免疫层析试验与镜检法、聚合酶链反应诊断疟疾的比较

目的　评价免疫层析试验 (ICT)诊断疟疾的临床应用价值。方法　以镜检法和聚合酶链反应 (PCR)为对照 ,同时用ICT检测 89份门诊可疑疟疾感染患者的血标本。结果　ICT与镜检法和PCR比较 ,阳性检出符合率分别为 93 .4 %和 86.4 % ;敏感性分别为 90 .16%和 83 .3 3 % ;特异性分别为92 .86%和 91.3 0 %。当虫体密度 >10 0个 / μl时 ,ICT的敏感性为 10 0 % ,虫体密度 <10 0个 / μl时 ,敏感性为 72 .73 % ,虫体密度 <5 0个 / μl时 ,敏感性降低到 66.67%。 结论　ICT适用于疟疾检测的初筛 ,但尚不能完全替代镜检法     

云南省边境地区疟疾防治资源分配分析

目的 分析云南省边境地区疟疾资源分配状况与疟疾传播的关系，为合理分配疟疾资源提供依据。方法 收集中老、中缅、中越边境地区有关疟疾统计资料，研究导致疟疾流行的危险因素。结果 结果表明来自国外和国内的波及效应数值和强度效应综合反映了这些边境县所面临的潜在疟疾传播危险因素。结论 该地区的疟疾防治资源分配不合理，有待进一步改善。     

Entomological survey and report of a knockdown resistance mutation in the malaria vector Anopheles gambiae from the Republic of Guinea

The purpose of our entomological survey was to estimate mosquito biodiversity, infectivity rates and insecticide resistance levels in Anopheles species in four study sites in a mining area with high malaria transmission in southeastern Guinea. Anopheles gambiae s.l. (77%) was the most common Anopheles collected followed by An. funestus (20%). The specimens of the An. gambiae complex were predominantly An. gambiae S form (97.6%) with 1.4% of An. gambiae M form found in Kérouané only, and 1% of An. arabiensis which was present in all four study sites. Anopheles gambiae S form and An. funestus were found to be infected with Plasmodium falciparum, with infectivity rates of 4.1% and 4.4% and inoculation rates of 0.60 and 0.19 infected bite/person/night, respectively. In addition, a high level (79%) of the knockdown resistance (kdr) L1014F mutation was reported in the populations of An. gambiae S form. The high malaria transmission that occurs in the prospected area of Guinea requires a long-term vector control programme. However, such a control programme will have to consider the presence of the kdr gene at a surprisingly high level within the dominant vector, which could reduce the expected impact of vector control.     

2001年广西疟疾防治效果及流行特征分析

目的：分析2001年全区疟疾防治效果、流行趋势、流行特征，为疟疾防治与监测提供依据。方法：对全区2001年疟疾监测结果和调查结果资料进行分析研究。结果：2001年全区疟疾发病率、居民原虫阳性率分别比上年降低21．74％及16．67％，91．49％的当地感染的病人分布在山区县，86．02％的病灶村为1例病人。流动人口检出疟疾病例数占各类人群血检检出疟疾病例总数的87．89％，外出回归人员检出病例中84．79％的病人从事与野外作业相关的工种。结论：全区大部分地区为低疟区，局部地区疟疾传播仍未阻断。流动人口和山区复媒地区是当前疟疾监测的重点。     

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.     

Induction of a cytotoxic T cell response by co-injection of a T helper peptide and a cytotoxic T lymphocyte peptide in incomplete Freund's adjuvant (IFA): Further enhancement by pre-injection of IFA alone

We have previously demonstrated that it is possible to induce a consistent and strong cytolytic T lymphocyte (CTL) response to synthetic peptides, corresponding to poorly immunogenic malaria CTL epitopes, by co-injecting them with peptides representing defined T helper (Th) epitopes in incomplete Freund's adjuvant (IFA). In this study we have tested different immunization protocols to improve further the elicitation of the CTL response. We show that the CTL response to a mixture of Th + CTL peptides administered in IFA was further enhanced by a previous injection of the Th epitope peptide in IFA. Moreover, we found that the response could be significantly augmented by a pre-injection of IFA alone. This enhancement was observed only if the Th epitope was also present in the second injection. The number of lymph node cells recovered was 2–3-fold higher in mice pre-injected with IFA, but the increase in specific CTL activity, expressed as lytic units per animal, by pre-injection of IFA was at least 10–20-fold. Thus, pre-injection of IFA clearly increases the magnitude of a subsequent CTL response.     

