Influence of cadmium on the course of intestinal and muscular phases in mice infected with Trichinella spiralis]

At the first experiment 20 Swiss male mice were infected with 100 larvae and 20 mice with 500 larvae T. spiralis per mouse. Two days after infection (d.a.i.) mice orally received 1.5 mg Cd (water solution CdCl2) each. 40 mice were infected only T. spiralis as control. At the second experiment muscle larvae used were isolated from mice (from the first experiment) which received Cd. 20 mice were infected with 100 larvae and 20-with 500 larvae per mouse. Two d.a.i. mice received 1.5 mg Cd. Mice from both experiments were killed at 5, 10, 20 and 42 d.a.i. Total number of adult T. spiralis worms present in the small intestine and muscle larvae were recovered by conventional technique. Results of the first experiment: the number of adult worms and muscle larvae recovered from mice received Cd. were statistically significant lower as in control. Results of the second experiment: the mean number of adult worms in experimental group and in control were the same but the mean number of larvae per gram of mice muscle were significant higher as in control.     

Interleukin-5 deficient mice exhibit impaired host defence against challenge Trichinella spiralis infections

Enteric nematode infections are characterized by both peripheral and tissue eosinophilia. The cytokine interleukin (IL)-5 is considered a critical factor in the proliferation and recruitment of eosinophils, however, studies suggest it plays little role in host defence, at least during primary Trichinella spiralis infections. Less is known concerning its role in host defence or in the inflammatory response that develops against challenge infections with the same parasite. We examined these questions by infecting IL-5 deficient and wild-type mice, with T. spiralis parasites. Both strains expelled the primary infection by day 21. Forty days after the primary infection, we challenged the mice with a second T. spiralis infection and counted tissue eosinophils and worms in the intestine. While wild-type mice developed a large tissue eosinophilia, IL-5 deficient mice showed little increase in eosinophil numbers within the intestine. Throughout the challenge infection, significantly larger worm burdens were recovered from IL-5 deficient mice, and worm expulsion was also significantly slower (day 21) compared to wild-type mice (day 14). Thus, unlike in a primary infection, IL-5 is not only essential for the onset of intestinal eosinophilia, but also makes a significant contribution to enteric host defence during challenge T. spiralis infections.     

Suppression of mucosal mastocytosis by Nematospiroides dubius results from an adult worm-mediated effect upon host lymphocytes

Infections with the nematode Nematospiroides dubius fail to elicit mucosal mast cell (MMC) responses in the intestines of host mice, and suppress MMC responses generated by heterologous infection. Larval N. dubius have the capacity to prime for mastocytosis, and to elicit this response in primed mice during a challenge, but only if adult worms are prevented from developing, either by anthelmintic treatment or by irradiation of the larvae themselves. The suppressive effect of the adult stage was confirmed in experiments where such worms were implanted directly into the intestines of mice primed by exposure to irradiated N. dubius larvae or concurrently infected with Trichinella spiralis. Data on the mechanisms underlying this suppressive effect were obtained from experiments involving the adoptive transfer of mastocytosis by mesenteric lymph node cells (MLNC) from T. spiralis infected mice. When MLNC were taken from mice infected concurrently with both T. spiralis and N. dubius no enhanced mastocytosis was seen in recipients after challenge with T. spiralis. Exposure of MLNC from T. spiralis infected donors to the presence of adult N. dubius after transfer did not reduce the adoptively transferred response. The response was also unaffected when MLNC from adult N. dubius infected mice were simultaneously transferred with MLNC from T. spiralis donors. It is concluded that the suppressive effect of adult N. dubius upon the expression of mucosal mastocytosis acts upon the generation of lymphocytes capable of promoting the development of MMC from precursor cells.     

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.     

