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1.
The present study exhibits original results of S. mansoni tegumental alterations due to contact with the immune system of non anti-helminthic treated mice. We compared, by SEM, the tegument of adult worms recovered from strains of mice genetically selected to extreme phenotypes of resistance (TR strain) and susceptibility (TS strain) to egg-albumin oral tolerance (OT). The parasites recovered from TR mice displayed no morphologic alteration, while specimens collected from TS mice presented tubercle swelling with blunted and shortened spines in lower density, increased sensory organelle numbers, fusion and tegumental ridge peeling. These tegument alterations were similar to those described for Artemether or Praziquantel treatment, supporting observations that the host immune system influences the development and function of the tegument of worms harbored in both anti-helminthic treated and non-treated mice. Our results are indicative that the development and function of the worm tegument depend on the immune regulatory capacity of each individual host.  相似文献   

2.
The surface of the schistosomula is an important target for host immune system attack because the tegument represents the interface between host and parasite and thus is a potential candidate for the development of new intervention strategies. In this study, we evaluated the ability of schistosomula tegument (Smteg) to induce protection in mice. Immunization of mice with Smteg together with Freund adjuvant induced a Th1 type of immune response associated with a significant reduction in worm burden (43-48%), eggs trapped in the liver (65%), eggs eliminated in the faeces (59-60%) and granuloma number (41%). Lastly, during an in vitro study, worms from mice immunized with Smteg showed damage in the adult worm tegument and impaired egg laying.  相似文献   

3.
Alterations in the tegument of 21-day-old Schistosoma mansoni, caused by artemether administered to the infected mice, were studied using scanning electron microscopy (SEM). Mice were infected with S. mansoni cercariae, and after 21 days a single dose of artemether (400 mg/kg) was administered intragastrically. After 24, 72 h and 7 days groups of three mice were killed and the schistosomules collected by perfusion, fixed and processed routinely, and examined by SEM. After 24 h, all male and female worms examined showed alterations in the tegument, characterised by swelling, vesiculation and fusion of tegumental ridges; peeling, erosion and collapse of damaged tegumental surface, and also destruction of the oral sucker and acetabulum. After 72 h, severe damage to the tegument was seen, usually including extensive peeling, swelling and vesiculation, and host leukocytes were adhered to the damaged surface. Some worms were surrounded by clusters of host leukocytes or had even disintegrated. Seven days after treatment, some schistosomules still showed severe tegumental damage, but in some cases the damage was less than at earlier times, which suggested that those schistosomules that had survived were beginning to recover. The ability of artemether to cause severe damage to the tegument correlates with its high efficacy in killing 21-day-old schistosomules.  相似文献   

4.
目的 观察蒿甲醚对小鼠体内埃及血吸虫成虫超微结构的损害。 方法 8只小鼠于感染埃及血吸虫尾蚴后81 d用单剂蒿甲醚400 mg/kg口服治疗。治后24 h、3 d、7 d和14 d各剖杀2只小鼠,用灌注法收集血吸虫,并按常规方法固定和处置虫体,作透射电镜观察。从另2只未治疗的感染小鼠体内取虫作对照。 结果 蒿甲醚对血吸虫皮层超微结构的损害主要是皮层基质的肿胀、溶解和空泡变化,基底膜消失和部份受损皮层破裂;在感觉器和皮层结节中,常见其内部结构广泛溶解。在肌层、实质组织、合体细胞和肠管上皮细胞中,查见局灶性或广泛的溶解、粗面内质网减少及线粒体空泡变化和变性。雌虫卵黄细胞的严重变化是空泡变化、粗面内质网减少、卵黄球融合以及受损卵黄细胞破溃等。上述雌、雄虫变化于感染小鼠用蒿甲醚治疗后24 h即可见到,并逐渐加重,3~7 d后最重。治后14 d,部分雌、雄虫仍示有超微结构的损害,但同时亦观察到受损虫组织的恢复。 结论 蒿甲醚对埃及血吸虫成虫的皮层和皮层下组织具有广泛和严重的超微结构损害。  相似文献   

