A single gene copy merozoite surface antigen and immune evasion?

During the course of chronic malaria infection antigenic variants of a parasite antigen are expressed and exposed on the surface of infected erythrocyte membranes. There also exists a number of apparently invariant single gene copy blood-stage antigens, exposed or non-exposed, which have been shown to afford immunity under experimental conditions. To determine why the host, presented with invariant 'protective' antigens, is unable to control infections effectively, immunity to a representative single gene copy antigen, the merozoite surface protein 1 (MSP1) was investigated in Plasmodium chabaudi chabaudi AS, a murine model of chronic malaria. Immunization with monoclonal antibody affinity purified native MSP1 resulted in enhanced control of parasitaemia on challenge, irrespective of the parasite inoculum size; challenge with a single parasite, however, suggested that expansion of resistant parasite subpopulations was not occurring. Challenge of mice immunized with recombinant fusion proteins encoding N- or C-terminal regions of the P.c. chabaudi AS MSP1 produced inconsistent effects, often parasitaemias were indistingishable from controls despite significant anti-MSP1 antibody responses. The not unlikely contamination of MSP1 native preparations with erythrocyte (E) components was considered. Immunization with a mixture of the MSP1 C-terminus recombinant polypeptide and a Triton X-100 solubilized lysate of normal E resulted in enhanced control of parasitaemia, however, no effect was seen after administration of either component on its own. Co-immunization of E with the N-terminus polypeptide reversed the inhibition seen, on this occasion with this construct alone.     

Secondary processing of the Plasmodium falciparum merozoite surface protein-1 (MSP1) by a calcium-dependent membrane-bound serine protease: shedding of MSP133 as a noncovalently associated complex with other fragments of the MSP1

Merozoites of the malaria parasite Plasmodium falciparum possess on their surface proteolytically processed fragments of the merozoite surface protein-1 (MSP1). Secondary processing of one of these fragments, MSP1₄₂, always occurs prior to, or at the point of successful erythrocyte reinvasion. It is shown that a product of this secondary processing, MSP1₃₃, is shed in the form of a noncovalently-associated complex with a number of other proteins, including the MSP1-derived species MSP1₃₈ and MSP1₈₃. Secondary processing of MSP1₄₂, is inhibited by the chelating agents ethylenediaminetetraacetic acid (EDTA) and ethyleneglycol-bis-(β-aminoethyl ether)-tetraacetic acid (EGTA), and this inhibition is reversible by addition of excess calcium. Secondary processing occurs in preparations of washed, disrupted merozoites, and is inhibited by the protease inhibitors phenylmethylsulphonyl fluoride (PMSF) and diisopropyl fluorophosphate (DFP), indicating that the protease responsible is a membrane-associated serine protease.     

硬膜外脊髓电刺激仪的研制

临床实验证实硬脊膜外脊髓电刺激(ESCS)与减重步态疗法(PWBT)相结合,能明显提高患者脊髓损伤康复后的行走能力,对运动能量代谢产生显著影响,但相应的神经与生理机制目前尚不清楚.本研究开发研制一种小型低功耗的先进ESCS刺激仪,为ESCS机理的实验研究提供所需的刺激模式.基于印刷电路板工艺,采用聚酰亚胺对银电极触点进行绝缘封装,改进电极的设计.进行ESCS刺激仪性能的动物实验验证,改变电压幅值、频率和波宽等刺激参数,观察实验猫肌肉的抽搐情况.实验结果表明:所研制的小型低功耗ESCS刺激器能提供所需的多通道多模式刺激信号,电池供电和低功耗设计可提供使用安全性,ESCS电极满足柔韧性和生物兼容性要求,可为ESCS和PWBT组合疗法的机理研究提供先进实验手段.     