Effect of ketotifen on the immune response in BALB/c mice infected with Trichinella spiralis

Infection with Trichinella spiralis in mice generates Th-2 mediated response, which controls effector mechanism operating in the intestine. It is associated with a pronounced intestinal mastocytosis, eosinophilia and destruction of intestinal epithelial layer during expulsion of parasite from the gut. It is believed that protection is dependent on non-specific inflammatory reaction mediated by mast cells. Furthermore, the higher serum levels of parasite specific IgG1 and IgG2a and also mucosal IgA response were related to the course of infection. Inhibition of humoral and cellular immune responses using ketotifen as anti-allergic compound, resulted in the greater worm burden and worm size, but not in the significant prolongation of intestinal phase. Moreover, in treated mice epithelial layer of the gut was protected from destruction provoked by the nematode. As interaction between effector leukocytes and antibodies were not effective it was proposed that other mechanisms, not related to hypersensitivity or conventional inflammatory response regulated the level of infection. The immunological and physiological phenomenons are discussed in terms of events associated with protection to the parasite. Possibly, immunoregulatory capasity of the nematode is involved in the induction of multiple mechanisms operated during infection.     

Distribution of intestinal mast cell proteinase in blood and tissues of normal and Trichinella-intected mice

A sensitive and specific enzyme-linked immunosorbent assay (ELISA) was developed for mouse intestinal mast cell proteinase (IMCP). Specificity was demonstrated by the absence of immunoreactivity with extracts of isolated serosal mast cells (SMC), or with high concentrations (50 micrograms/ml) of the antigenically similar rat mast cell proteinases I or II. The small and large intestines in normal mice were the major sources of IMCP, there being little or no IMCP in non-mucosal tissues. Concentrations of IMCP in normal (non-parasitized) mice were low, but were increased 100-1000-fold intestines of mice infected 10 days earlier with Trichinella spiralis. The kinetic response of secreted IMCP into the blood of mice following infection with T. spiralis was also studied. Systemic release of IMCP coincided with the immune expulsion of adult worms from the intestine, and peak concentrations (9.45 micrograms/ml IMCP) occurred 9 days after infection. The tissue distribution of IMCP, its secretion into blood, and its enteric accumulation during parasite infection, are consistent with a mucosal mast cell (MMC) source for IMCP. The results are discussed in the context of similar findings for rat mast cell proteinase II.     

Physiological characterization of a biphasic immune response to Trichinella spiralis in the rat.

Secondary infection with Trichinella spiralis in the rat was associated with a host response that prevented approximately 80% of the total number of larvae recovered after primary infection from embedding in the intestine. The host response occurred within 15 min after contract of the parasite with intestinal mucosa and was not associated with acute inflammatory cell infiltrates or with the pathophysiology of the primary infection. Eventual rejection of the residual population of embedded worms occurred between four and eight days after infection and involved tissue changes similar to those attending worm rejection during primary infection. Elimination of enteric stages of T. spiralis in primary infection probably involves a single response aimed at the expulsion of established worms. In contrast, immune rejection of worms in secondary infection involves physiologically and presumably immunologically distinct "early" and "late" responses, with each response having a different developmental stage of the parasite as its target.     

以旋毛虫成虫感染小鼠的研究

本文以旋毛虫成虫为感染期感染小鼠获得成功。用２００条旋毛虫成虫经口感染小鼠，在鼠的肠内发现成虫，肌肉内发现幼虫。实验结果显示，２日龄成虫感染的１０只鼠肠内幼虫数６～５７条，平均３０．８条，肌肉内幼虫数１７～７３条，平均３８．１条。７日龄成虫感染的１０只鼠肠内检获成虫数２～３４条，平均１８．４条，肌肉内幼虫数０～５５条，平均２５．４条。１５日龄成虫感染的１０只鼠肠内成虫数０～８条，平均２；２条２只鼠的肌肉内有幼虫，分别是２和３条。３０日龄成虫感染的小鼠肠内和肌肉内未见成虫和幼虫。因此，可以认为在旋毛虫生活史过程中，旋毛虫成虫亦能起感染期作用感染宿主。     