5.
目的 评价蒿甲醚对小鼠体内埃及血吸虫皮层的损害作用。 方法 8只小鼠于感染埃及血吸虫尾蚴后81 d,用单剂蒿甲醚400 mg/kg口服治疗。治疗后1、3、7和14 d各剖杀2只小鼠,用灌注法收集血吸虫,并按常规方法固定和处置虫体,作扫描电镜观察。从另2只未作治疗的感染小鼠取虫作对照。 结果 用蒿甲醚治疗后24 h,雄虫的皮层结节肿大、破溃或从皮层上剥落; 在雄虫和雌虫的体表可查见有局灶性或广泛的皮层肿胀、融合、空泡变化、糜烂和剥落,以及感觉结构的破坏。治疗后3 d,雌、雄虫的皮层损害加重,最严重的损害为口吸盘肿胀和破溃,并查见皮层褶嵴有广泛和严重的肿胀、糜烂和剥落,以及雌虫盘状感觉结构的破坏。治疗后7至14 d,有些虫仍示有中或重度皮层损害,而有些仍存活的虫则示其大部分皮层已有明显恢复。 结论 蒿甲醚对埃及血吸虫的皮层具有广泛和严重的损害作用。  相似文献   

6.
The interaction of the mouse complement system with adult male Schistosoma mansoni was studied by immunocytochemical localization procedures and in-vitro assays for complement mediated tegument damage. Mouse C3 was demonstrated to be associated with the parasite's tegument, but was localized only in the infoldings of the tegument and not on its free surface. Freshly harvested parasites manifested no detectable tegumental modification when incubated in normal mouse serum or in immune mouse serum. However, parasites which had been allowed to lose their adsorbed host components by elution (incubation in serum free media for 3 h at 37 degrees C) were severely damaged by incubation in normal mouse serum, but not by incubation in immune mouse serum. This damage was shown to be mediated by the alternative complement pathway and appeared to be initially limited to the tubercles of the adult male parasite. Tegument disruption could be blocked by pre-incubation of the eluted worms in either immune mouse serum or an IgG fraction of immune mouse serum. An IgG fraction of normal mouse serum did not protect the parasite, and infected mouse serum (IMS) which had been depleted of IgG produced tegument damage equivalent to that observed with normal mouse serum (NMS). The addition of I-IgG to NMS abrogated tegument damage. These data suggest that while adult schistosomes possess surface molecules bearing alternative pathway complement activation sites, these sites are masked by adsorbed host components in vivo. These results further indicate that in the absence of these masking host molecules anti-schistosome IgG may play a role in protecting the adult worm from alternative pathway activation, perhaps by binding to and blocking the activation sites on the tegument associated molecules.  相似文献   

7.
The tegumental membranes of adult Schistosoma mansoni have been isolated and purified and shown to function as potent immunogens; they elicit an essentially identical immune response in rabbits, rats and mice. Anti-membrane antisera harvested from these animals consistently recognized common antigens, of relative molecular weight (mol. wt) 32 000 and 20 000, on the surface of young schistosomula, 5 day old lung worms and adult worm purified membranes. An additional molecule of 25 000 mol. wt was present on the surface of lung worms and adult worm membranes and was specifically recognised by serum from chronically infected mice and by serum from rabbits inoculated with adult worm purified membranes. The concept of antigenic identity between developmental stages that parasitize the mammalian host was further substantiated by the observation that anti-membrane antiserum bound to live schistosomula, lung worms and adult parasites as measured by indirect immunofluorescence. In complement-mediated in vitro cytotoxicity assays, the sera from rabbits inoculated with either adult worm purified membranes, or the 32 000 mol. wt antigen partially purified from adult worm membranes, mediated levels of schistosomula killing as high as those obtained with sera from chronically infected mice. These rabbit antisera also promoted eosinophil adherence and killing of newly transformed schistosomula, but lung stage parasites, despite binding the anti-membrane antiserum, were refractory to both humoral and cellular cytotoxicity. The significance of antigenic identity is discussed in relation to the concept of concomitant immunity.  相似文献   

