树突状细胞在寄生虫感染中的作用

树突状细胞是一类重要的抗原提呈细胞 ,在宿主针对寄生虫感染的免疫应答过程中起到了重要作用。该文通过分析血吸虫、疟原虫、利什曼原虫、弓形虫、锥虫、丝虫等寄生虫感染的研究现状 ,对树突状细胞在诱导机体保护性免疫以及参与形成寄生虫免疫逃避中的作用机制作进一步介绍     

树突状细胞在寄生虫感染中的作用

树突状细胞是一类重要的抗原提呈细胞，在宿主针对寄生虫感染的免疫应答过程中起到了重要作用。该文通过分析血吸虫、疟原虫、利什曼原虫、弓形虫、锥虫、丝虫等寄生虫感染的研究现状，对树突状细胞在诱导机体保护性免疫以及参与形成寄生虫免疫逃避中的作用机制作进一步介绍。     

刚地弓形虫抗肿瘤作用及其机制研究进展

刚地弓形虫是一种重要的机会致病性原虫,严重威胁着人类健康,但弓形虫虫体、培养上清/排泄分泌抗原、裂解抗原、分泌蛋白均被证实具有显著的抗肿瘤作用。其中,诱导肿瘤细胞凋亡、抑制肿瘤组织新生血管生成以及增强宿主自身免疫细胞功能的机制在弓形虫抗肿瘤过程中发挥着关键作用。本文综述了弓形虫抗肿瘤作用的研究进展,以及虫体及其相关组分抗肿瘤作用的相关机制。     

肝片吸虫对抗百日咳杆菌保护性Th1应答的抑制

百日咳杆菌感染或百日咳疫苗免疫后可诱导较强的抗原特异性Th1应答,对宿主抗感染起关键作用,其中IFN-γ在控制百日咳杆菌感染以及抑制细菌在粘膜部位寄生起重要作用。肝片吸虫感染的宿主主要产生Th1应答。本文的研究目的在于探讨体内细菌病原体诱导的Th1和寄生虫诱导的Th1的相互影响。 实验中所用的抗原包括经甲醛处理的百日咳杆菌的超声粉碎物(BPS),百日咳杆菌     

寄生虫病疫苗研究的现状及展望

疫苗是控制乃至消灭传染性疾病的有效手段。寄生虫疫苗研究始于1903年,至今已有100多年历史。在低毒活疫苗、致弱活疫苗、灭活或死病原疫苗、亚单位疫苗(包括抽提物或代谢产物)、合成的和重组抗原疫苗、抗独特型疫苗和D N A疫苗等方面做了大量的实验研究,有的进行了现场验证。虽有证据表明几乎全部寄生虫感染后宿主存在获得性免疫或对再感染的抵抗力,但寄生虫抗原免疫所诱导的大多为部分保护性免疫力(一般为30%7～0%),很难像病毒和细菌抗原那样诱导出99%或99.9%的保护性免疫力。究其原因,主要与以下方面有关:多数寄生虫为复细胞生物,或生…     

宿主排泄分泌物中寄生虫抗原的检测及其应用

宿主排泄分泌物中的寄生虫抗原是一类循环抗原(CAg),属可溶性多糖抗原。这类CAg除存在宿主血液和组织中,还可随人和动物的排泄物和腺体分泌物排出体外。随着寄生虫免疫学的迅猛发展,对宿主排泄分泌物中寄生虫抗原的研究日益增多。目前已报道在感染宿主的粪、尿和乳汁、阴道分泌物中检测到10多种寄生虫抗原。检测和研究这类抗原对于寄生虫感染的早期诊断、疗效考核以及流行病学等方面的研究都具有重要意义。     

蠕虫感染与过敏性和自身免疫性疾病

许多研究发现蠕虫感染后虫源性分子诱导免疫细胞形成免疫调节网络,介导免疫抑制,从而抑制过敏性和自身免疫性疾病。寄生虫可以通过诱导免疫调节细胞活化和产生细胞因子发挥抑制效应,从而影响其他免疫相关疾病。然而,蠕虫感染与免疫相关疾病之间的调节机制尚无明确的结论。一些蠕虫感染可以保护和控制过敏性疾病,而另一些蠕虫却加剧疾病的免疫病理损害。     

