中国脑型疟患者恶性疟原虫分离株裂殖子表面蛋白MSP1第16-17区基因和MSP2基因的分子克隆与鉴定

目的 :为设计研制安全有效的人脑型疟疫苗提供理论依据。方法 :根据 MAD2 0株裂殖子表面蛋白 1( MSP1)和 FC2 7株裂殖子表面蛋白 2 ( MSP2 )基因编码区高度保守碱基设计并合成两对引物 ,应用多聚酶链反应 ( PCR)技术对 5例脑型疟患者恶性疟原虫云南省勐腊县勐罕分离株 CMH/ YN和云南省盈江县农场 CYJ/ YN分离株基因组 DNA MSP1第 13- 17区基因和MSP2基因进行扩增 ,并将扩增产物分别经 Eco RI和 Kpn I,Bam HI和 Hind III双酶切后 ,分子定向克隆 M13mp18和 M13mp19载体 ,转染大肠杆菌 ( E.coli) TG1,从含 X- gal和 IPTG的 LB平板上 ,将随机筛选得到的单个无色噬菌斑经 E.coli JM10 3扩增 ,用碱裂解法抽提重组子复制型DNA ( RFDNA)后 ,再分别经 Eco RI和 Kpn I,Bam HI和 Hind III双酶切鉴定。结果 :证实重组子为编码脑型疟患者恶性疟原虫 CMH/ YN和 CYJ/ YN分离株 MSP1第 16- 17区基因和 MSP2基因分子克隆 M13载体。结论 :首次报道确证脑型疟患者恶性疟原虫 CMH/ YN和 CYJ/ YN分离株MSP1第 16- 17区基因和 MSP2基因分别与 MAD2 0株 MSP1和 FC2 7株 MSP2相应基因完全一致。这些发现对研究预防人脑型疟疫苗和建立一种新型脑型疟恶性疟原虫检测方法具有重要意义。     

中国脑型疟患者恶性疟原虫分离株裂殖子表面蛋白MSP1第16—17区基因的分子克隆及序列分析

目的 :为设计研制安全有效的人脑型疟疫苗提供进一步科学依据。方法 :应用多聚酶链反应 ( PCR)技术对中国 5例脑型疟患者恶性疟原虫云南省勐腊县勐罕 CMH/YN分离株和云南省盈江县农场 CYJ/YN分离株基因组 DNA裂殖子表面蛋白 1( MSP1)第 13— 17区基因进行扩增 ,将扩增产物分别经 Eco RI和 Kpn I双酶切后 ,回收的 MSP1第 16— 17区基因分子定向克隆M13mp18和 M13mp19载体 ,按 Sanger双脱氧链终止法进行 DNA序列测定 ,并与 MAD2 0、K1和Wellcome株原型基因进行同源性分析比较。结果 :发现脑型疟患者恶性疟原虫 CMH/YN和 CYJ/YN分离株 MSP1第 16— 17区基因之间的序列完全相同 ,全长为 918bp,编码 30 6个氨基酸 ,含 12个半胱氨酸组成的 2个表皮生长因子 ( EGF)单体结构域 ;除了在核苷酸第 4 869位缺失 1个碱基和散在分布 5个碱基点突变之外 ,与 MAD2 0、K1和 Wellcome株相应基因之间的核苷酸同源性分别为 98.6%、2 3.3%和 2 2 .8%。结论 :本研究在世界上首次报道脑型疟患者恶性疟原虫分离株MSP1第 16— 17区 DNA序列测定分析结果 ,确证该基因与 MAD2 0株高度同源性 ,并发现在1691— 170 1位氨基酸存在 TCTEEDSGSSR表位。     