8.
Hybridization experiments between the two non-sibling species of schistosomes, Schistosoma mekongi in man and S. japonicum-like (Malaysian) in rodents, were carried out. Two laboratory-bred snail species, Tricula aperta (beta race), the snail host of S. mekongi and Robertsiella kaporensis, the snail host of S. japonicum-like (Malaysian), were used for the production of cercariae. Cross mating between S. mekongi and S. japonicum-like (Malaysian) were achieved in the laboratory by the usual procedure of exposing snails to single miracidia of each species, then exposing mice to cercariae emanating from two snails only, each infected with a different species. Hybrid eggs and miracidia were used to infect snails of both species. The resultant F1 cercariae were used to infect mice. It was shown in this study that the attempt to cross these two species of schistosomes could be achieved in the laboratory, but the results provided very low yield of hybrid worms and eggs. F1 hybrid adult worms from S. mekongi male and S. japonicum-like (Malaysian) female were obtained and examined for the microtopography of the tegument by scanning electron microscopy. The tegumental surface of the hybrid male schistosome resembled the male parent, S. mekongi, with a few characters which resembled the male, S. japonicum-like (Malaysian). The surface tegument of the hybrid male worm was characterized by the presence of highly-branched and perforated ridges interspersed with a large number of papillae all over the body surface with the heaviest concentration on the middle portion of the body. There were four types of papillae present; the pleomorphic papillae; the cratered papillae, with or without cilia; the hemispherical sensory papillae with cilia; and the fungiform papillae. Spines were absent on the body surface except in the oral and ventral suckers and in the gynecophoral canal. The tegument lining the gynecophoral canal was characterized by the presence of low ridges with scattered papillae with small number of short spines in the posterior portion of the canal. In contrast to the male, the female hybrid worm had numerous spines all over the body surface with the most concentration in the posterior region. Among the spines were low perforated ridges. Two types of papillae were present in the female hybrid; the cratered papillae, with or without cilia, and the hemispherical papillae.  相似文献   

9.
目的:通过东方田鼠(Microtus fortis,Mf)感染日本血吸虫(Schistosoma japonicum,Sj)后肺和肝的组织细胞反应以及虫体受损情况,探寻Mf体内杀伤Sj的效应细胞和Sj的受损原因。方法:以Sj尾蚴经腹部皮肤感染Mf5d和11d后剖杀,分别取肺和肝,固定,切片,光镜下观察虫全周围的组织细胞反应,并与同时期的感染小鼠组织切片进行比较,同时,对Mf体内的Sj童虫进行扫描电镜观察。结果:Mf肺脏虫体周围有一定量的嗜酸性粒细胞浸润,而肝脏虫体周围有大量的嗜酸性粒细胞和少量的中性粒细胞,巨噬细胞等浸润,同时期的感染小鼠组织内虫体周围炎症反应不明显,电镜观察显示Mf体内的Sj存在明显的畸形和发育延迟,结论:嗜酸性粒细胞可能是Mf体内杀伤Sj的重要效应细胞,Sj在Mf体内不能正常发育。  相似文献   

10.
Aiming to study the influence of long-term administration of lipid lowering agents (atorvastatin; AV), and to study the action of combined treatment with injectable contraceptive (medroxyprogesterone acetate; MPA) on tegumental ultrastrucutre and survival of Schistosoma worms, this study was established. AV (0.9 mg kg-1) was administered orally for 49 successive days to Schistosoma heamatobium-infected hamster starting from day 35 post-infection (pi). Another group of infected hamster was administrated MPA intramuscularly (0.1 ml kg-1) at days 7 and 35 pi followed by AV treatment regimen. Both treatment regimens significantly affected the surface ultrastructure of the male worms more pronouncedly than the female ones. Combined treatment was more severe in action compared to single one. The combined treatment was characterized by losing of spines and damaging of tubercles throughout the tegument, severe erosion and peeling and appearance of deep crakes in different parts of the tegument. Moreover, mild to sever destruction to the oral suckers of both female and male worms was noticed. On the other hand, both treatment regimens significantly reduced numbers of recovered S. haematobium worms and tissue egg load. Oogram pattern was affected only in case of combined treatment with high percentage of dead eggs. In conclusion, AV, if given continuously for long time, has a pronounced antischistosomal action especially when accompanied with contraceptive intake. These promising results may encourage further investigation with the intention of their possible application on treatment of schistosomiasis as a complement strategy to praziquantel chemotherapy.  相似文献   

