正常前列腺上皮细胞系中URG11 mRNA和蛋白表达水平存在显著差异,在前列腺癌细胞中URG11 mRNA和蛋白表达水平明显升高(P<0.05)。与对照组相比,转染URG11 siRNA的LNCaP细胞增殖停滞在G₁/S期并诱导前列腺癌细胞凋亡,转染组的细胞凋亡率为8.79%±0.12%,而且LNCaP肿瘤细胞的迁移及侵袭能力明显下降(P<0.05)。结论: URG11在前列腺癌系中高表达。通过RNAi沉默URG11基因能明显抑制LNCaP细胞增殖和侵袭能力,并诱导细胞凋亡。     

Functional F11L and K1L genes in modified vaccinia virus Ankara restore virus-induced cell motility but not growth in human and murine cells

Modified vaccinia virus Ankara (MVA) was generated by serial passaging in chicken embryo fibroblasts. During this attenuation, MVA lost the capacity to productively grow in human and most other mammalian cell lines, as well as acquiring a multitude of deletions and mutations in the MVA genome. This means that the precise molecular basis for the MVA host-range restriction is still unknown. The vaccinia virus (VACV) genes F11L and K1L are mutated or truncated in MVA. F11L was previously implicated in VACV-induced cell motility and virion maturation. Here, we demonstrate that the restoration of F11L gene expression in MVA rescued virus-induced cell motility, but had no impact on MVA virion maturation and host-range restriction. Additional insertion of the K1L gene, which restores MVA replication in RK-13 cells, was not sufficient to extend MVA growth capacity to other mammalian cells.     

The full-length E1E4 protein of human papillomavirus type 18 modulates differentiation-dependent viral DNA amplification and late gene expression

Activation of the productive phase of the human papillomavirus (HPV) life cycle in differentiated keratinocytes is coincident with high-level expression of E1E4 protein. To determine the role of E1E4 in the HPV replication cycle, we constructed HPV18 mutant genomes in which expression of the full-length E1E4 protein was abrogated. Undifferentiated keratinocytes containing mutant genomes showed enhanced proliferation when compared to cells containing wildtype genomes, but there were no differences in maintenance of viral episomes. Following differentiation, cells with mutant genomes exhibited reduced levels of viral DNA amplification and late gene expression, compared to wildtype genome-containing cells. This indicates that HPV18 E1E4 plays an important role in regulating HPV late functions, and it may also function in the early phase of the replication cycle. Our finding that full-length HPV18 E1E4 protein plays a significant role in promoting viral genome amplification concurs with a similar report with HPV31, but is in contrast to an HPV11 study where viral DNA amplification was not dependent on full-length E1E4 expression, and to HPV16 where only C-terminal truncations in E1E4 abrogated vegetative genome replication. This suggests that type-specific differences exist between various E1E4 proteins.     

HPV6b L1/Ct MOMP多表位嵌合DNA诱导BALB/c小鼠产生特异性细胞免疫的研究

目的 探讨人乳头瘤病毒(HPV)6b结构蛋白L1和沙眼衣原体(Ct)主要外膜蛋白(MOMP)多表位嵌合DNA(HPV6b L1/Ct MOMP)诱导BALB/c小鼠产生特异性细胞免疫效应,及HPV6b L1对Ct MOMP多表位基因诱导细胞免疫的增强作用.方法 将Ct MOMP多表位基因连接在经真核密码子优化的HPV6b L1羧基端,构建嵌合重组质粒pcDNA3.1(+)/HPV6b L1/Ct MOMP多表位,经酶切和测序证实后,转染COS-7细胞,间接免疫荧光鉴定其在真核细胞中的表达;将纯化后的嵌合重组质粒肌肉注射免疫BALB/c小鼠,并设置pcDNA3.1(+)/Ct MOMP多表位质粒、pcD-NA3.1(+)和PBS三组对照.采用0、2、4周免疫程序,DNA剂量为每只150μg/次.于末次免疫后2周,分别用乳酸脱氢酶(LDH)释放法和细胞内细胞因子染色-流式细胞术(ICS-FAGS)检测小鼠脾细胞对Ct MOMP多表位蛋白和HPV6b L1蛋白的特异性CTL活性,胞内细胞因子IFN-γ、IL-4和IL-10产生水平等细胞免疫应答指标.结果免疫后,在效靶比(E∶T)分别为40∶1、20∶1时,pcDNA3.1(+)/HPV6b L1/Ct MOMP多表位嵌合重组质粒免疫组小鼠产生了针对Ct MOMP多表位蛋白特异性CTL杀伤活性(44.56%±4.02%,35.35%±2.89%)和HPV6b L1蛋白特异性CTL杀伤活性(27.08%±2.04%,21.68%±4.06%),与各对照组比较差异有统计学意义(F=72.87,F=114.55,P＜0.05;F=30.04,F=10.47,P＜0.05),且显著高于pcDNA3.1(+)/Ct MOMP多表位质粒组(35.50%±2.68%,30.24%±1.75%;12.27%±3.36%,9.32%±3.07%;P＜0.05);而pcDNA3.1(+)/Ct MOMP多表位质粒组小鼠仅显示了Ct MOMP多表位特异性的CTL杀伤活性,与对照组比较差异也有统计学意义(F=58.85,F=120.21;P＜0.05).胞内细胞因子IFN-γ的产生水平,pcDNA3.1(+)/HPV6b L1/Ct MOMP多表位嵌合质粒组(4.34%±0.06%)高于pcDNA3.1(+)/Ct MOMP多表位质粒组(3.14%±0.18%),与对照组比较差异有统计学意义(F=473.83,P＜0.05),而重组质粒组较空载体组和PBS对照组差异也有统计学意义(F=211.72,P＜0.05);但IL-4和IL-10水平则各组间差异无统计学意义(F=0.97,P＞0.05;F=2.25,P＞0.05).结论 pcDNA3.1(+)/HPV6b L1/Ct MOMP多表位嵌合DNA质粒可诱导BALB/c小鼠同时产生针对HPV6b L1蛋白和Ct MOMP多表位蛋白特异性的细胞免疫效应;真核密码子优化的HPV6b L1能显著增强Ct MOMP 多表位基因诱导的小鼠特异性细胞免疫效应.     