凋亡在寄生虫与宿主相互关系中的作用

细胞凋亡是指细胞在一定的生理或病理条件下,受内在遗传机制的控制自动结束生命的哪过程.细胞凋亡普遍存在于低等到高等生物中,受着精密的调控.寄生虫感染宿主细胞后可诱导或抑制细胞凋亡,成为寄生虫致病机制以及免疫逃避方式之一.深入了解寄生虫与宿主相瓦关系中凋亡的作用及其信号通路,可进一步丰富寄生虫与宿主相互关系的理论体系,为研发新型抗寄生虫药物提供候选靶点,从而更好地控制寄生虫病.     

凋亡在寄生虫与宿主相互关系中的作用

细胞凋亡是指细胞在一定的生理或病理条件下,受内在遗传机制的控制自动结束生命的哪过程.细胞凋亡普遍存在于低等到高等生物中,受着精密的调控.寄生虫感染宿主细胞后可诱导或抑制细胞凋亡,成为寄生虫致病机制以及免疫逃避方式之一.深入了解寄生虫与宿主相瓦关系中凋亡的作用及其信号通路,可进一步丰富寄生虫与宿主相互关系的理论体系,为研发新型抗寄生虫药物提供候选靶点,从而更好地控制寄生虫病.     

凋亡在寄生虫与宿主相互关系中的作用

细胞凋亡是指细胞在一定的生理或病理条件下,受内在遗传机制的控制自动结束生命的哪过程.细胞凋亡普遍存在于低等到高等生物中,受着精密的调控.寄生虫感染宿主细胞后可诱导或抑制细胞凋亡,成为寄生虫致病机制以及免疫逃避方式之一.深入了解寄生虫与宿主相瓦关系中凋亡的作用及其信号通路,可进一步丰富寄生虫与宿主相互关系的理论体系,为研发新型抗寄生虫药物提供候选靶点,从而更好地控制寄生虫病.     

旋毛虫抗肿瘤机制研究进展

旋毛虫具有抗多种肿瘤的作用,宿主感染的旋毛虫数量不同,其体内肿瘤受抑制程度亦不同;宿主在感染旋毛虫后的不同时间接种肿瘤细胞,体内肿瘤的生长速度降低程度也不同。旋毛虫在宿主体内发育的不同阶段,均可能具有抗肿瘤作用。旋毛虫通过细胞免疫、肿瘤抗原和抗肿瘤活性物质发挥抗肿瘤作用。     

CF mediated G1 arrest is associated with induction of p27(Kip1) and inhibition of cyclin D1 expression in human hepatoma HepG2 cells.

CF is a kind of diterpenoid which was first isolated and purified from Chinese tropical plants by our laboratory. Our previous works have demonstrated it could inhibit the proliferation of several malignant tumor cell lines and stimulate them to differentiate to normal cells. In this article we investigated the effect of CF on human hepatocellulor carcinoma HepG2 cell viability, differentiation, cell cycle distribution and G1 cell cycle related genes expression. We also detected the effect of retinoic acid (RA) which was used as positive control and the effect of combination CF+RA. Our data suggested that CF could be useful to induce growth arrest and differentiation in HepG2 cell lines, and could reverse the transformed phenotype. This anti-tumor effect was due to G1 arrest in cell cycle which was associated with an increase of p27(Kip1) and a decrease of cyclin D1 expression, so CF might be a useful targeted therapy strategy for HCC. Results also showed RA has a different mechanism from CF on G1 arrest, and CF has not synergistic anti-tumor effect with RA on HepG2 treatment.     

