日本血吸虫感染新模型小鼠Th1/Th2细胞因子水平的动态变化

目的在建立日本血吸虫感染小鼠伴随免疫新模型的基础上,通过观察比较新模型小鼠与常规感染小鼠脾细胞经不同抗原刺激后诱生的Th1细胞因子(IFN-γ)和Th2细胞因子(IL-4)水平的动态变化,探讨日本血吸虫感染小鼠伴随免疫新模型的细胞免疫机制。方法小鼠感染日本血吸虫尾蚴20 d后,按300 mg/kg.d腹腔注射酚酶抑制剂丙烯基硫脲,持续抑制雌虫产卵,建立日本血吸虫感染小鼠伴随免疫新模型。同时设立常规模型对照组和正常小鼠对照组。在感染后第0、3、6、9和12周,取各组小鼠脾细胞进行体外培养,并分别用可溶性成虫抗原(SWAP)、可溶性虫卵抗原(SEA)及非特异性抗原刀豆素(ConA)诱导脾细胞产生细胞因子,应用ELISA方法测定培养上清液中IFN-γ和IL-4的含量。结果新模型组与常规模型组IFN-γ和IL-4变化趋势基本一致,其中IFN-γ均在感染后4~6周开始上升,7~9周达到高峰,10~12周逐渐下降并恢复至感染前水平;IL-4均在感染后第6周开始逐渐升高,直至12周仍维持高水平;而正常组IFN-γ和IL-4均无明显变化。新模型组经SEA刺激后产生的IFN-γ水平,以及经SWAP和SEA刺激后产生的IL-4水平均显著低于常规模型组(P<0.05);而经SWAP刺激产生的IFN-γ水平显著高于常规模型组(P<0.05)。在3种不同的抗原中,ConA组产生的IFN-γ和IL-4水平均显著高于SEA组和SWAP组(P<0.05)。结论日本血吸虫感染小鼠伴随免疫新模型与血吸虫常规感染小鼠的细胞免疫功能变化趋势基本一致,表现为感染早期以Th1细胞应答为主,然后逐渐向Th2细胞极化。     

日本血吸虫感染小鼠脾细胞TNF诱生水平的动态研究

本文报道小鼠感染日本血吸虫不同阶段,脾细胞体外诱生TNF水平的动态.实验采用8wk龄C_(57)BL/6小鼠,每鼠经腹部皮肤感染日本血吸虫尾蚴25条.感染后2、4、6、7、8、10、12和14wk,小鼠脾细胞以SEA或LPS刺激,作TNF体外诱生和活性检测.结果表明:TNF活性在感染后第6wk开始明显上升,第7—8wk达高峰,第10wk开始下降,以SEA诱生的TNF在第12wk以后未能测出其活性.LPS诱生组的TNF活性动态基本与SEA诱生组一致,但前组TNF水平明显高于后组.     

日本血吸虫感染新模型小鼠IFN-γ及IL-4 mRNA的动态变化

目的 构建日本血吸虫感染小鼠伴随免疫新模型,通过观察比较新模型小鼠与常规感染小鼠脾细胞诱生Th1细胞因子（γ-IFN）和Th2细胞因子（IL-4）mRNA的动态变化,从分子水平探讨日本血吸虫感染小鼠伴随免疫新模型的细胞免疫机制。方法 小鼠感染日本血吸虫尾蚴20d后,按300 mg/kg.d腹腔注射丙烯基硫脲,持续抑制雌虫产卵,建立日本血吸虫感染小鼠伴随免疫新模型。同时设立常规模型对照组和正常小鼠对照组。在感染后第2,3,6,9和12 w,采用RT-PCR对各组小鼠脾细胞IFN-γ和IL-4的mRNA水平进行半定量检测分析。结果 新模型组与常规模型组小鼠IFN-γ和IL-4 mRNA水平变化趋势基本一致,IFN-γmRNA水平在感染后9w最强,然后逐渐下降,至第12w;IL-4 mRNA水平在感染后3w开始逐渐增强,至12w仍维持高水平。新模型组IFN-γmRNA水平在感染3w后明显高于常规模型组（P〈0.05）;常规模型组IL-4 mRNA水平在感染6w后明显高于新模型组（P〈0.05）。正常小鼠IFN-γ和IL-4 mRNA水平较低,均无明显变化。结论 日本血吸虫感染新模型小鼠与常规模型小鼠的细胞免疫功能变化趋势基本一致,表现为Th1淋巴细胞功能先升高,然后逐渐向Th2淋巴细胞功能极化,提示可溶性虫卵抗原（soluble egg antigen,SEA）不是诱导Th2功能极化的唯一因素,对细胞免疫应答由Th1向Th2功能极化有促进作用。     