HPV11 mutant virus-like particles elicit immune responses that neutralize virus and delineate a novel neutralizing domain

Characterization of the regions of human papillomaviruses (HPVs) that elicit neutralizing immune responses supports studies on viral infectivity and provides insight for the development and evaluation of prophylactic vaccines. HPV11 is a major etiologic agent of genital warts and a likely vaccine candidate. A conformationally dependent epitope for the binding of three neutralizing monoclonal antibodies (mAbs) has been mapped to residues G(131)T(132) of the L1 major capsid protein. The mAbs bind L1 only when it is assembled into virions or into virus-like particles (VLPs) that mimic the capsid structure. We were interested in identifying other domains of L1 that elicit neutralizing responses. To this end, we have generated a panel of mAbs against VLPs derived from HPV11 L1 harboring a G131S substitution. The new mAbs are unlike the neutralizing mAbs previously mapped to residues G(131)T(132) in that they bind both prototype and HPV11:G131S mutant VLPs. Some of the new mAbs neutralized virus in vitro. We have mapped epitopes for three of these new mAbs, as well as a neutralizing mAb generated against HPV11 virions, by measuring binding to HPV6 VLPs substituted with HPV11-like amino acids. Two regions are critical: one defined by HPV11 L1 residues 263-290 and the other by residues 346-349. mAbs H11.H3 and H11.G131S.G3 bind HPV6 VLPs with substitutions derived from the 346-349 region; in addition, H11.G131S.G3 binds HPV6 VLPs with substitutions derived only from the 263-290 region. Although H11.H3 does not bind HPV6 VLPs with substitutions derived from the 263-290 region, binding to HPV6 VLPs is enhanced when both sets of substitutions are present. mAbs H11.G131S.I1 and H11.G131S.K5 bind HPV6 VLPs with the 263-290 substitutions, but show little binding to HPV6 VLPs with the 346-349 substitutions. However, binding to HPV6 VLPs is enhanced when substitutions at both regions are present. The 346-349 region has not previously been described as eliciting a neutralizing response for any HPV type. In addition, the work demonstrates a complex binding site contributed by two distinct regions of L1.     

Expression and characterization of HPV-16 L1 capsid protein in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

Human papillomaviruses (HPVs) are responsible for the most common human sexually transmitted viral infections. Infection with high-risk HPVs, particularly HPV16, is associated with the development of cervical cancer. The papillomavirus L1 major capsid protein, the basis of the currently marketed vaccines, self-assembles into virus-like particles (VLPs). Here, we describe the expression, purification and characterization of recombinant HPV16 L1 produced by a methylotrophic yeast. A codon-optimized HPV16 L1 gene was cloned into a non-integrative expression vector under the regulation of a methanol-inducible promoter and used to transform competent Pichia pastoris cells. Purification of L1 protein from yeast extracts was performed using heparin–sepharose chromatography, followed by a disassembly/reassembly step. VLPs could be assembled from the purified L1 protein, as demonstrated by electron microscopy. The display of conformational epitopes on the VLPs surface was confirmed by hemagglutination and hemagglutination inhibition assays and by immuno-electron microscopy. This study has implications for the development of an alternative platform for the production of a papillomavirus vaccine that could be provided by public health programs, especially in resource-poor areas, where there is a great demand for low-cost vaccines.