凋瘤方剂对荷瘤小鼠抑瘤作用的实验研究

目的 :探讨凋瘤方剂抑瘤作用机制。方法 :S- 180腹水瘤细胞造模 ,观察小鼠外周血白细胞、脾脏和胸腺重量的变化 ,检测瘤细胞分裂相、巨噬细胞的吞噬功能和瘤细胞内的凋亡细胞 ,并将正常对照组、肿瘤对照组、凋瘤方剂组、环磷酰胺组、环磷酰胺加凋瘤方剂组进行比较。结果 :凋瘤方剂抑瘤率达 5 4.2 0 %,对骨髓血象无任何毒副作用 ,脾脏重量重于正常对照组 (P <0 .0 5 ) ,瘤细胞分裂相减少 ,巨噬细胞、凋亡细胞明显增加。结论 :凋瘤方剂对荷瘤小鼠具有明显的抑瘤作用。     

Dauricine can inhibit the activity of proliferation of urinary tract tumor cells

ObjectiveTo explore the anti-tumor effects of asiatic moonseed rhizome extraction-dauricine on bladder cancer EJ cell strain, prostate cancer PC-3Mcell strain and primary cell culture system.MethodsThe main effective component-phenolic alkaloids ofMenispermum dauricum was extracted and separated from asiatic moonseed rhizome by chemical method. MTT method was used to detect dauricine anti-tumor effect.ResultsDauricine had an obvious proliferation inhibition effect on the main tumor cells in urinary system. The minimum drug sensitivity concentration was between 3.81-5.15 μg/mL, and the inhibition ratio increased with the increase of concentration.ConclusionsDauricine, the main effective component extracted from asiatic moonseed rhizome, had a good inhibition effect on tumor cells in urinary system. At the same time, Dauricine has certain inhibition effects on the primary cultured tumor cell.     

Parasite virulence and disease patterns in Plasmodium falciparum malaria.

Heterogeneity in parasite virulence is one of several factors that have been proposed to contribute to the wide spectrum of disease severity in Plasmodium falciparum malaria. We used observed age-structured patterns of disease to define a population structure of P. falciparum, where the latter contains several independently transmitted antigenic types or "strains" that each induce some degree of strain-specific antidisease immunity upon infection. Patterns of incidence of severe and mild disease may be explained by assuming that a majority of these strains are associated with mild disease and that although severe malarial anemia is a complication occurring in a certain proportion of early infections with "mild" parasites, cerebral malaria is caused by a few distinct highly virulent strains. Considerable variation in parasite virulence, as a major factor of disease severity in malaria, is made possible by the absence of competition between the various parasite strains, arising from weak shared immune responses. The theoretical framework presented in this paper can explain other epidemiological observations, such as the results of interventions with insecticide-impregnated bednets.     

蜂毒素抑制消化道肿瘤生长的研究进展

蜂毒是蜜蜂工蜂毒腺和副腺分泌的透明毒液,民间利用蜂毒治疗类风湿性关节炎已有悠久的历史.蜂毒素是从蜂毒中提取的一种小蛋白分子,具有很强的生物活性.随着现代分子生物科学技术的发展,蜂毒素的提取纯化工艺已成熟,并在体内外实验中取得初步的成果.目前发现蜂毒素具有抗肿瘤作用,且抗肿瘤作用呈多靶点性,可体内外抑制消化道肿瘤的生长,促进肿瘤细胞凋亡,本文就国内外蜂毒素抗消化道肿瘤的机制进展作一概述.     

参麦注射液对LWEIS肺癌小鼠的抗肿瘤及作用机制研究

目的研究参麦注射液对Lweis肺癌小鼠的抗肿瘤作用。方法建立Lweis细胞小鼠移植瘤模型,将荷瘤小鼠随机分为荷瘤对照组,阳性对照组及参麦注射液三个剂量组,另设正常对照组,每日灌胃给药,通过测定抑瘤率,脾脏指数,胸腺指数,TNF-α、Bcl-2、Bax、caspase-9含量,探讨参麦注射液的抗肿瘤作用及作用机制。结果参麦注射液抑制Lweis肺癌小鼠瘤块的生长,降低荷瘤小鼠的脾脏指数,胸腺指数,促进TNF-α,Bax和Caspase-9生成,抑制Bcl-2含量。结论参麦注射液可通过增强荷瘤机体免疫功能及诱导凋亡而发挥抗肿瘤作用。     

