食蟹猴疟原虫B株配子体对大劣按纹感染性的活力周期

用食蟹猴疟原虫Ｂ株早期环状体接种１只恒河猴，接种后第２－１２天（血内仅存在１群原虫）测试了由第１－４代裂殖子形成的４代配子体（Ｇ）对大劣按蚊（海南株）感染性的活力周期。结果表明第１－４代裂殖子均形成了一定数量的Ｇ，由裂殖子发育到Ｇ功能成熟（可使蚊感染）各代有差异，第２代Ｇ至少需５５±１ｈ，第３代Ｇ则需６５±１ｈ；发育至７２±４ｈ时活力最旺，Ｇ寿命长者可达１００ｈ；生活期（对蚊有感染力的时间）第１、２代Ｇ约为１２－４２ｈ，第３代Ｇ约为１０－１９ｈ。Ｇ密度与蚊胃卵囊均数不成正比，第１、２代Ｇ对蚊的感染性比第３、４代强     

食蟹猴疟原虫B株子孢子感染后的虫血症及按蚊血餐感染情况

用食蟹猴疟原虫Ｂ株子孢子感染的６只恒河猴，初发期虫血症自然消长曲线２只猴为双峰形、４只猴为多峰形。虫血症显著期（原虫密度≥２‰）最短者为１３ｄ，最长者为３７ｄ。在虫血症显著期供１１３批（１批／日）蚊（大劣按蚊或斯氏按蚊）血餐，获得感染好的蚊虫（卵囊均数＝５－３２７．７，胃感染率＝６５－１００％）５８批、平均为９．７批。感染好的蚊批分布：双峰形的初峰期为１４．２９％（２／１４），次峰期为８５．７１％（１２／１４）；多峰形的初峰、次１和次２峰期分别为２２．７３％（１０／４４）、４５．５％（２０／４４）和３１．８２％（１４／４４）。结果提示对蚊感染性较强的血餐时间主要分布在次１和次２峰期。     

血管内皮生长因子的免疫学测定法

目的：检测肿瘤细胞条件培养液中ＶＥＧＦ的表达量。方法：在表达及分离纯化ＶＥＧＦ的基础上,成功地制备了ＶＥＧＦ抗体,以夹心法测定ＶＥＧＦ,ＶＥＧＦ测定范围为０．０２～２００．００ｎｇ／ｍｌ,灵敏度可达０．０２ｎｇ／ｍｌ,批内及批间变异均小于１０％,回收率平均为１０２．４％。其中人胃癌细胞ＭＧＣ８０３、ＢＧＣ８２３、乳癌ＮＭＣＦ－７及肝癌ＢＥＬ－７４０２分泌上清中ＶＥＧＦ的含量分别为６．５０、０．４５     

恶性疟原虫裂殖子表面蛋白1羧基端编码基因真核表达重组克隆的构建

目的构建以恶性疟原虫红内期重要的疫苗候选抗原——裂殖子表面蛋白１（ＭＳＰ１）羧基端编码分子量４２０００蛋白的基因片段为外源基因的可用作候选核酸疫苗的真核表达载体。方法目前对疟疾核酸疫苗的研究仅见于鼠疟，将恶性疟原虫ＦＵＰ株裂殖子表面蛋白１羧基端编码４２０００蛋白的基因片段用常规分子克隆方法，分别克隆入非分泌性真核表达载体ＶＲ１０１２和改建后的分泌型载体ＶＲ１０１２／ＴＰＡ中，通过ＰＣＲ和酶切鉴定出重组克隆。结果成功地构建了真核表达载体ＶＲ１０１２／ＭＳＰ１－４２和ＶＲ１０１２／ＴＰＡ／ＭＳＰ１－４２。结论目前对疟疾核酸疫苗的研究仅见于鼠疟红外期，该研究对研制有效的恶性疟原虫红内期核酸疫苗是一个有益的尝试。其免疫保护作用待进一步研究。     