Variability of the intestinal immunoglobulin E response of rats to infection with Trichinella spiralis, Heligmosomoides polygyrus or Nippostrongylus brasiliensis

Total intestinal IgE level increased in rats infected with Trichinella spiralis or Heligmosomoides polygyrus (peak levels of 2.6 microg and 3.7 microg, respectively), but not in rats infected with Nippostrongylus brasiliensis. Intestinal implantation of young adult N. brasiliensis did not stimulate an intestinal immunoglobulin (Ig)E response, suggesting that mucosal penetration may be required for local intestinal IgE responses in rats. During a T. spiralis infection, total IgE levels in the intestinal lumen were consistently higher in LEWIS and LOU rats (rat strains that eliminate T. spiralis worms earlier in the infection) than in PVG, AO and WKA/H strain rats. There was no correlation in either the total level of serum IgE and IgA, or of intestinal IgA with differences between strains in the rate of worm elimination from the gut. Furthermore, the intestinal IgE immunoprecipitated from LEWIS rats 12 days after infection reacted with T. spiralis adult worm metabolic antigens, while intestinal IgE from PVG rats only became reactive with adult worm metabolic antigens from 14 days after infection. These data emphasize the significance of the intestinal IgE response and its unique features by comparison with serum IgE and IgA or intestinal IgA.     

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     

Trichinella spiralis: Intestinal expression of systemic stage-specific immunity to newborn larvae

Rats immunized with newborn Trichinella spiralis larvae i.v. were found to confer a specific anti-newborn larvae immunity in the small intestine. In rats immunized with newborn larvae i.v. and then challenged with adult worms intraintestinally, total newborn larvae recovery was reduced by 75-90% in thoracic duct lymph and in hepatic portal vein blood. No newborn larvae were found in the peritoneal fluid of immunized rats. In addition to an absolute reduction in number, larval migration from the small intestine to the thoracic duct was delayed by 6-12 h and migration to the portal vein was inhibited for at least 8 h. The establishment of adult worms in the small intestine and female worm fecundity were not affected by anti-newborn larvae immunity. Identical quantitative effects on newborn larvae migration from the small intestine were achieved by homologous transfer of anti-newborn larvae immune serum i.v. into naive recipient rats.     

Immunoglobulin class specific responses to biochemically defined antigens of Trichinella spiralis

A comparison of the humoral response to resistant (NIH) and susceptible (C3H) strains of mice, which reject adult worms at different rates during a primary infection, was made following infection with Trichinella spiralis. The serum concentration of immunoglobulins of the heavy chain classes IgM, IgG1, IgG2, IgG3 and IgA were determined by single radial immunodiffusion. Antibodies of the same immunoglobulin isotypes to biochemically defined, stage specific surface and secreted components of three stages of parasite development were also determined using an isotype specific immuno-coprecipitation assay. Independent variation of the responses of each immunoglobulin isotype was observed. The specific anti-parasite response did not reflect total serum immunoglobulin levels in all immunoglobulin classes, and this is discussed in relation to basic mechanisms of immunoglobulin class switching. Finally a close correlation was observed in resistant (NIH) mice between the production of IgA antibody to surface components of adult worms and accelerated expulsion of this stage of the worm from the gastrointestinal tract. The possible relevance of this IgA response is further indicated by the failure of susceptible mice to synthesise IgA antibodies to the same surface antigens.     

