旋毛虫、卫氏并殖吸虫及华支睾吸虫之间共同抗原的研究

目的鉴定旋毛虫、卫氏并殖吸虫及华支睾吸虫之间的共同抗原,避免血清学诊断这3种寄生虫病时的交叉反应。方法应用十二烷基硫酸钠-聚丙烯酸胺凝胶电泳(SDS-PAGE)和免疫印渍(Western blot)对旋毛虫肌幼虫、卫氏并殖吸虫成虫及华支睾吸虫成虫可溶性抗原中的蛋白组分进行研究。结果旋毛虫肌幼虫、卫氏并殖吸虫成虫及华文睾吸虫成虫3者相同蛋白带的分子量为108、65、53、43、42、31、25、16 kDa。免疫印渍结果表明,旋毛虫和卫氏并殖吸虫抗原中分子量为 65、58、53kDa的蛋白带均与旋毛虫感染的大鼠、小鼠及患者血清、肺吸虫感染的大鼠和患者血清发生反应;旋毛虫和华支睾吸虫抗原中分子量为108kDa的蛋白带均与旋毛虫感染的大鼠、小鼠及患者血清、肝吸虫病患者血清发生反应;而3种可溶性抗原中的53kDa与本实验中所有寄生虫感染的动物和患者均有交叉反应。结论 65、58、53 kDa蛋白为旋毛虫和卫氏并殖吸虫的共同抗原,108kDa蛋白为旋毛虫和华支睾吸虫的共同抗原,而53 kDa蛋白为这3种寄生虫的共同抗原。     

旋毛虫幼虫侵入小鼠肠上皮细胞后细胞蛋白变化的研究

目的观察旋毛虫幼虫侵入前后小鼠肠上皮细胞蛋白的变化，筛选幼虫侵入相关蛋白。方法将旋毛虫感染性幼虫接种至小鼠小肠上皮细胞（intestinal epithelial cells，IECs）单层，于37℃5％CO2条件下培养2h，提取细胞蛋白，进行SDS-PAGE与Western blot分析，并与正常IECs细胞蛋白比较。结果SDS-PAGE分析表明，IECs与感染性幼虫共孵育后的IECs蛋白带数为44条，与正常IECs对照组的相同；Western blot显示，正常IECs蛋白不能被旋毛虫感染鼠血清识别，与幼虫共孵育后的IECs蛋白有16个组分带能被旋毛虫感染鼠血清识别，分子质量单位分别为125、118、106、98、70、64、50、47、46、40、34、33、31、29、27、26ku。结论小鼠IECs与旋毛虫幼虫共培养可产生能被旋毛虫感染鼠血清识别的细胞蛋白，该组蛋白可能是旋毛虫侵入相关蛋白。     

Interaction of mannan-binding lectin with Trichinella spiralis glycoproteins, a possible innate immune mechanism

Complex and variable glycoconjugates presented by parasitic nematodes during infection are very important in the host-parasite interplay. Predominantly carbohydrate-rich antigens are involved in the stimulation and modulation of the stage-specific immune response of the host. The non-specific innate immune system, however, acts as the first line of host defence against pathogens, before the appearance of antigen-specific responses. The functional entities of the innate system are lectins that recognize the surface ligands of pathogens: mannan-binding lectin (MBL) is a key recognition element involved in binding oligosaccharide structures exposed on microorganisms. In the present study we investigated whether MBL binds to the parasitic nematode Trichinella spiralis (T. spiralis). Since the parasite is coated with mannose-containing glycans, these structures could represent potential ligands for MBL and contribute to activation of the innate immune response of the host. Histochemical staining revealed MBL on the surface and internal organs of T. spiralis muscle larvae. MBL bound in a mannose-inhibitable manner to both crude extracts of T. spiralis muscle larvae and larvae excretory/secretory products. Western blot analyses showed that MBL recognized glycoproteins from all stages of T. spiralis. In vitro complement activation assays suggested that MBL is capable of fixing complement components on T. spiralis crude extract coated plates and activating the complement cascade through the 'lectin pathway'.     