Worms and allergy

Worms and asthma are associated with a type 2 immune response, but evidence has accumulated that helminth infection is negatively associated with atopy, prevalence of allergic diseases and severity of asthma. One important difference between these polarized type 2 responses is that in allergy modulation of the immunological response is not appropriate, whereas in infection with helminths, several host mechanisms down-regulate the host immune response. As a result, patients infected with worms have a decrease in both type 1 and type 2 responses. The main mechanism involved in this down-modulation is increased production of IL-10, but expansion of regulatory T cells and NKT cells may also participate. Regarding the interaction between worms and allergy, a few variables need to be taken in account: phase (acute or chronic) of helminth infection, parasite load and species of helminth. In animals and humans, acute helminth infection may increase manifestations of allergy, whereas chronic infection with parasites decreases atopy. The modulation of the immune response by helminths is dependent on having an adequate parasite load. Moreover, although several helminth species have been shown to modulate immune responses, most in vitro and in vivo studies have focused on the importance of Schistosoma mansoni in down-modulating allergic reactions.     

Endogenous glucocorticoids cause thymus atrophy but are protective during acute Trypanosoma cruzi infection

The cytokine-mediated stimulation of the hypothalamus-pituitary-adrenal (HPA) axis is relevant for survival during bacterial endotoxemia and certain viral infections. However, only limited information is available regarding the effects of endogenous glucocorticoids on parasite diseases. We have studied this issue using, as a model, C57Bl/6 and Balb/c mice infected with Trypanosoma cruzi, the causal agent of Chagas' disease. These two mouse strains differ in the susceptibility to infection with the parasite. An intense stimulation of the HPA-axis was observed 3 weeks after infection in both strains, but glucocorticoid levels were already increased two- to threefold in the less susceptible Balb/c strain during the first week. Blockade of glucocorticoid receptors with the glucocorticoid antagonist RU486, starting on day 10 after infection, partially reversed the thymic atrophy and decreased the number of CD4(+)CD8(+) thymocytes without affecting parasitemia and the number of inflammatory foci in the heart. However, tumor necrosis factor-alpha blood levels were increased in infected mice of both strains treated with RU486. Furthermore, the blockade of glucocorticoid receptors accelerated death in C57Bl/6J mice and increased lethality to 100% in Balb/c mice. The results obtained represent the first evidence that an endocrine host response that is coupled to the immune process can strongly affect the course of a parasite infection.     

Induction of tumor immunity and cytotoxic t lymphocyte responses using dendritic cells transduced by adenoviral vectors encoding HBsAg: comparison to protein immunization

Dendritic cells (DC) are specialized antigen-presenting cells with powerful immunostimulatory properties. Their use for induction of anti-tumor immunity has been limited by several factors, including identification of appropriate tumor-associated antigens, delivery of antigens to DC, and maintaining DC in a highly activated state. Here, DC propagated in vitro were transduced with an adenoviral (Ad) vector to express hepatitis B surface antigen (HBsAg), an antigen present in hepatocellular carcinoma (HCC). Many patients with HCC demonstrate evidence of prior HBV exposure, suggesting that the presence of the virus in a quiescent state may promote tumorigenesis. Ad-HBsAg-transduced DC stimulated strong cytotoxic T lymphocyte (CTL) responses to HBsAg-expressing tumor cells, and protected mice from lethal tumor challenge. Immunity was antigen-specific, as wild-type tumor (HBsAg -) grew normally. Furthermore, DC transduced with an irrelevant vector had no effect. Vaccination with HBsAg protein, a clinically utilized preparation that confers immunity to HBV infection, did not protect against tumor challenge even though it induced a strong antibody response. These studies describe for the first time the contributions of humoral and cellular immune responses to tumor immunity induced by Ad-transduced DC compared to protein vaccination.