寄生虫感染与细胞因子

本文分别从原虫，血液和组织内蠕虫、肠道蠕虫感染以及寄生虫免疫避等四个方面阐述了与细胞因子的关系。     

细胞因子与感染

细胞因子是联系细胞间相互作用的一种化学物质，他们是蛋白或糖蛋白质，由一组细胞分泌，同类细胞或其他细胞通过特殊受体来识别之，从信号功能上看，细胞因子很像内分泌激素，但细胞因子大多数是释放在细胞周围短距离传递信号，而内分泌是分泌至血液远距离传递。这些分泌...     

旋毛虫感染鼠及其子代小鼠血清被动转移抗血吸虫感染的保护性

旋毛虫病和血吸虫病都是严重危害人畜健康的寄生虫病。动物实验发现，小鼠感染旋毛虫后能产生对日本血吸虫感染的抵抗力，用旋毛虫肌蚴抗原免疫小鼠亦能产生抗日本血吸虫保护性。彭飞等研究表明，旋毛虫和日本血吸虫之间存在交叉抗原。近来经动物实验证明，感染旋毛虫的母鼠产下的小鼠也具有对血吸虫感染的保护性，为了解该交叉抗原所引起的保护性能否经血清被动转移给受体动物，     

日本血吸虫感染小鼠脾细胞IL—2及IFN—γ动态观察

本文观察８ｗｋ龄Ｃ５７ＢＬ／６小鼠感染日本血吸虫尾蚴后不同时期脾细胞经ＳＥＡ或ＣｏｎＡ刺激，体外诱生的ＩＬ－２和ＩＦＮ－γ活性变化。结果表明两种细胞因子活性均在感染后第４－６ｗｋ开始上升，第６—８ｗｋ达高峰，第１２—１４ｗｋ恢复至感染前水平。ＩＦＮ－γ高峰时间略先于ＩＬ－２。非特异性刺激原诱生组和特异性刺激原诱生组各阶段细胞因子活性动态基本一致，前组活性高于后组。提示ＩＦＮ－γ与ＩＬ－２活性与血吸虫卵肉芽肿的诱导、成熟与维持有密切关系。     

灭活血吸虫卵预防小鼠实验性结肠炎的实验研究

目的 研究血吸虫卵对小鼠三硝基苯磺酸(TNBS)所致结肠炎的预防作用及其机制.方法 TNBS灌肠诱导小鼠结肠炎模型.60只小鼠均分为对照组(不予任何处理)、干预组及模型组.干预组小鼠于造模前第14天和第3天分别腹腔内注射冰冻灭活的血吸虫卵10000个.模型组小鼠造模前腹腔内注射0.9%氯化钠溶液.造模后第7天处死存活小鼠,统计小鼠死亡率.观察结肠形态和病理特征.实时PCR法测定结肠组织中干扰素(IFN)-γ及白细胞介素(IL)-10 mRNA表达.ELISA法测定血清中IFN-γ及IL-10活性.结果 干预组小鼠死亡率较模型组显著下降(20%比50%,P＜0.05),结肠组织炎性反应显著减轻(Ameho-criteria评分:1.58±0.5比4.18±0.8,P＜0.05),结肠组织及血清中IFN-γ活性显著下降[血清:(29.79±6.97)pg/ml比(48.33±16.59)pg/ml,结肠:(2.31±1.08比7.23±3.52)P＜0.053、IL-10活性显著升高[血清:(38.22±9.96)pg/ml比(28.87±5.74)pg/ml,结肠:7.44±3.04比3.68±1.58 P＜0.05].结论 腹腔内注射血吸虫卵能减轻TNBS所致小鼠实验性结肠炎肠道炎性反应,可能与血吸虫卵提高结肠组织和血清中IL-10活性、降低INF-γ活性有关.     