Regulation of the growth and differentiation of Trypanosoma (Trypanozoon) brucei brucei in resistant (C57B1/6) and susceptible (C3H/He) mice

While Trypanosoma brucei brucei GUTat 3 were equally infective for C3H/He and for C57Bl/6 mice at doses ranging from 5 to 5 x 10(3) organisms and had similar prepatent periods in both strains of mice, infected C57Bl/6 mice displayed lower parasitaemia, shorter times to parasite wave remission and survived for a longer time than infected C3H/He mice. Parasite growth and differentiation rates and host immune responses were similar for the first 5 days in both strains of mice after infection with 10(3) T.b.brucei GUTat 3 but, thereafter, parasite differentiation proceeded more rapidly and specific antibodies reached higher titres in C57Bl/6 than in C3H/He mice. In contrast, parasite growth and differentiation rates were similar in irradiated mice of both strains. Furthermore, following inoculation of intact mice with irradiated T.b.brucei GUTat 3, C3H/He mice actually mounted higher titred antibody responses than C57Bl/6 mice showing that they were not intrinsically defective in their capacity to respond to GUTat 3 antigens. Parasite differentiation occurred at the same rate in irradiated (650r) C57Bl/6 mice and in irradiated C57Bl/6 mice reconstituted with syngeneic spleen cells although T.b.brucei GUTat 3 specific antibody was detected in the latter mice prior to peak parasitaemia. Furthermore, it was shown directly in C57Bl/6 mice that there was no selective destruction of slender form T.b.brucei GUTat 3 parasites during the phase of accumulation of stumpy form parasites. These studies indicate that the more rapid differentiation of T.b.brucei GUTat 3 parasites in infected C57Bl/6 mice as compared to infected C3H/He mice was unlikely to be directly related to the more efficient antibody response in the infected C57Bl/6 mice. The observations suggest that there might be an association between host mechanisms which regulate differentiation of T.b.brucei parasites and those which regulate antibody responses.     

旋毛虫肌幼虫特异性抗原的鉴定

目的 寻找诊断旋毛虫病的特异性抗原。方法 应用SDS—PAGE和Western blot对旋毛虫肌幼虫可溶性抗原中的蛋白组分进行研究。结果 旋毛虫肌幼虫可溶性抗原经SDS—PAGE后显示29条蛋白带，分子量范围在112—12kDa之间，其中65、43、42、31、30、20、17、16kDa为主带。112、110、108、102、97、95、65、63、58、55、53、49、45、43、42kDa蛋白组分与并殖吸虫感染的大鼠及患者血清、华支睾吸虫病、血吸虫病及囊尾蚴病患者血清均具有明显的交叉反应带；24—20kDa蛋白组分只与旋毛虫感染的大鼠、小鼠及患者血清反应，而不与其它寄生虫感染的动物或患者血清、正常大鼠和小鼠及正常人血清发生交叉反应。结论旋毛虫肌幼虫可溶性抗原中24—20kDa蛋白组分为旋毛虫肌幼虫的特异性抗原，可用于旋毛虫病的免疫学诊断及血清流行病学调杏。     

Influence of free radicals on Trichinella spiralis infection in mice

The aim of the study was to examine the influence of free radicals: nitric oxide (NO), hydrogen peroxide (H202) and superoxide anion (O2-) on Trichinella spiralis infection in mice. The studies were performed on two strains of mice: C57BL/6 and BALB/c, which differ in immunological response to T. spiralis infection. Also the influence of AG--inhibitor of inducible nitric oxide synthase (iNOS) administered in the first days after T. spiralis infection (1-5 dpi) on the cytotoxic immune response and on the number of adult parasites as well as the influence of AG administered at the beginning of muscle phase of the T. spiralis infection (16-29 dpi) on the cytotoxic immune response and the number of muscle larvae was studied. Activation of macrophages can cause pathology. Contact of macrophages with antigens stimulates these cells to produce, among others, highly reactive inorganic compounds. There are free radicals: NO, H2O2 and O2-. NO, O2-, and their metabolites are highly toxic for most pathogens, including parasites. However, little is known about their role in the defense against T. spiralis infection. The performed studies have proved, that free radicals play role in the host immune response during both intestinal and muscle phase of T. spiralis infection in mice. In the intestinal phase of the T. spiralis infection cytotoxic immune response is activated in mice peritoneal cavity and in the muscle phase, the local immune response activated in the neighborhood of larvae in muscles appeared as the higher level of free radicals in blood and urine. Administration of AG between 1-5 dpi causes opposite reactions in two different strains of mice. In BALB/c mice AG causes fast expulsion of adult T. spiralis from the intestine but in C57BL/6 mice the expulsion of parasites is slower after AG. However, there are no differences between two strains of mice after treatment with AG between 16 and 29 dpi. AG causes diminution of larvae in muscles of both BALB/c and C57BL/6 mice. Inflammatory response in peritoneal cavity is observed later during the infection in "low responders" (C57BL/6) mice in comparison with "high responders" (BALB/c) mice. Thl like mice (C57BL/6) react stronger to AG treatment than Th2 like mice (BALB/c). It occurs as changes and fluctuations in free radicals levels and the number of peritoneal cells after AG treatment in C57BL/6 mice.Weak or no reaction on AG injections in BALB/c mice is responsible for more stabile and more sufficient defense response of the host to T. spiralis infection.     