恶性疟原虫中国海南株裂殖子表面蛋白1 基因的序列分析

目的:测定恶性疟原虫中国海南分离株MSP1 基因的全序列,并进行多态性分析。方法:来自海南省保亭县2 例恶性疟患者的血样(分别滴在滤纸上)直接制备基因组DNA 后,用MSP1 基因特异的5 对寡核苷酸引物在体外扩增目的基因,用ABIPRISMTM末端标记循环测序试剂盒进行直接测序,并将测序结果与已知的等位基因型进行比较分析。结果:获得了2 个恶性疟原虫中国分离株MSP1 基因的全序列,与已知的MSP1 等位基因型进行序列比较,证实其属于MAD20 型。推导其氨基酸序列除了第2 区、第4 区和第8 区以外,其余序列完全一致。其中HN2 的第4 区含K1 型序列。结论:两株恶性疟原虫海南株的MSP1 基因属于MAD20 型,与MAD20 等位基因比较,其推导的氨基酸序列存在一些小差异。本文首次提供了恶性疟原虫中国(海南)分离株MSP1 基因多态性的依据     

恶性疟原虫中国海南株裂殖子表面蛋白1 基因的序列分析(英文)

目的:测定恶性疟原虫中国海南分离株MSP1 基因的全序列,并进行多态性分析。方法:来自海南省保亭县2 例恶性疟患者的血样(分别滴在滤纸上)直接制备基因组DNA 后,用MSP1 基因特异的5 对寡核苷酸引物在体外扩增目的基因,用ABIPRISMTM末端标记循环测序试剂盒进行直接测序,并将测序结果与已知的等位基因型进行比较分析。结果:获得了2 个恶性疟原虫中国分离株MSP1 基因的全序列,与已知的MSP1 等位基因型进行序列比较,证实其属于MAD20 型。推导其氨基酸序列除了第2 区、第4 区和第8 区以外,其余序列完全一致。其中HN2 的第4 区含K1 型序列。结论:两株恶性疟原虫海南株的MSP1 基因属于MAD20 型,与MAD20 等位基因比较,其推导的氨基酸序列存在一些小差异。本文首次提供了恶性疟原虫中国(海南)分离株MSP1 基因多态性的依据     

中缅边境恶性疟原虫裂殖子表面蛋白1,2基因多态性研究

目的对云南省及边境地区恶性疟原虫的裂殖子表面蛋白(merozoite surface protein,MSP)1,2基因进行分型研究,确定其等位基因的类型和分布特征,结合当地的恶性疟原虫株流行病学信息,为该地区疟疾的防治提供科学依据。方法从缅甸拉咱、那威和我国云南省西双版纳勐腊、德宏瑞丽、保山腾冲采集恶性疟患者血样。用巢式PCR(nest-PCR)扩增18S rRNA基因,确定感染疟原虫的种类。对检测为恶性疟原虫以及恶性疟原虫/间日疟原虫混合感染的样本,进行恶性疟原虫MSP-1、MSP-2基因的扩增并作测序、验证与序列分析。结果共采集89份恶性疟样本,经18S rRNA基因检测,确定间日疟9例,恶性疟78例和混合感染2例。在检测为恶性疟和混合感染的80份样本中,69例扩增出MSP-1基因片段,77例扩增出MSP-2基因片段。在MSP-1等位基因中,以MAD20型68.75%为主,RO33型23.75%和K1型20.00%次之。来源于勐腊的样本均未检出RO33型和K1型;MSP-2等位基因FC27型和3D7型的感染率均为91.25%,无明显的优势虫株;MSP-1和MSP-2基因多克隆样本所占百分比与多重性感染(multiplicity of infection,MOI)分别为22.50%、1.81和86.25%、3.51。MSP-1和MSP-2等位基因目的片段多样性与其原虫密度之间存在相关性(Spearman's r=0.496,P0.05;Spearman's r=0.240,P0.05)。MSP-1和MSP-2等位基因测序结果表明,在FC27型基因序列3′端发现1个新的APK序列,在3D7基因型序列中检测到1个新的PAT重复序列和其它19个新的序列。结论云南省及边境地区恶性疟原虫分离株MSP-1等位基因存在MAD20型、K1型和RO33型3种类型,以MAD20型为优势虫株,勐腊样本未发现K1型和RO33型;MSP-2等位基因存在FC27型和3D7型2种类型,其优势均不明显。     