合欢皮总皂苷治疗旋毛虫感染小鼠的疗效观察

目的研究合欢皮总皂苷对感染旋毛虫小鼠的治疗效果。方法将36只感染旋毛虫的ICR小鼠随机分为6组(每只小鼠感染300条旋毛虫),每组6只。组Ⅰ-Ⅲ为成虫组:组Ⅰ为感染对照组,组Ⅱ为合欢皮总皂苷治疗组,组Ⅲ为阿苯达唑治疗组;组Ⅳ-Ⅵ为肌幼虫组:组Ⅳ为感染对照组,组Ⅴ为合欢皮总皂苷治疗组,组Ⅵ为阿苯达唑治疗组。Ⅰ、Ⅱ、Ⅲ组于感染后第2d开始给药,连续给药3d,于感染后第7d处死,计数小肠内成虫;Ⅳ、Ⅴ、Ⅵ组于感染后第7d开始给药,连续给药14d,于感染后第40d处死,计数肌幼虫并计算减虫率,HE染色计数肌幼虫,免疫组化检测膈肌中IL-1β,IL-6,TNF-α,COX-2因子的表达。结果合欢皮总皂苷和阿苯达唑治疗组成虫数和肌幼虫数均少于感染对照组(P<0.01),成虫减虫率分别为71.60%和81.24%,肌幼虫减虫率分别为65.70%和89.94%;HE染色结果表明两个治疗组囊包幼虫均减少,炎症细胞表达均明显减轻;免疫组化结果显示治疗组IL-1β,IL-6,TNF-α,COX-2的表达降低。结论合欢皮总皂苷对旋毛虫成虫和囊包幼虫均有较好的杀虫效果,虽然效果略次于阿苯达唑,但其作为中药提取物毒性较低。     

Establishment of T-Helper-2 immune response based gerbil model of enteric infection

BACKGROUND: The reciprocal antagonism of T-helper-1 (Th-1) and Th-2 type immune responses suggests that helminth parasitic infection may ameliorate disease where a Th-1 type response dominates. The Mongolian gerbil has been useful in the investigation of the pathogenesis of gastric cancer, since long-term infection of gerbils with Helicobacter pylori induces adenocarcinoma. In this study the kinetics of worm expulsion and associated immune responses in gerbils infected with Trichinella spiralis were investigated in an attempt to establish an animal model of parasitic infection that could be helpful when investigating the effect of a Th-2 type response on Th-1-based intestinal disorders. METHODS: Gerbils were infected with various doses of infective T. spiralis larvae and were euthanized on different days after infection to investigate the intestinal worm recovery, goblet cell population, eosinophil response and serum IgG1 responses. RESULTS: The number of worms recovered from the intestine was dependent on the number of larvae used for the infection. Almost all worms were expelled spontaneously by day 26 post-infection, when the gerbils had been infected with 375 or 750 larvae. The number of intestinal goblet cells, eosinophils and the serum IgG1 level significantly increased following infection compared with the control. CONCLUSION: This is the first comprehensive report on the time-course of T. spiralis infection in gerbils. The data indicate that the T. spiralis-infected gerbil could be used as a model of the Th-2-based response to investigate the effect of a parasite-induced Th-2 response on various Th-1-mediated intestinal disorders such as H. pylori-induced gastritis and gastric carcinoma.     

Comparative dynamics and phenotype of the murine immune response to Trichinella spiralis and Trichinella pseudospiralis

Infection of NIH mice with Trichinella spiralis and Trichinella pseudospiralis results in qualitatively comparable immune responses. Antigen-specific proliferation by mesenteric lymph node cells was transient and temporally associated with intestinal infection, but in contrast was sustained throughout infection by splenocytes. Early cytokine production by mesenteric lymph node cells was dominated by interleukin 10, but also IL-5 and IL-4, with rapid resolution following parasite expulsion from the gut. Splenocytes showed a mixed profile of cytokine production, although again dominated by IL-10 and sustained over 60 days of infection. All antibody classes were evident, with early production of IgA and IgG1, and subsequent secretion of other subclasses including IgG2a. Granulocytic infiltration of the spleen was significantly greater in T. spiralis infection. The concentration of serum corticosterone generally remained within normal boundaries, although was raised by day 60 in T. spiralis-infected mice. We conclude that the systemic suppression of inflammation reported for T. pseudospiralis does not result from selective induction of regulatory cytokines, or a major difference in the immune response to infection with T. spiralis.     