Secretion of IL-12 by murine macrophages activated by immunoglobulin receptor-mediated internalization of the surface coat of Trichinella spiralis larvae

Trichinella spiralis larvae incubated with a rabbit antiserum raised against the larval surface coat bound murine macrophages to the parasite surface. Cell binding was not observed without the antisurface coat serum, or with incubation of larvae in normal rabbit serum, or with antibodies to keyhole limpet haemocyanin which identify a cryptic T. spiralis larval antigen. Cell adherence to the larval surface was lost by treatment of the cells with the lysosomotropic drug primaquine, implicating a receptor-mediated mechanism. Cells adhering to the parasite surface internalized parasite surface coat material, which was subsequently concentrated into endosomes. Culture supernatants from these cells contained enhanced levels of IL-12. Thus, the initial Th1 response to T. spiralis infection may be explained by these data.     

免疫层析试纸条诊断旋毛虫病的研究

目的建立一种能诊断人体旋毛虫病及动物旋毛虫感染的快速血清学方法。方法以胶体金标SPA和旋毛虫肌幼虫ES抗原制备免疫层析试纸条(immunochromatographic strip),对旋毛虫病及其它寄生虫病患者血清、旋毛虫及其它寄生虫感染的动物血清进行检测。结果试纸条检测旋毛虫病患者与旋毛虫感染的小鼠、大鼠、兔、猪血清的阳性率分别为100%(20/20)、97.87%(92/94)、100%(5/5)、100%(5/5)及100%(25/25),15min内肉眼可观察结果;其它寄生虫病(并殖吸虫病、血吸虫病、华支睾吸虫病、囊虫病及包虫病等)患者及正常人血清、其它寄生虫感染动物及正常动物血清均为阴性。试纸条和ELISA对100条幼虫感染小鼠血清检测的阳性率分别为91.3%(21/23)和95.7%(22/23)(χ2=0.36,P>0.05),两种方法对200～500条幼虫感染小鼠血清检测的阳性率均为100%(71/71)。试纸条对乡土旋毛虫、布氏旋毛虫、伪旋毛虫及纳氏旋毛虫感染小鼠血清检测的阳性率亦均为100%。试纸条在4℃可保存13个月,检测结果在室温可保存3个月。结论该试纸条可用于人体旋毛虫病和动物旋毛虫感染的快速血清学诊断,也可用于其它种旋毛虫感染的血清流行病学调查。     

两种新型免疫佐剂CT-B、Saponin制备的旋毛虫疫苗对小鼠免疫保护作用的比较研究

目的　比较两种新型免疫佐剂CT -B(霍乱毒素B亚单位 )、saponin(皂素 )制备的旋毛虫疫苗对小鼠的免疫保护作用。方法　将旋毛虫肌幼虫可溶性抗原分别与CT -B、saponin混合 ,以口服或皮下注射途径免疫NIH小鼠 ,间隔 1周共免疫 3次 ,末次免疫后 1周 ,与对照组同时予 2 0 0条旋毛虫感染期肌幼虫攻击 ,比较三组小鼠肠道成虫数、雌虫生殖力及肌幼虫数。结果　与对照组比较 ,CT -B组成虫减虫率、新生幼虫减虫率及肌幼虫减虫率分别为 91 5 9%、6 1 74 %和 90 32 % ,saponin组成虫减虫率、新生幼虫减虫率及肌幼虫减虫率分别为 79 2 1%、6 7 4 4 %和 88 39%。 结论　CT -B和saponin均能有效提高机体对旋毛虫的保护性免疫力 ,CT -B对肠道成虫的影响更显著     

Failure of mebendazole in the treatment of humans with Trichinella spiralis infection at the stage of encapsulating larvae.