恶性疟原虫FCC1／NH株裂殖子表面蛋白MSP1第2—5区基因的PCR扩增及克隆

构建恶性疟原虫FCC1／HN株MSP1基因2～5编码区真核表达质粒pcDNA3／MSP1，为FCC1／HN株MSP1的体外表达及其基因工程疫苗的研制奠定基础。方法采用PCR技术对恶性疟原虫海南分离株（FCC1／HN）基因组DNAMSP1第2～5区基因片段进行扩增．扩增产物经纯化后用Xhol和Aaal双酶切然后定向克隆入pcDNA3质粒，转化大肠杆菌TG1．再用相同内切酶酶切和PCR扩增对重组子进行鉴定。结果筛选出编码FCC1／HN株MSP1第2～5区基因片段的真核表达质粒pcDNA3／MSP1。结论编码FCC1／HN株MSPI第2～5区基因片段的真核表达质粒pcDNA3／MSP1的构建，为恶性疟原虫FCC1／HN株MSP1的体外表达及其基因工程疫苗的研制奠定基础。     

我国不同疟区间日疟原虫裂殖子表面蛋白1(PvMSP-1)基因多态性研究

目的　了解我国不同疟疾流行区间日疟原虫裂殖子表面蛋白 - 1基因多态性及其分布。方法　用套式PCR扩增间日疟原虫现场分离株MSP - 1第五多态区 (ICB5 -ICB6 )基因片段 ,部分样本进行序列测定、分析和比对。结果　 82份间日疟原虫现场分离株扩增出 4 70bp片段 5 0份 ,4 0 0bp片段 39份 ,其中 7份为两种片段的混合型。海南分离株混合型为 2 0 %(6 / 30 ) ,平均克隆数为 1 2 0 (36 / 30 ) ,安徽分离株混合型仅为 2 3% ,平均克隆数 1 0 2。对 33份样本进行序列测定 ,Sal- 1型17份 ,Belem型 2份 ,12份重组型 (Ⅲ型 )和朝鲜型 2份为我国新发现基因型。结论　我国间日疟原虫PvMSP - 1存在 4种不同的等位基因型 ,以Sal- 1型和重组型 (Ⅲ型 )占优势 ,南部疟区基因型比北部复杂。     

间日疟原虫MSP1 C端编码基因的克隆及序列分析

目的 克隆间日疟原虫MSP1C端编码基因,并进行序列测定和分析。方法 根据间日疟原虫MSP1C端编码基因设计1对引物,采用PCR技术从深圳间日疟患者血样(编号为PvSZ1)的核酸提取物中扩增出MSP1C端编码基因,回收纯化后,与T载体连接构建重组子pMD/MSP1,并转化大肠杆菌JM109。阳性克隆以限制性酶切分析与PCR法鉴定后,双脱氧链末端终止法双向测定序列并分析。结果 从间日疟血样提取的DNA中扩增出1119bp的基因片段,所构建的pMD/MSP1阳性克隆重组子经双酶切和PCR鉴定与预期结果一致。所测定的间日疟原虫PvSZ1C端基因序列与国外Sal-1株比较,碱基数相同,未发现碱基缺失,相同的核苷酸占96.7％,序列中第542位碱基变化为同义突变(GTC→GTT,均编码缬氨酸),第375～542区间的碱基变化数占整个序列变化碱基总数的92.9％(34/37)。所推测的氨基酸序列与Sal-1株比较,同源性为92.5％。结论 成功克隆了间日疟原虫PvSZ1株MSP1C端编码基因,该基因在不同间日疟原虫地理株间相对保守,所克隆基因序列的第375～542核苷酸区域为高频变化区。     