11.
Mouse infection models are described that demonstrate reduction in the rate of egg production in Schistosoma haematobium worms 6–10 weeks after the onset of oviposition and loss of Schistosoma bovis worms around 10 weeks after infection. Neither phenomenon has been shown in Schistosoma mansoni- or Schistosoma japonicum-infected mice. The immunological basis for these anti-adult responses was inferred by comparison with infections in T-cell deprived mice and by transferance of the ability to reduce a S. bovis worm burden in immuno-compromised hosts with immune serum. Vaccination with irradiation-attenuated parasites of S. haematobium was also shown to have consequences for the adults of challenge infections of either S. haematobium or of S. bovis, but not of S. mansoni. Thus, prior vaccination resulted in an abrogation of the reduced egg production by S. haematobium and S. bovis worms and also of the adult worm elimination that occurred in non-vaccinated S. bovis-infected mice. These models are being used to define the targets and mechanisms involved in the attrition of adult worms of schistosomes with terminal spined eggs.  相似文献   

12.
目的实验观察日本血吸虫吡喹酮抗性株在终宿主小鼠体内的生物学特性,探索日本血吸虫吡喹酮抗性株对终宿主的致病力及传播强度。方法分别采用日本血吸虫江苏吡喹酮敏感株和抗性株、湖南吡喹酮敏感株和抗性株尾蚴定量感染小鼠,建立小鼠-钉螺-小鼠生活史循环,观察比较各虫株的虫卵开放前期、产卵量及虫卵分布、对终宿主的易感性、虫体生长发育等生物学特性。结果日本血吸虫江苏吡喹酮敏感株和抗性株虫卵开放前期分别为36.1 d和36.8d(t=0.907,P=0.372),粪便中虫卵数分别为14.6只/100 mg和21.2只/100 mg(t=2.946,P=0.007),回收成虫数分别为20.5条/鼠和25.1条/鼠(t=2.128,P=0.042),组织中虫卵数分别为31 303只/对成虫和38 594只/对成虫(t=2.185,P=0.040)、肝脏虫卵数分别为14 810只/对成虫和19 715只/对成虫(t=2.934,P=0.007),肠组织中虫卵数分别为16 493只/对成虫和18 879只/对成虫(t=1.044,P=0.309);江苏敏感株和抗性株雌雄合抱虫体长度(t=0.328,P=0.744)、雌虫体长(t=0.386,P=0.701)及雄虫体长(t=0.332,P=0.741)差异均无统计学意义。日本血吸虫湖南吡喹酮敏感株和抗性株虫卵开放前期分别为35.5 d和35.6 d(t=0.169,P=0.867),粪便中虫卵数分别为13.3只/100 mg和18.9只/100 mg(t=3.622,P=0.001),回收成虫数分别为17.6条/鼠和25.1条/鼠(t=3.153,P=0.004),组织中虫卵数分别为30 932只/对成虫和53 903只/对成虫(t=3.865,P=0.001),肝脏虫卵数分别为12 307只/对成虫和26 363只/对成虫(t=4.388,P0.01),肠组织中虫卵数分别为18 625个/对成虫和27 541个/对成虫(t=2.679,P=0.012);湖南敏感株和抗性株雌雄合抱虫体长度(t=0.853,P=0.397)、雌虫体长(t=0.573,P=0.569)及雄虫体长(t=0.742,P=0.461)差异均无统计学意义。结论日本血吸虫吡喹酮抗性株产卵量和肝组织虫卵沉积量均明显高于敏感株,提示其对终宿主的致病性更强;抗性株感染鼠粪便中排出虫卵数明显多于敏感株,提示抗性株的传播能量高于敏感株。  相似文献   