Trichinella spiralis larvae infective for laboratory mice were collected from muscle biopsies performed at different times (from 1 day to 16 months) following the end of treatment, indicating the failure of mebendazole to kill Trichinella parasites when they are encapsulating in muscles.     

旋毛虫成虫可溶性抗原和排泄分泌抗原对小鼠免疫保护作用的比较研究

目的　比较旋毛虫成虫可溶性抗原和排泄分泌抗原对小鼠的免疫保护作用。方法　收集人工感染大鼠小肠内的成虫, 经研磨和冻融制备成虫可溶性抗原。采用体外培养的方法从培养液中提取旋毛虫成虫排泄分泌抗原。分别用两种抗原免疫小鼠, 间隔１ 周共免疫３ 次, 末次免疫后１ 周, 每只小鼠攻击感染１００ 条旋毛虫感染性肌肉幼虫。感染后１ 周检查小鼠小肠内成虫数量和雌虫生殖力, 感染后５ 周检查肌肉幼虫负荷。结果　成虫可溶性抗原诱导的成虫减虫率、新生幼虫减虫率和肌肉幼虫减虫率分别为７９５５ ％ 、６２２５ ％ 和６５０ ％ 。成虫排泄分泌抗原诱导的成虫减虫率、新生幼虫减虫率和肌肉幼虫减虫率分别是９７２７ ％ 、８６６０ ％ 和９００ ％ 。结论　实验结果表明旋毛虫成虫可溶性抗原和成虫排泄分泌抗原均能够诱导宿主产生较强的抗攻击感染的免疫力, 但后者的免疫原性更强。     

Species-specific and common epitopes on the secreted and surface antigens of Toxocara cati and Toxocara canis infective larvae

It is widely accepted that the major cause of visceral larva migrans (VLM) in man is Toxocara canis infection. This has been largely based on the detection of antibodies to this species. We have compared the antigens of T. canis and Toxocara cati in order to establish whether assay for the former might be compromised by infection with the latter. Comparisons were made by radioiodination of the surface and excretory/secretory (ES) glycoproteins of the infective larvae of both species, immunoprecipitation with poly- and monoclonal reagents, and SDS-PAGE. The SDS-PAGE profiles of surface antigens of the two species showed few similarities, whereas that of the ES material indicated considerable homology. Serum from infected animals and a human VLM patient exhibited complete cross reactivity, although there was evidence in the mouse of a specific response to one of the components of T. cati ES. Testing of ES against a panel of monoclonal antibodies (MoAbs) confirmed the similarity; all but one of the MoAbs recognized several of the components of both sources of ES. The only exception was MoAb Tcn-2, which did not react with T. cati surface, somatic or ES antigens. This antibody is known to recognize a carbohydrate determinant which is widespread on T. canis glycoproteins. This species-specific determinant, therefore, represents a reversal of the consensus that peptide determinants tend to be the more specific. Finally, the MoAbs were used to examine the exposure of shared epitopes on the surface of intact larvae of T. cati. Again, fine differences in binding by anti-carbohydrate monoclonals were observed when the two species of Toxocara were compared, reflecting a distinction in exposure or orientation of surface molecules on these nematodes. Moreover, these epitopes were absent or variably present on the surface of freshly hatched larvae, and full exposure did not occur until about 24 h post-hatching. This delay in the presentation of epitopes might have implications for the process of infection in sensitized hosts. In conclusion, it is probable that the serological response in man to T. canis is, by current serological methods, indistinguishable in specificity from that induced by T. cati infection, and that the MoAb which we describe could be used to permit discrimination.     