恶性疟原虫裂殖子表面蛋白MSP1-42基因的合成及其表达

目的 利用大肠杆菌表达系统表达可溶性的恶性疟原虫(3D7株)裂殖子表面蛋白1C末端MSP1-42蛋白.方法 采用两步PCR法拼接合成全长msp1-42基因,将测序正确的msp1-42基因构建至pET32a(+)表达载体,获得pET32amsp表达质粒,热激转化至宿主菌Rosetta gami(DE3)中进行诱导表达,用免疫印迹法检测表达产物.结果 全合成了恶性疟原虫3D7株msp1-42基因,合成基因在Rosetta gami(DE3)中以可溶性形式高水平表达,所表达的重组蛋白能与识别MSP1-19构象表位的单克隆抗体mAb5.9、PfCP2.9兔血清及恶性疟患者血清发生免疫反应.结论 合成的msp1-42基因能在大肠杆菌表达系统中以可溶性的形式表达,所表达的重组蛋白MSP1-42具有抗原性.     

恶性疟原虫海南分离株裂殖子表面蛋白2真核表达重组质粒的构建

目的 构建恶性疟原虫海南分离株（FCC1／HN）裂殖子表面蛋白2（MSP2）融合HBsAg基因片断真核表达质粒pVXORF1-PfMSP2-HBS及重组真核表达质粒pVXORF1-PfMSP2，为疟疾核酸疫苗及蛋白疫苗的研制奠定基础。方法 （1）采用PCR技术对恶性疟原虫FCC1／HN株MSP2原核表达质粒PET28α-MSP2的MSP2基因进行扩增，扩增产物经纯化后用Bam H I酶切；质粒pVXORF1-PvMSP1.19-HBS用相同的酶酶切，经纯化后用T4DNA连接酶将其与酶切后纯化的MSP2基因连接；（2）分别用BamHI Xho双酶切PET28α-MSP2质粒DNA和pVXORF1质粒DNA，纯化后2将目的基因片段用T4DNA连接酶连接；将（1），（2）连接产物分别转化大肠杆菌DH5α。于氨苄青霉素阳性LB培养平板上筛选阳性克隆，酶切电泳鉴定。结果 筛选出的重组子为编码FCC1／HN MSP2基因片段的重组质粒pVXORF1-PfMSP2-HBS及pVXORF1-PfMSP2。结论 编码FCC1／HN MSP2基因片断真核表达质粒pVXORF1-PfMSP2-HBS和pVXORF1-PfMSP2的构建为疟疾核酸疫苗及蛋白疫苗的研制奠定了基础。     

Rice‐produced MSP142 of Plasmodium falciparum elicits antibodies that inhibit parasite growth in vitro

Many malaria antigens contain multiple disulphide bonds involved in the formation of inhibitory B‐cell epitopes. Producing properly folded malaria antigens in sufficient quantities for vaccination is often a challenge. The 42‐kDa fragment of Plasmodium falciparum merozoite surface protein 1 (MSP1₄₂) is such a kind of malaria antigen. In this study, we investigated the expression of MSP1₄₂ in a rice system (9522, a cultivar of Oryza sativa ssp. japonica), which was used as a bioreactor for protein production. The MSP1₄₂ gene was synthesized according to rice‐preferred codons and transformed into rice plants via an Agrobacterium‐mediated method. The recombinant antigen was efficiently expressed in rice seeds with a level up to 1.56% of total soluble protein and was recognized by both the conformational monoclonal antibody 5.2 (mAb5.2) and the pooled sera of P. falciparum malaria patients. Rabbits were immunized intramuscularly with the purified MSP1₄₂ formulated with Freund's adjuvant. High antibody titres against MSP1₄₂ were elicited. The rabbit immune sera reacted well with the native protein of P. falciparum parasite and strongly inhibited the in vitro growth of blood‐stage P. falciparum parasites, demonstrating that transgenic rice can become an efficient bioreactor for the production of malaria vaccine antigens.     