大肠癌p16抑癌基因甲基化及与Dukes分期的关系

目的 检测大肠癌患者p16基因启动子CpG区甲基化的改变,探讨其与大肠癌发生、发展和临床资料的关系。方法 采用甲基化特异PCR技术（MSP法）研究58例大肠癌标本p16基因甲基化改变,分析临床病理资料。结果 25例标本（43．1％）呈p16 CpG区甲基化阳性;Dukes C、D期病人p16 CpG区甲基化发生率（75％）明显高于Dukes A、B期病人（13．3％）。结论 p16启动子区甲基化导致p16抑癌基因失活参与了大肠癌的发生和发展;p16甲基化可以作为估计大肠癌病人预后的一个指标。     

Human phase I vaccine trials of 3 recombinant asexual stage malaria antigens with Montanide ISA720 adjuvant

Two phase I vaccine trials were conducted to test the immunogenicity and safety of a vaccine containing three recombinant malaria antigens from the asexual stage of Plasmodium falciparum. The three antigens are a fragment of MSP1 (190LCS.T3); MSP2 and a portion of RESA and were formulated in Montanide ISA720 adjuvant. These trials investigated the dose response of each antigen for eliciting both antibody and T-cell responses and the immunogenicity of a mixture of the antigens compared with the antigens injected separately. All three antigens elicited both antibody and T-cell responses. Strong T-cell responses were observed with 190LCS.T3 and RESA with stimulation indices exceeding 100 for peripheral blood leucocytes in some individuals. The antibody responses were generally weak. The human antibody responses observed with MSP2 in Montanide ISA720 were not significantly different from those obtained in an earlier trial which used MSP2 with alum as the adjuvant. No antigenic competition was observed: volunteers receiving a mixture of antigens had similar responses to those receiving the three antigens at separate sites. Tenderness and pain at the injection site were common over the first few days following immunization. In some volunteers, especially those receiving the highest doses tested, there was a delayed reaction at the injection site with pain and swelling occurring approximately 10 days after injection.     

慢性淋巴细胞性白血病患者miR-9-3甲基化异常及其意义

目的本研究旨在探讨microRNA-9-3(miR-9-3)在慢性淋巴细胞性白血病骨髓细胞中的甲基化异常及其意义。方法采用甲基化特异性聚合酶链反应(MSP)技术检测8例正常骨髓组织、78例新确诊的慢性淋巴细胞性白血病患者和7种白血病细胞株甲基化水平。结果正常对照组miR-9-3呈未甲基化状态;7种白血病细胞株中有5种呈未甲基化状态(71.4%);78例慢性淋巴细胞性白血病患者中65例呈miR-9-3甲基化,MSP阳性率为83%。5-氮杂-2'-脱氧胞苷(5-Aza Dc)处理白血病细胞株后I83-E95和WAC3CD5+细胞株miR-9-3呈未甲基化状态。结论慢性淋巴细胞性白血病患者存在miR-9-3表达受抑,可能与其基因甲基化异常有关。而miR-9-3甲基化在激活慢性淋巴细胞性白血病患者NF-κB1信号通路的作用值得进一步研究。     

基于MSP430F149单片机的心电信号数据采集系统的设计与研究

目的设计一种低成本的便携式心电信号数据采集系统，实现长时间对心电信号进行采集与存储。方法对采集的心电信号进行放大、滤波、电平提升和模数转换后存储于Flash存储器，再通过液晶显示器显示实时心电波形。结果本系统可实现对心电信号进行长时间的数据采集和记录。结论本系统对于临床和患者应用都具有一定的实用价值。     

Differential antibody recognition of FC27-like Plasmodium falciparum merozoite surface protein MSP2 antigens which lack 12 amino acid repeats

Three alleles of the FC27-type allelic family of the MSP2 gene of the malaria parasite Plasmodium falciparum have been sequenced from parasites from the field (The Gambia and Tanzania). These alleles lack the 12 amino acid repeat units which are usual in this family of MSP2 alleles. We have investigated the recognition by sera from an endemic area (The Gambia) of three recombinant MSP2 proteins that have 5, 1 and no copies of this repeat region. Antibody recognition of these recombinant proteins varied according to the number of repeats present. High titre antibody levels were seen with most sera using the recombinant protein with 5 × 12-mer repeats, whereas only low responses were measured using proteins containing 1 or no 12-mer repeats. Several sera entirely failed to recognise the protein which lacked 12-mer repeats. The data suggest that variation in the number of tandem repeat sequences could allow the parasite to avoid high avidity antibody binding and this may allow escape from immune recognition.     

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MAD20 株裂殖子表面蛋白1 (MSP1) 和FC27 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EcoRI 和KpnI, BamHI 和HindIII 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 JM 103 扩增, 用碱裂解法抽提重组子复制型DNA (RFDNA ) 后, 再分别经EcoRI 和KpnI, BamHI 和HindIII 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MAD20 株MSP1 和FC27 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。