中国人C4Qo表型的C4DNA限制性片段长度多态现象：静息基因的机制初探

对１７例中国人Ｃ４Ａ／Ｃ４Ｂ表型中含有Ｑ０的个体的基因组ＤＮＡ进行了ＨｉｎｄⅢＲＦＬＰ的检测。从五型Ｃ４Ａ／Ｃ４Ｂ（３，０／１，１；３；０／２．１；３．３／１．０：３．２／１．０；３．０／１．０）中共检出５种ＲＦＬＰ片段组合Ａ：３２－２５－１５ｋｂ；Ｂ：３２－１５ｋｂ；Ｃ：２５－１５ｋｂ；Ｄ：３２－１５－８．５ｋｂ；Ｅ：２５－１５－８．５ｋｂ）。根据代表Ｃ４Ａ基因缺失的８．５ｋｂ片段的有无，测出大约５０％的Ｃ４ＡＱ０是由基因缺失造成的。此外，本文还对Ｃ４ＡＱ０时Ｃ４Ｂ长、短基因的分配，Ｃ４ＢＱ０时Ｃ４基因的变动情况等进行了分析与讨论。     

食蟹猴疟原虫B株配子体对中老龄大劣按蚊的感染性

用中老龄（羽化后８．７５—１４．７５和２４．７５日龄）大劣按蚊（海南株）与其４．７５日龄蚊（对照）同时在感染Ｂ株猴疟的同一供血猴上血餐，饱血蚊饲养至第６—８ｄ解剖检查蚊胃、第１２ｄ检查涎腺。结果表明中老龄蚊胃感染率（８５—１００％）与对照（７７—１００％）无显著性差异，涎腺感染率中龄蚊（８３—１００％）与对照（７５—１００％）无显著性差异，胃与涎腺感染率比值中龄蚊（０．９２—１．０）与对照（０．９３—１．０）均很高，中老龄蚊的卵囊均数（７．３—１１５．０）为对照（５．４—８３）的１．Ｏ３—１．５８倍。结果提示Ｂ株猴疟配子体对中老龄大劣按蚊的感染性未下降。感染后的半数存活时间（ＬＴ５０），中龄蚊（１１—１５）比对照（１３—１８）少２—３ｄ。     

HIV—1gp120基因及其与IFN—α基因共表达产物的构建和 …

目的 研究细胞因子ＩＦＮ－α在机体免疫应答过程中的免疫佐剂效应。方法 以表达中国流行株ＨＩＶ－１ｇｐ１２０基因的核酸疫苗质粒ｐＧＰ及共表达中国流行株ＨＩＶ－１ｇｐ１２０基因与ＩＦＮ－α基因的核酸疫苗质粒ｐＧＰＩＦＮ－α免疫Ｂａｌｂ／ｃ鼠，用流式细胞仪测定１００００个免疫鼠脾淋巴细胞中ＣＤ４＾＋，ＣＤ８＾＋Ｔ细胞数及ＣＤ４＾＋／ＣＤ８＾＋比值。结果 ｐＧ－ＰＩＦＮ－α与ｐＧＰ比较，ｐＧＰＩＦＮ－α免     

LFA—1／ICAM—1单抗对ConA诱导脾淋巴细胞增殖及分…

通过研究ＬＦＡ－１／ＩＣＡＭ－１单抗对Ｃｏｎ Ａ诱导的脾淋巴细胞活化增殖及其分泌细胞因子的影响，探讨了ＬＦＡ－１／ＩＣＡＭ－１分子在Ｔ细胞活化过程中所起的共刺激作用。结果表明，单独应用ＬＦＡ－１α链单抗（Ｍ１７／４．４．１１．９）或ＩＣＡＭ－１单抗（ＹＮ１／１．７．４）均不能引起脾淋巴细胞的增殖，但在加入ＣｏｎＡ诱导脾淋巴细胞增殖反应的最初８小时内加入ＬＦＡ－１单抗可以剂量依赖性地抑制ＣｏｎＡ诱导     

rGM—CSF对U937细胞系膜MHC分子及CD86分子表达的作用

本实验研究了人重组ＧＭ－ＣＳＦ对Ｕ９３７人单核细胞样细胞系ＨＬＡ和ＣＤ８６分子表达的调节作用，将Ｕ９３７细胞在ｒＧＭ－ＣＳＦ１０μｇ／Ｌ培养１ｄ，ＨＬＡ－ＤＲ分子的表达率为８３％，对照组为９１％，培养ｄ表达率为５１％，对照组为７８％，培养５ｄ，表达率为５３％，对照组为８１％，Ｕ９３７细胞在ｒＧＭ－ＣＳＦ１０μｇ／Ｌ浓度下培养１ｄ，ＣＤ８６分子表达率为２％，对照组为１．６％，培养３ｄ，表达率为３．９     