Identification of parasite proteins in a membrane preparation enriched for the surface membrane of erythrocytes infected with Plasmodium knowlesi

A subcellular fraction enriched in erythrocyte membranes has been isolated from rhesus monkey erythrocytes infected with Plasmodium knowlesi. Infected cells were lysed by centrifugation through a zone of hypotonic buffer and membranes isolated by equilibrium density gradient centrifugation in the same tube. The purified membrane fraction was shown to include the erythrocyte surface membrane by several methods: electron microscopy, identification of Coomassie Blue stained erythrocyte membrane proteins, identification of band 3 with a monoclonal antibody, and identification of radioiodinated cell surface proteins. The resulting ghosts were shown to be specifically reactive with monkey sera against the variant surface antigens of P. knowlesi by indirect immunofluorescence and membrane agglutination. No reactivity was seen with a monoclonal antibody (13C11) against the intracellular schizont surface. A number of metabolically labelled parasite proteins were enriched in this membrane function, including peptides of 277, 208, 173, 153, 134, 109, 80, 60 and 48 kDa and the variant surface antigens of variable molecular mass (180-207 kDa). These proteins were distinct from the major parasite proteins of total infected erythrocytes and isolated merozoites. The major glucosamine labelled glycoprotein of the internal schizont (230 kDa) was not found in this fraction. Moreover, no fragment of this parasite glycoprotein was found in this membrane fraction, indicating that no part of this molecule is transported to the erythrocyte surface. In contrast, the variant antigen of P. knowlesi, known to be on the erythrocyte surface, could be readily identified as peptides unique to specific cloned parasite lines. We propose that the other nine parasite proteins found within this membrane fraction represent a starting point for the identification of other parasite proteins transported to the surface membrane of the infected erythrocyte.     

CD1d-restricted NKT cells contribute to malarial splenomegaly and enhance parasite-specific antibody responses

CD1d-restricted NKT cells are a novel T cell lineage with unusual features. They co-express some NK cell receptors and recognize glycolipid antigens through an invariant T cell receptor (TCR) in the context of CD1d molecules. Upon activation through the TCR, NKT cells produce large amounts of IFN-gamma and IL-4. It has been proposed that rapid cytokine output by activated NKT cells may induce bystander activation of other lymphoid lineages. The impact of CD1d-restricted NKT cell activation in the induction of B cell-mediated immune responses to infection is still unclear. We show here that CD1-restricted NKT cells contribute to malarial splenomegaly associated with expansion of the splenic B cell pool and enhance parasite-specific antibody formation in response to Plasmodium berghei infection. The increased B cell-mediated response correlates with the ability of NKT cells to promote Th2 immune responses. Additionally, antibody responses against the glycosylphosphatidylinositol (GPI)-anchored protein merozoite surface protein 1 (MSP-1) were found to be significantly lower in CD1(-/-) mice compared to wild-type animals. P. berghei-infected MHC class II (MHCII)(-/-) mice also generated antibodies against MSP-1, suggesting that antibody production against GPI-anchored antigens in response to malaria infection can arise from both MHCII-dependent and independent pathways.     

Increased fluidity of Plasmodium berghei-infected mouse red blood cell membranes detected by electron spin resonance spectroscopy

The fluidity of Plasmodium berghei-infected mouse red cell membranes is increased over that of uninfected cells at both 24°C and 37°C. This was demonstrated by electron spin resonance spectroscopy using the hydrocarbon spin labels 2-dodecyl-2′,5,5′-trimethyloxazolidine-N-oxyl and 2-heptyl-2′ -hexyl-5,5′-dimethyloxazolidine-N-oxyl to label regions of the bilayer near its surface, and deeper within the hydrocarbon region, respectively. Arrhenius plots of the ‘empirical motion parameter’ (R_i) obtained from 2-heptyl-2′-hexyl-5,5′-dimethyloxazolidine-N-oxyl-labeled cells versus temperature over the range from 0 to 45°C showed an hysteretic behavior of the spin labels in the membranes of both mature and immature uninfected cells. Such hysteretic behavior was consistently lacking in membranes of infected cells. These differences in membrane fluidity and spin label behavior are interpreted to reflect biochemical modifications of the red cell membrane which occur with infection by the malarial parasite.