日本血吸虫尾蚴经口腔粘膜感染小鼠的可行性研究

在寄生虫学与寄生虫病的科学研究与教学活动中 ,经常使用家兔和小鼠作为血吸虫病的动物模型 ,过去通常用经腹壁皮肤或经腹腔注射尾蚴的方法感染动物。经查阅NationalLibraryofMedicine、中国期刊网CNKI数字图书馆及维普资讯镜像站中刊数据库检索系统 ,尚未见尾蚴经口腔粘膜感染动物方法的相关文献报道。本实验进行了经口腔粘膜感染的可行性研究。1　材料与方法1.1　日本血吸虫尾蚴　阳性钉螺由湖南省寄生虫病防治研究所提供 ,以 2～ 4只 /管分别放入指管内 ,管内注满冷开水 ,置于2 5℃有光照的温箱内孵育 4～ 8h ,待尾蚴逸出后备用。1.2…     

Eosinophil activation status, cytokines and liver fibrosis in Schistosoma mansoni infected patients

We have been investigating whether human eosinophils play an important role in schistosomiasis mansoni morbidity. Our main focus has been on the activation-related cell surface markers (CD23/CD69/CD25/HLA-DR/CD28/CD80) and the detection of TNF-alpha, IL-4 and IL-5 in peripheral blood eosinophils from chronic Schistosoma mansoni-infected patients. Our studies compare both, intestinal (INT) and individuals with periportal fibrosis (FIB). Our major findings, point to distinct profile of activation-related surface markers on eosinophils as the hallmark of disease morbidity during chronic S. mansoni infection. Up-regulation of several activation-related markers was observed on eosinophils from FIB group, but not INT, which include early activation markers, such as CD69 and CD23. INT displayed a distinct profile, with up-regulation of molecules related to the late activation (CD25, HLA-DR, CD28 and CD80). These results suggest that some immunoregulatory events may take place controlling the early eosinophil activation in the INT group. Higher levels of eosinophil-derived cytokines were observed in FIB, regardless the antigen stimulation in vitro. A mixed cytokine pattern, characterized by positive correlation between TNF-alpha, IL-4 and IL-5 was observed in both INT and FIB. However, lack of correlation between the cytokine expression and the eosinophil activation status points out that even those FIB patients presenting minor increment on eosinophil activation displayed higher levels of cytokine-positive eosinophils. Indeed, the positive association between lymphocyte-derived IL-10 and the eosinophils cytokine profile was observed exclusively in INT further emphasize our hypothesis that immunoregulatory events take place controlling disease morbidity in human schistosomiasis. The impaired IL-10-driven immunoregulatory function may play an important role on the establishment of pathology in patients bearing periportal fibrosis.     

Variation of hepatic fibrosis and granuloma size among mouse strains infected with Schistosoma mansoni

To investigate the relation between the size of circumoval granulomas and hepatic fibrosis, a variety of mouse strains infected with Schistosoma mansoni were examined and the number of eggs in the tissues, the fibrotic responses to the eggs, and the volume of the granulomas were determined. Marked differences in granuloma volume and in hepatic fibrosis were found between mouse strains, and those strains with the largest granulomas also showed the most hepatic fibrosis. On the other hand no significant correlation between granuloma size and hepatic fibrosis was found in the progeny of the F2 generation and backcrosses between F1 mice and the parental strains when crosses were made between Nmri mice (high granuloma volume and high fibrosis) and C57BL/6 mice (low granuloma volume and low fibrosis). Hepatic fibrosis per egg decreased with increasing infection intensity while granuloma volume was unaffected, indicating that fibrosis and granuloma size are at least in part modulated by different factors. The number of eggs found in the tissues per worm pair and the proportion of eggs in the liver also decreased as infection intensity increased. Some influence of the major histocompatibility complex on both granuloma size and fibrosis was found. Congenic mice on the C57BL/10 and C3H/HeSn backgrounds showed larger granulomas in H-2b than in H-2k mice, but no such correlation was found in comparing C57BL/6 mice with B6.H-2k mice. Less hepatic fibrosis was found in B10.M (H-2f), B10.SM (H-2v), and B10.RIII (H-2r) animals than in C57BL/10 mice. The regulation of granuloma size and of hepatic fibrosis is clearly complex and involves genes both outside of and within the major histocompatibility complex.     