羧甲基茯苓多糖对HPBL分泌IL—2,TNF,IL—6,IFN—γ的调节作用

用ＣＭＰ培养外周血淋巴细胞（ＨＰＢＬ）２４、３６、４８、７２ｈ采样检测的ＩＬ－２、ＴＮＦ、ＩＬ－６、ＩＦＮ－γ效价分别可达１３．６±４．３，４１．９±２．０，１８３７．４±４６４．３，１０３７．９±２１１．０Ｕ／ｍｌ，分别比无ＣＭＰ的细胞培养对照组的效价高０．８，７．４，０．５，１０．９倍（Ｐ＜０．０１），说明ＣＭＰ具有ＩＬ－２、ＴＮＦ、ＩＬ－６、ＩＦＮ－γ的诱生剂功能。由ＣＭＰ预处理ＨＰＢＬ后经ＰＨＡ和／或ＣｏｎＡ促诱生组的ＩＬ－２、ＴＮＦ、ＩＬ－６、ＩＦＮ－γ效价分别比无ＣＭＰ的ＰＨＡ和／或ＣｏｎＡ刺激的相应常规诱生组高１．２～２．８，０．５～１．１、０．５～０．８、０．４～０．６倍（Ｐ＜０．０１），尤以ＣＭＰ＋ＰＨＡ＋ＣｏｎＡ促诱生细胞因子效果最佳（Ｐ＜０．０１），说明ＣＭＰ又具有ＩＬ－２、ＴＮＦ、ＩＬ－６、ＩＦＮ－γ促诱生效应。     

A single-chain antibody fragment specific for the Plasmodium berghei ookinete protein Pbs21 confers transmission blockade in the mosquito midgut

Mouse monoclonal antibody 13.1 (mAb 13.1) directed against Pbs21, a 21-kDa sexual-stage surface protein of Plasmodium berghei, is known to inhibit oocyst development from gametocytes and ookinetes in the mosquito midgut. To examine the properties and potential uses of a single-chain antibody fragment (scFv) for blocking transmission of malaria parasites to mosquitoes, we have cloned and sequenced the genes encoding variable regions of the immunoglobulin heavy and light chains (V(H) and V(L)) of mAb 13.1. The V(H) and V(L) genes were assembled as an scFv gene, and expressed in a baculovirus expression system. Following purification of 13.1 scFv, Western blotting and inhibition ELISA assays confirmed that 13.1 scFv retained the binding specificity of the parent mAb 13.1 for Pbs21. Furthermore, 13.1 scFv bound to the surface of P. berghei ookinetes, and blocked oocyst development in the mosquito midgut by at least 93%, as assessed by oocyst counts in mosquitoes. We suggest that the 13.1 scFv gene could be useful not only in studying the mechanism of transmission blockade, but also in generating, by mosquito germline transformation, a model system to evaluate the production of mosquitoes refractory to malaria.     

The establishment ofPlasmodium berghei in mosquitoes of a refractory and a susceptible line ofAnopheles atroparvus

The events between the ingestion ofPlasmodium berghei-infected mouse blood and the establishment of the ookinetes in the epithelium of the midgut in refractory (R) and susceptible (S)Anopheles atroparvus are described. Simultaneously fed, fully engorged female mosquitoes were randomly assigned to dissection at 22, 28, 32, 48 h and 10 days (controls) after the infective feed (post-infection: p.i.). Serial transverse sections of 6 m were cut. Every 10th section was studied. The maturation of ookinetes was monitored at 16, 19 and 22 h p.i. The infections in R and S mosquitoes developed similarly with regard to the maturation of ookinetes and the number of mature ookinetes in the lumen of the midgut. The semiquantitative evaluation of the envelopment of the food bolus by the peritrophic layer showed that this layer cannot function as a physical barrier against migrating ookinetes. In the midgut epithelium the number of ookinetes decreased significantly with time in both R and S mosquitoes, but a similar number of penetrations was recorded for both types of mosquito. In S mosquitoes maximal 1% of the ookinetes present in the midgut formed an oocyst. In both R and S mosquitoes a substantial loss of parasites was found, first in the lumen of the midgut and second after penetration of the midgut epithelium by the mature ookinetes. Relatively few parasites develop into oocysts in S, but hardly any do so in R individuals. The factors in control of refractoriness are likely to operate on early oocyst development.     