Comparative ultrastructural studies of the alterations to mouse lung parenchyma during Trichinella spiralis or Toxocara canis infection

Trichinella spiralis and Toxocara canis larvae migrated through the lung and induced many alterations in the lung parenchyma. Using electron microscopy, we identified and described the histopathological changes. These changes resulted from mechanical damage or from local inflammatory reactions provoked by larvae. The pattern of changes was described between 6 and 12 days post‐infection (DPI) with T. spiralis larvae, and between 21 and 28 DPI with T. canis. The ultrastructural studies demonstrated that T. spiralis larvae migrating through the lungs evoked mainly destruction of type I epithelial cells, destruction of lamellar bodies of epithelial cells or extracellular alveolar lining layer. The severity of these changes was dependent on the number of infective larvae (400 or 800 T. spiralis larvae) and possibly the result of mechanical damage in the lung parenchyma. In contrast, infection with T. canis larvae initiated mainly eosinophilic perivasculitis and vasculitis as well as macrophage accumulation in the lung, which were additionally impacted by numerous crystalloid inclusions in macrophages. Trichinella spiralis larvae and T. canis larvae induced different pathological changes in the lungs of infected mice.     

Changes in the immune response of BALB/c mice coinfected with Heligmosomoides polygyrus and Trichinella spiralis

The influence of Heligmosomoides polygyrus on infection with Trichinella spiralis was studied in BALB/c mice. Mice coinfected with T. spiralis and previously given H. polygyrus harboured both nematode species till day 34. The number of T. spiralis muscle larvae was greater in mice coinfected with H. polygyrus/T. spiralis or T. spiralis/H. polygyrus than after infection with T. spiralis alone. Infection with H. polygyrus did not enhance eosinophil and IL-5 levels induced by T. spiralis. Additionally, the production of IgG1 specific to L1 T. spiralis was inhibited by co-infection. Changes in the levels of IFN-gamma and IgG2a implicated a disturbance in Th2 cell activation during protective response and resulted in the greater number of T. spiralis muscle larvae in coinfected mice.     

Surface associated glycoproteins from Toxocara canis larval parasites

The surface of infective larvae of Toxocara canis, the dog ascarid nematode, reveals relatively few exposed surface proteins which can be recovered in soluble form. The major components identified by surface labelling have molecular weights of 32, 55, 70 and 120 kilodaltons (kDa), and are all significantly glycosylated. All are recognised by the immune response in definitive (canine) and paratenic (murine or human) hosts. Expression of these antigens on the parasite surface begins after the larvae hatch from infective ova in vitro, and presumably in vivo. Each of these molecules may also be found in the set of secreted (ES) glycoconjugates released by larval parasites cultivated in vitro, and currently available biochemical and functional data on the surface/secreted ES glycoproteins are presented. Analysis with monoclonal antibodies (MAbs) confirms the identity of surface and ES molecules, and these MAbs show differing patterns of binding to the epicuticle, the cuticular matrix and to the oral orifice. Alternative mechanisms for antigen synthesis, insertion into the cuticle and export from the parasite are discussed.     

旋毛虫肌幼虫排泄分泌物中特异性诊断抗原的研究

目的　寻找旋毛虫肌幼虫排泄分泌(ES)物中的特异性诊断抗原。　方法　应用SDSPAGE和Western印迹对旋毛虫肌幼虫体外培养18、30h后的ES抗原中的蛋白组分进行研究。　结果　旋毛虫肌幼虫培养18、30h后得到的ES抗原组分大致相同,两种ES抗原中主要蛋白带的分子量为112、110、108、97、53、49、45、42、35、23和16kDa。18hES抗原中的102、97、95和53kDa以及30hES抗原中的53、49、45和43kDa均与并殖吸虫病、华支睾吸虫病、日本血吸虫病及囊尾蚴病患者血清发生明显的交叉反应。ES抗原中的23kDa蛋白组分只与旋毛虫感染的大鼠、小鼠及患者血清反应,而不与上述其它寄生虫感染者、正常大鼠和小鼠及正常人血清发生交叉反应。　结论　旋毛虫肌幼虫ES抗原中的23kDa蛋白组分为旋毛虫肌幼虫的特异性抗原,可用于旋毛虫病的血清学诊断及血清流行病学调查。     

Protection against Trichinella spiralis induced by a monoclonal antibody that promotes killing of newborn larvae by granulocytes