Occurrence of myocarditis in rodents infected with Schistosoma mansoni

Myocarditis is a complication of Schistosoma mansoni infection, although the literature does not provide much information regarding the frequency of myocarditis. In order to analyze the relationship between myocarditis and S. mansoni infection, different laboratory animals were infected with different dose of cercariae. At different weeks of post infection the hearts of infected animals were collected and processed for histopathological examination. Myocarditis was characterized by interstitial inflammatory cell infiltration with or without granuloma. ddY and ICR infected mice showed eosinophilic egg-granuloma in the heart where as neither eosinophil nor egg-granuloma were observed in the heart of infected gerbils. Higher number of eosinophils and greater size of the granuloma were found in the ddY mice than ICR mice. The number of eosinophils was significantly higher in severe myocarditis. Incidence of myocarditis was higher in ddY mice (69% with 100) than ICR mice (35%) and gerbils (23%). The results indicate that ddY mice were more susceptible to S. mansoni infection in the development of myocarditis and myocardial severity was associated with greater eosinophil infiltration. These findings suggest that eosinophils might be involved in the development of myocarditis, although the involvement of immunological reaction can not be ruled out.     

Salmonella paratyphi A in hamsters concurrently infected with Schistosoma mansoni

The present work deals with the development of an improved animal model to study the association of salmonellosis and schistosomiasis. The animal chosen was the hamster, Mesocricetus auratus, which can be readily infected with Schistosoma mansoni. Normal hamsters and schistosome-infected hamsters (SIH) were given approximately 2.0 x 10(7) Salmonella paratyphi A intracardially. It was found that S. mansoni infections enhanced and prolonged the growth of S. paratyphi A in hamsters. Animals with dual infections had increased mortality in comparison with those infected with just bacteria or parasite during the 50 days post-bacterial challenge. Further studies showed that in SIH, S. paratyphi A persisted in various organs for up to 8 weeks post infection. In contrast, concurrent Leishmania donovani infections have no effect on S. paratyphi A infections. Significant numbers of bacteria were cultured from well-washed schistosome worms recovered from SIH 6--8 weeks post-bacterial challenge. These findings suggest that a direct physical relationship between the bacteria and worms facilitates the establishment and growth of S. paratyphi A in vivo, and that a deficit in host immune response is not a major factor involved in the enhanced growth of S. paratyphi A.     

Risk of hepatitis B infection among Egyptians infected with Schistosoma mansoni

Three hundred twenty-four individuals in a farming village located in the Nile Delta of Egypt were serially tested for hepatitis markers and Schistosoma mansoni to determine whether there is an increased risk of hepatitis B in persons infected with schistosomiasis. One-half of the subjects had stools positive for S. mansoni. Thirty-seven percent of the individuals had been infected with hepatitis B, and 3% were chronic HBsAg carriers. No statistical association was found between S. mansoni infection and hepatitis B infection, including chronic hepatitis B. Although there was no evidence of an association between these 2 pathogens, larger nonhospital based studies are needed to resolve this question.     

Increased hepatotoxicity of bacterial lipopolysaccharide in mice infected with Schistosoma mansoni

Mice infected with Schistosoma mansoni were highly sensitive to the lethal effects of bacterial lipopolysaccharide (LPS). The hyper-reactive state of LPS coincided with the development around the parasite eggs of multiple granulomas in the liver. Elevated aspartate transaminase levels in blood and severe hypoglycaemia in LPS-challenged animals indicated extensive liver parenchymal cell damage. There was also a complete depletion of glycogen in hepatocytes of these animals. From this work and studies on other hepatitis models, it is suggested that individuals affected with granulomatous disorders may be at risk because of everyday exposure to LPS from the gut.