13.
The tegumental surfaces of adult male and female of Schistosoma spindale were studied by scanning electron microscopy. In general, the body surface of the male appears to be fairly uniform from anterior end to posterior end. It is characterized by the presence of transverse ridges and papillae of various types. These papillae are distributed fairly regularly over the whole body surface of the worm. The tegument lining the gynecophoral canal of the male worm is covered with numerous spines interspersed with papillae, some without cilia and some with crater-like holes in the centres and apical cilia. The tegument of the female worm is covered with smooth and perforated ridges and sensory bulbs with apical nodules.  相似文献   

14.
目的观察青蒿琥酯(Art)对体外培养的卫氏并殖吸虫童虫与成虫的杀虫效果。方法卫氏并殖吸虫童虫及成虫用含不同浓度Art的的RPMI1640培养基体外培养后作光镜与电镜观察。结果0.25mg/mL组体外培养24h后,虫体萎缩,扫描电镜观察部分体棘消失、倒伏、絮状物附着;透射电镜显示皮层水肿、细胞器及分泌颗粒减少,卵黄腺萎缩,卵巢卵细胞胞浆空泡变等。结论青蒿琥酯对卫氏并殖吸虫童虫及成虫有损伤作用。  相似文献   

15.
目的 应用感染曼氏血吸虫 (利比里亚株 )的小鼠观察蒿甲醚单剂量与效应的关系,虫体肝移及蒿甲醚所引起的虫的形态学和组织病理学变化。 方法 感染21d童虫的小鼠一次口服蒿甲醚12.5mg/kg至600mg/kg不同剂量 ,治后28d剖检观察各组虫数。感染46d或70d成虫的小鼠一次口服蒿甲醚40 0mg/kg后8~14d ,观察虫体肝移及其形态和组织病理学变化。 结果 蒿甲醚对21d童虫的最低有效剂量为200mg/kg ,减虫率为 81%。用蒿甲醚治疗后8h成虫开始肝移,3~7d全部肝移,14d有31%的虫返回肠系膜静脉。成虫虫体萎缩,咽部扩大,肠管膨胀及其色素减少。雌虫局部体表受损,白细胞附着,卵巢及卵黄腺变性退化,以及雄虫睾丸萎缩等。在肝内的虫体被嗜酸粒细胞为主的炎细胞包围和浸润。 结论 蒿甲醚对小鼠曼氏血吸虫21d童虫的最低有效剂量为200mg/kg ,可引起曼氏血吸虫成虫萎缩、退化或死亡。在肝内受损的虫体主要是被嗜酸粒细胞包围和侵袭所致。  相似文献   

16.
青海不同株细粒棘球绦虫成虫的超微结构研究   总被引:2,自引:2,他引:2  
王虎 《地方病通报》1997,12(2):9-12
运用透射电镜和扫描电镜分别观察了青岛海高原牦牛和藏羊源原头蚴感染犬后细粒棘球绦虫成虫的超微结构。结果表明两源细粒棘球绦虫成虫的表面结构和皮层结构相似。这些形态结构特点与文献报道明显不同,提示青海高原存在不同株的细粒棘球绦虫。  相似文献   

17.
The maturation of female Schistosoma japonicum was found to vary greatly within each of two Philippine strains of this parasite and some females did not contain uterine eggs 7 to 15 weeks after infection while others contained numerous eggs before the fifth week of infection. It was found that female worms containing less than 20 uterine eggs contributed little to the accumulation of eggs in the tissues of infected mice. Such worms also generally appeared to be immature. The variable rate of maturation of worms is likely to have profound effects on the immune reactions of mice as well as on the pathologic response to infection. Systematic delay in oviposition was serendipitously found in worms from mice which had been irradiated for other purposes prior to exposure to S. japonicum, and from the fourth to the sixth week after infection egg production by worms in irradiated mice lagged well behind that in intact mice. Seven to 10 weeks after infection these worms were laying normal numbers of eggs, as judged by egg passage per worm pair in the feces and the accumulation of eggs in the tissues. S. mansoni developed normally in irradiated mice.  相似文献   