Bacteria in midguts of field-collected Anopheles albimanus block Plasmodium vivax sporogonic development

Bacterial infections were investigated in midguts of insectary and field-collected Anopheles albimanus Weidemann from southern Mexico. Serratia marcescens, Enterobacter cloacae and Enterobacter amnigenus 2, Enterobacter sp., and Serratia sp. were isolated in field samples obtained in 1998, but only Enterobacter sp. was recovered in field samples of 1997 and no bacteria were isolated from insectary specimens. These bacteria were offered along with Plasmodium vivax infected blood to aseptic insectary An. albimanus, and the number of infected mosquitoes as well as the oocyst densities assessed after 7d. Plasmodium vivax infections in mosquitoes co-infected with En. amnigenus 2, En. cloacae, and S. marcensces were 53, 17, and 210 times, respectively, lower than in control mosquitoes, and the mean oocyst density in mosquitoes co-infected with En. cloacae was 2.5 times lower than in controls. Mortality was 13 times higher in S. marcensces-infected mosquitoes compared with controls. The overall midgut bacterial infection in mosquito field populations may influence P. vivax transmission, and could contribute to explain the annual variations in malaria incidence observed in the area.     

Characterization and immunoprotective properties of a monoclonal antibody against the major oocyst wall protein of Eimeria tenella.

The oocyst wall of Eimeria spp. consists of a 10-nm-thick outer lipid layer and a 90-mm-thick inner layer of glycoprotein which has been described previously to be composed of a single major protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions and (125)I labelling of a oocyst wall fragments and of delipidated intact oocysts revealed a molecule of approximately 12 kDa as the major protein component of the oocyst wall of Eimeria tenella. An immunoglobulin M monoclonal antibody (c11B9F3) was produced against this 12-kDa oocyst wall protein sliced from a preparative SDS-polyacrylamide gel. Its reactivity by immunofluorescence against oocyst wall fragments and sporozoites or by immunoperoxidase assays of infected tissue sections was stage restricted to gametocytes and oocysts but pan-specific against all face of the oocyst wall. In chicks passively immunized with C11B9F3, oocyst output was significantly (P<0.01) reduced by 42 to 54% after homologous E. tenella infection and by 35% after heterologous Eimeria maxima infection compared with that of control groups. The results demonstrate the presence of a highly conserved, low-molecular-weight antigen on the oocyst wall and the gametocytes of Eimeria spp. which is a candidate for inclusion in a pan-specific, transmission-blocking vaccine against avian coccidiosis.     

Induced immunity against the mosquito Anopheles stephensi (Diptera: Culicidae): effects of cell fraction antigens on survival, fecundity, and plasmodium berghei (Eucoccidiida: Plasmodiidae) transmission

Two subeellular fractions from the midgut of the malaria mosquito Anopheles stephensi (Liston) were used to immunize BALB/c mice. Mice were subsequently infected with the rodent malaria parasite Plasmodium berghei (Vineke & Lips), and the effects of anti-mosquito immunity on mosquito survival and fecundity and on parasite transmission were investigated. Mosquitoes were infected directly from mice (in vivo) or by feeding cultured ookinetes through a membrane (in vitro). Infections were monitored by counting oocysts on the midgut wall. Microvilli extracts induced a strong and partially specific antibody reaction against the midgut, which was manifest as decreased survival in in vivo fed mosquitoes and reduced fecundity in both kinds of feeding. Antisera against microvilli reduced the mean intensity of P. berghei oocysts when fed in vitro, while mosquitoes fed antiserum against basolateral plasma membranes in vivo, showed higher oocyst burdens.     