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.     

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.     

旋毛虫幼虫抗原接种小鼠诱发保护性免疫的研究

本文就旋毛虫幼虫可溶性抗原接种小鼠诱发保护性免疫进行了研究,结果:两组免疫小鼠的成虫减虫率分别为41.3％和34.7％,肌肉幼虫的减虫率61.5％和44.8％,抗旋毛虫抗体水平明显升高,GMRT比对照组高119倍。免疫组的白细胞移动率为57％和63％,血液嗜酸性粒细胞显著增多,肌肉幼虫囊包周围炎症反应面积增大。实验表明旋毛虫幼虫可溶性抗原可诱发特异性细胞免疫和体液免疫,对攻击感染具有明显的保护作用。     

旋毛虫排泄分泌抗原对小鼠的保护性免疫

目的比较旋毛虫成虫排泄分泌抗原(ES抗原)、肌幼虫ES抗原、成虫和肌幼虫ES混合抗原对小鼠的免疫保护作用。方法用生理盐水培养法从培养液中提取成虫ES抗原、肌幼虫ES抗原,分别用成虫ES抗原、肌幼虫ES抗原、成虫和肌幼虫ES混合抗原免疫小鼠,同时设佐剂组和对照组,间隔7d共免疫3次。末次免疫后7天,每只小鼠用200条旋毛虫感染期幼虫经口进行攻击感染。感染后7天和30天检查各组小鼠肠道成虫数和肌幼虫数。结果旋毛虫成虫ES抗原组、肌幼虫ES抗原组、成虫和肌幼虫ES混合抗原组的成虫减虫率分别为87.95%、69.48%、84.34%,肌幼虫减虫率分别为74.79%、87.97%、86.87%。成虫ES抗原组、成虫与肌幼虫ES抗原混合组的成虫减虫率均高于肌幼虫ES抗原组(P均<0.05)。肌幼虫ES抗原组、成虫与肌幼虫ES抗原混合组的肌幼虫减虫率均高于成虫ES抗原组(P均<0.01)。结论旋毛虫成虫和肌幼虫ES混合抗原均能诱导小鼠产生抗成虫及肌幼虫较强的免疫力。     

碳酸氢钠对旋毛虫幼虫感染性及生殖力的影响

目的观察碳酸氢钠对旋毛虫幼虫感染性及生殖力的影响。方法将旋毛虫肌幼虫在体外经1%碳酸氢钠处理不同时间后观察其活力。100只雄性昆明小鼠随机分成10组(每组10只),1～3组中每组5只分别喂饲经碳酸氢钠或生理盐水浸泡不同时间(24、36、48h)含300条旋毛虫肌幼虫的小鼠肌肉(约0.02g);4～9组分别用不同剂量碳酸氢钠或食用醋(总酸浓度4.5%,pH3.05)灌胃后0.5h喂饲含300条肌幼虫肉块,10组为灌服生理盐水对照组。于喂饲后第7天和第42天每组剖杀5只小鼠,分别观察肠道成虫数、肌幼虫数及生殖力指数(RCI)。结果肌幼虫经碳酸氢钠处理24～240h的死亡率与生理盐水对照组相比差异无统计学意义(P0.05)。小鼠喂饲经碳酸氢钠处理24、36h和48h旋毛虫肌幼虫后42d,其肌幼虫数(84467、84600条和82300条)均明显高于生理盐水对照组(12650、6460条和1240条)(P0.05)。灌饲0.4、0.6ml碳酸氢钠小鼠的肠道成虫数(193、203条)与RCI(323.77、326.55)均明显高于食醋对照组(68、67条;217.55、195.33)及生理盐水对照组(145条,268.13)(P0.05)。结论碳酸氢钠可明显增加旋毛虫的感染性与生殖力。