Nest-PCR和PCR-RFLP在恶性疟原虫地理株基因分型及多态性研究中的应用

目的 分析套式PCR（nest-PCR）和限制性内切酶片段长度多态性（PCR-RFLP）方法在恶性疟原虫地理株裂殖子表面蛋白（MSP2）基因多态性研究中的分型效率及特异性。 方法 分别在海南省三亚市和云南省腾冲县等地通过静脉采血法采集疟疾患者血样98份,其中恶性疟88份,间日疟10份。另从上海地区的健康人群中抽取10份血样作为阴性对照。用nest-PCR和PCR-RFLP方法分别对疟原虫地理株进行MSP2等位基因分型,并对分型结果进行归纳和比较分析。 结果 常规nest-PCR方法对于恶性疟原虫地理株MSP2等位基因的总检出效率为79.8％（166/208）,其中,对于FC27家族等位基因的检出效率为92.7％（101/109）,但对3D7家族等位基因的检出率仅为65.7％（65/99）,且无法鉴定具体的等位基因。PCR-RFLP分型法检出效率比nest-PCR法提高了20.2%,且特异性好。 结论 PCR-RFLP相对于常规的nest-PCR分型法具有检出效率、分辨率和特异性皆高的优点,可以鉴定地理株中具体的等位基因类型。     

恶性疟原虫对氯喹抗性及其逆转剂的研究进展

恶性疟原虫对氯喹抗性的出现和广泛传播迫使人类调整治疗疟疾的用药策略并寻找更加有效的新型抗疟药。然而,在一些贫困的疟疾流行区,氯喹仍被用于治疗恶性疟。了解氯喹抗性机制、探索逆转其抗性的方法,将使氯喹这一价廉高效的抗疟药继续发挥作用。抗性逆转剂的研究和发展为上述目标提供了线索,当与氯喹合用时它能够部分恢复氯喹对氯喹抗性株的作用。为此,本文对恶性疟原虫氯喹抗性机制及其逆转剂的研究进展作一综述。     

PCR扩增环子孢子蛋白基因3’ 端片段用于检测恶性疟原虫的初步研究

目的 :建立 PCR检测恶性疟原虫的新方法。方法 :作者采用自行设计并合成的一对恶性疟原虫特异引物 ,经 PCR扩增环子孢子蛋白 ( CSP)基因 3 端保守区序列 2 4 5bp片段 ,观察了它的特异性、敏感性和稳定性。结果 :1从 4株培养的恶性疟原虫和 2例恶性疟患者血样中均扩增出约 2 4 5bp的 DNA目的片段 ,用业已鉴定的 CSP基因序列作模板再行扩增证实其为恶性疟原虫CSP基因片段 ;2对间日疟原虫、利什曼原虫、弓形虫和健康人血样进行 PCR反应 ,均未见扩增条带 ;3本检测系统可检出恶性疟原虫感染血样中 0 .18个原虫所含的 DNA模板 ;4采用不同方法制备模板及不同反应方式均能获得满意结果 ;结论 :PCR扩增恶性疟原虫 CSP基因 3端片段用于恶性疟原虫检测具有灵敏、高度特异且稳定性好等优点。     

CHARACTERISATION OF THE HOST RESPONSE TO PLASMODIUM FALCIPARUM INFECTION. I. CEREBRAL MALARIA

Abstract Cerebral malaria is a major form of complicated malaria consequent upon cerebral damage associated with endothelial cell necrosis. We have used assays of Plasmodium falciparum growth inhibition in vitro to study serum inhibitory factors in patients with cerebral malaria. Serum from children with cerebral malaria inhibited parasite growth in a non-synchronised 72-hour assay to a greater extent than did sera from immune adults or asymptomatic children (p < 0.001). The high level of non-specific inhibition of parasite growth was particularly evident when sera were tested against three P. falciparum isolates, and contrasted with the inhibitory effect of sera from non-malaria febrile controls. In this study, serum from patients with cerebral malaria was more inhibitory than serum from the other groups (p < 0.001) and its between-isolate variation, when tested against a panel of P. falciparum isolates in growth assays, was significantly less than that of the other groups tested (p < 0.005). These results are consistent with the hypothesis of toxin-induced endothelial cell damage, with the sequence of pathogenic events involving host-derived serum factors capable of damaging P. falciparum.     