Plasmodium falciparum ookinetes migrate intercellularly throughAnopheles stephensi midgut epithelium

The migration ofPlasmodium falciparum andP. berghei ookinetes through the midgut epithelium inAnopheles stephensi was studied by transmission electron microscopy. With ruthenium red (RR) staining, the results of previous studies were confirmed:P. falciparum ookinetes take an intercellular route through the midgut epithelium. In the same mosquito species, the rodent parasiteP. berghei appeared to take an intracellular position, as previously suggested by other authors. The intra- or intercellular ookinete migration ofP. berghei orP. falciparum, respectively, can perhaps be related to the higher mortality ofP. berghei-infected mosquitoes within the first 2 days of infection. Evidence is presented that oocyst capsule formation begins as early as during the migration of the ookinete. After localization between the epithelial cells and the midgut basal lamina, the rapidly expanding oocyst stretches the overlying layer of the latter at the haemocoelic surface while a new basal lamina is generated between the oocyst and epithelial cell.Abbreviations BL basal lamina - CR cristalloid - N nucleus - RER rough endoplasmic reticulum - Mp malarial pigment - M mitochondrion - MV microvillous border - OC oocyst capsule     

Immunity against sexual stage Plasmodium falciparum and Plasmodium vivax parasites

The efficient spread of malaria from infected humans to mosquitoes is a major challenge for malaria elimination initiatives. Gametocytes are the only Plasmodium life stage infectious to mosquitoes. Here, we summarize evidence for naturally acquired anti-gametocyte immunity and the current state of transmission blocking vaccines (TBV). Although gametocytes are intra-erythrocytic when present in infected humans, developing Plasmodium falciparum gametocytes may express proteins on the surface of red blood cells that elicit immune responses in naturally exposed individuals. This immune response may reduce the burden of circulating gametocytes. For both P. falciparum and Plasmodium vivax, there is a solid evidence that antibodies against antigens present on the gametocyte surface, when co-ingested with gametocytes, can influence transmission to mosquitoes. Transmission reducing immunity, reducing the burden of infection in mosquitoes, is a well-acknowledged but poorly quantified phenomenon that forms the basis for the development of TBV. Transmission enhancing immunity, increasing the likelihood or intensity of transmission to mosquitoes, is more speculative in nature but is convincingly demonstrated for P. vivax. With the increased interest in malaria elimination, TBV and monoclonal antibodies have moved to the center stage of malaria vaccine development. Methodologies to prioritize and evaluate products are urgently needed.     

Induction of Plasmodium falciparum transmission-blocking antibodies in nonhuman primates by a combination of DNA and protein immunizations

Malaria transmission-blocking vaccination can effectively reduce and/or eliminate transmission of parasites from the human host to the mosquito vector. The immunity achieved by inducing an antibody response to surface antigens of male and female gametes and parasite stages in the mosquito. Our laboratory has developed DNA vaccine constructs, based on Pfs25 (a Plasmodium falciparum surface protein of 25 kDa), that induce a transmission-blocking immune response in mice (C. A. Lobo, R. Dhar, and N. Kumar, Infect. Immun. 67:1688-1693, 1999). To evaluate the safety, immunogenicity, and efficacy of the Pfs25 DNA vaccine in nonhuman primates, we immunized rhesus macaques (Macaca mulatta) with a DNA vaccine plasmid encoding Pfs25 or a Pfg27-Pfs25 hybrid or with the plasmid (empty plasmid) alone. Immunization with four doses of these DNA vaccine constructs elicited antibody titers that were high but nonetheless unable to reduce the parasite's infectivity in membrane feeding assays. Further boosting of the antibody response with recombinant Pfs25 formulated in Montanide ISA-720 increased antibody titers (30-fold) and significantly blocked transmission of P. falciparum gametocytes to Anopheles mosquitoes (~90% reduction in oocyst numbers in the midgut). Our data show that a DNA prime-protein boost regimen holds promise for achieving transmission-blocking immunity in areas where malaria is endemic and could be effective in eradicating malaria in isolated areas where the level of malaria endemicity is low.     

我国首次分离巴泰病毒的分子生物学鉴定

目的对从云南蚊虫中分离的YN924病毒进行分子生物学鉴定,从分子生物学水平明确其分类地位。方法扩增YN924病毒的S片段并测序,通过ClustalX(1.8)、Phylip、Treeview(3.2)软件对S片段的序列进行分析,并构建种系发生树;对S片段编码产物N蛋白及NSs蛋白的氨基酸顺序进行分析。结果用两对引物均可从YN924病毒扩增出产物,序列分析发现S片段与巴泰病毒(X73464)的同源性最高,为96.4%;N蛋白、NSs蛋白的氨基酸顺序与巴泰病毒的同源性分别为99.1%和98%。结论从云南分离的YN924病毒属于巴泰病毒,我国首次对该病毒进行分子生物学鉴定。