18.
目的:探讨环孢素A体外抗曼氏血吸虫的作用。方法:MF1小鼠实验感染曼氏血吸虫6wk后,经主动脉和门静脉灌注收虫。将雄虫放入含有1μg/ml、10μg/ml、15μg/ml、20μg/ml和25μg/ml环孢素A的199培养液中体外培养。用扫描电镜对药物所致的虫体皮层损害作时间生物学观察。结果:在体外,雄虫经1μg/ml环孢素A作用后,体嵴的结构疏松;经10μg/ml环孢素A作用24h后,雄虫皮层肿胀;雄虫经15μg/ml环孢素A作用8h-24h后,虫体皮层破溃;虫体经20μg/ml药物作用24h后,雄虫皮层明显破溃;雄虫经25μg/ml环孢素A作用8h后,皮层褶嵴受损;作用16h后,皮层肿胀;作用24h后,皮层极度破溃,皮棘脱落。药物所致的虫体皮层损害与剂量和时间呈依赖关系。结论:环孢素A具有直接杀曼氏血吸虫的作用。  相似文献   

19.
目的通过观察日本血吸虫(Schistosoma japonicum,Sj)紫外线辐照致弱尾蚴感染小鼠后肺组织的细胞反应以及肺期虫体的受损情况,探寻致弱尾蚴在小鼠体内诱导免疫效应机制和Sj受损情况。方法以紫外线致弱Sj尾蚴经腹部皮肤感染小鼠4d、7d、14d和45d后剖杀,分别取肺组织,固定、切片,光镜下观察虫体周围的组织细胞反应,并与同时期的感染小鼠组织切片进行比较,同时,对小鼠体内肺期Sj童虫进行扫描电镜观察。结果感染后4~7d,小鼠肺期童虫虫体周围出现较明显的出血灶和炎症反应,并有一定量的嗜酸性粒细胞、中性粒细胞、巨噬细胞等炎症细胞的浸润,同时期的正常感染小鼠组织内虫体周围炎症反应却不明显;虫体体壁可见不同程度的损伤,电镜观察显示小鼠体内的肺期童虫存在明显的畸形和发育延迟。结论紫外线辐照致弱尾蚴感染后Sj在小鼠体内不能正常发育成熟,和正常尾蚴相比,致弱尾蚴在肺期滞留时间较长,仅有极少数虫体可移行至肠系膜或肝脏,但宜不能发育成熟,引起的病理损害主要表现为在肺期弥漫性出血灶、炎症细胞浸润等反应,这些特征可能与血吸虫致弱尾蚴感染免疫机制有关。  相似文献   

20.
Rabbit antisera were raised against an antigen present in Schistosoma mansoni adult worms and eggs, and were shown to yield a single immunoprecipitin arc in immunoelectrophoresis and immunodiffusion against S. mansoni egg and worm antigen extracts. The antisera conferred partial but significant protection (22–30%) against a S.  mansoni challenge when transferred to mice five and six days after the mice had been infected percutaneously with 200 cercariae. The egg and the worm forms of the antigen were immunologically cross-reactive, but the egg antigen possessed peptidolytic activity that could be inhibited with serine protease inhibitors. In indirect immunofluorescence the rabbit antisera reacted with surfaces of cercariae, five-day old lung-stage schistosomula, miracidia and praziquantel-treated adult worms. Gel-filtration chromatography demonstrated a relative molecular size of approximately 480 kDa for both the egg and worm forms of the antigen, and lectin-affinity chromatography indicated both were glycosylated. The serine protease activity and large relative molecular size of egg Sm480 were confirmed by a combination of radiolabelling with tritiated di-isopropyl fluorophosphate, immunoelectrophoresis and polyacrylamide gel electrophoresis.  相似文献   

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