Diversity and prevalence of the C-terminal region of Plasmodium falciparum merozoite surface protein 1 in China

Malaria continues to be a significant health concern for regions of southeastern Asia. Scientists have focused much effort on the development and regional testing of a vaccine against the most virulent of the pathogens that cause the disease, Plasmodium falciparum. The 19 kDa COOH-terminal region of the merozoite surface protein 1 (PfMSP1-19) is considered to be a potentially important component of a malaria vaccine and yet, to date, there is little data from China with regard to Pfmsp1-19 diversity. We have collected samples from 300 individuals diagnosed with P. falciparum infections from Yunnan and Hainan provinces - two potential vaccine trial sites in China. We determined the sequence of DNA encoding PfMSP1-19 for each. We identified seven polymorphic positions; varying arrangements of which accounted for 10 distinct Pfmsp1-19 haplotypes. Four haplotypes, however, represented more than 93% of the total. Differences in the prevalence of haplotypes between Yunnan and Hainan provinces were observed, even though the distribution of haplotypes in Yunnan province seemed to be very similar to those reported for Vietnam and Thailand. These results provide necessary information for the design of a major human vaccine trial as well as a basis for subsequent interpretations of the results. On broader scale, the data should complement the existing database on the prevalence and distribution of Pfmsp1-19 haplotypes and therefore have potential use in the design of PfMSP1-19-based polyvalent vaccines for use in Southeastern Asian countries.     

Isolation and Characterization of the MSP1 Genes from Plasmodium malariae and Plasmodium ovale

The merozoite surface protein 1 (MSP1) is the principal surface antigen of the blood stage form of the Plasmodium parasite. Antibodies recognizing MSP1 are frequently detected following Plasmodium infection, making this protein a significant component of malaria vaccines and diagnostic tests. Although the MSP1 gene sequence has been reported for Plasmodium falciparum and Plasmodium vivax, this gene has not been identified for the other two major human-infectious species, Plasmodium malariae and Plasmodium ovale. MSP1 genes from these two species were isolated from Cameroon blood donor samples. The genes are similar in size to known MSP1 genes and encode proteins with interspecies conserved domains homologous to those identified in other Plasmodium species. Sequence and phylogenetic analysis of all available Plasmodium MSP1 amino acid sequences clearly shows that the Po and Pm MSP1 sequences are truly unique within the Plasmodium genus and not simply Pf or Pv variants.     

Influence of infection on malaria‐specific antibody dynamics in a cohort exposed to intense malaria transmission in northern Uganda

The role of submicroscopic infections in modulating malaria antibody responses is poorly understood and requires longitudinal studies. A cohort of 249 children ≤5 years of age, 126 children between 6 and 10 years and 134 adults ≥20 years was recruited in an area of intense malaria transmission in Apac, Uganda and treated with artemether/lumefantrine at enrolment. Parasite carriage was determined at enrolment and after 6 and 16 weeks using microscopy and PCR. Antibody prevalence and titres to circumsporozoite protein, apical membrane antigen‐1 (AMA‐1), merozoite surface protein‐1 (MSP‐1₁₉), merozoite surface protein‐2 (MSP‐2) and Anopheles gambiae salivary gland protein 6 (gSG6) were determined by ELISA. Plasmodium falciparum infections were detected in 38·1% (194/509) of the individuals by microscopy and in 57·1% (284/493) of the individuals by PCR at enrolment. Antibody prevalence and titre against AMA‐1, MSP‐1₁₉, MSP‐2 and gSG6 were related to concurrent (sub‐)microscopic parasitaemia. Responses were stable in children who were continuously infected with malaria parasites but declined in children who were never parasitaemic during the study or were not re‐infected after treatment. These findings indicate that continued malaria infections are required to maintain antibody titres in an area of intense malaria transmission.