Summary Mouse monoclonal antibodies directed against biochemically defined surface antigens of Trichinella spiralis were selected and tested for their ability to destroy parasites in vivo and in vitro. One of these (NIM-M5; IgGl), which recognised a surface component of approximately 64 K molecular weight in newborn larvae (NBL), bound to a surface component of this stage (as shown by fluorescence), and mediated the adherence of rodent eosinophil leucocytes to the surface of living NBL. Following cell adherence mediated by this monoclonal antibody, the worms were killed. This effect was enhanced by fresh normal serum suggesting a role for complement in this phenomenon. A monoclonal antibody directed against a surface component of infective larvae (NIM-M1; IgM) did not promote adherence of cells nor killing of NBL in vitro. The effect of NIM-M5 on the development of NBL to the intramuscular stage was examined. Treatment of NBL with the NIM-M5 monoclonal antibody prior to their injection into mice, together with passive transfer of NIM-M5 for 3 days, significantly reduced (36–51%) the proportion of larvae recovered by digestion 28 days later. Thus a single monoclonal antibody to NBL was able to mediate eosinophil-dependent destruction of worms in vitro and reduce infectivity in vivo. These observations suggest that antibodies capable of mediating eosinophil-induced destruction of nematodes in vitro may also be important in protection against infection.     

Lymphocyte, antibody and cytokine responses during concurrent infections between helminths that selectively promote T-helper-1 or T-helper-2 activity

The injuence of Trichinella spiralis on infections with Trichuris murk was studied in non-responder B10. BR mice. Mice infectedonly with T. muris were unable to expel parasites and had many adult worms 35 days later. Infection with 300 larvae of T. spiralis, given seven or 14 (but not 28) days after T. muris, enabled mice to expel up to 90% of T. muris; expulsion of T. spiralis was not altered. Concurrently infected mice produced less T. murisspecijic IgG2a antibody than mice infected with T. muris only, andshowed higher proliferative responses when spleen and mesenteric lymph node cells were cultured in vitro with T. murk antigens. When T. spiralis was present mucosal mast cells were generated in T. muris-infected mice, whereas almost no mast cells were seen with only T. muris. Lymphocytes from doubly-infected mice produced significantly more interleukin 4 and 5 (IL-4, IL-5) and significantly less interferon-gamma (IFN-y) when stimulated in vitro with Concanavalin A (Con-A) than cells from mice infected with T. murk only. These data demonstrate that BI0.BR mice, which in single infections produce a Thl response to T. muris and develop no protective immunity, can mount a protective T-helper-2 (Th2) response and expel T. murk when concurrently infected with the ‘Th2 inducing’ nematode T. spiralis.     

Heterogeneity in the expression of surface-exposed epitopes among larvae of Ascaris lumbricoides

Quantitative immunofluorescence was used to examine differences in the binding of antibody to the surfaces of individual living infective stage larvae of Ascaris lumbricoides. Using rabbit antisera, it was first established that larvae cultured for 48 h after artificial hatching were relatively uniform in their levels of antibody binding and in minimal exposure of epitopes expressed by later larval stages. Aliquots from a pool of larvae were probed with serum from individual infected people living in an endemic area of Nigeria. The larvae used were derived from parasites collected in the same geographical area in which serum donors were living. Two principal points emerged. First, serum donors varied considerably in the degree to which their antibody bound to the larvae. Secondly, the binding of antibody from a given donor revealed remarkable heterogeneity in surface epitope expression. Such intra-specific variability in antigen expression has considerable implications for the development of immunity to parasitic nematodes.     

旋毛虫成虫可溶性粗抗原对小鼠的免疫保护作用

本文应用人工感染的方法从大白鼠获得大量成虫。经冻融、超声粉碎、高速离心制备出成虫可溶性粗抗原。将不同剂量的抗原与等体积弗氏完全佐剂乳化后间隔1周共免疫小白鼠3次。最后一次免疫后间隔1周每鼠攻击感染130条感染性肌幼虫,攻击感染后1周剖检成虫、新生幼虫,攻击感染后35天剖检肌幼虫。试验结果表明,以每只小白鼠免疫200μg成虫可溶性粗抗原所诱导的免疫力最好,诱导成虫减虫率达94.65％,肌幼虫减虫率达95.60％。初步研究表明,旋毛虫成虫可溶性抗原是很好的免疫原。