抗巨噬细胞表面分子Mac-1单克隆抗体对利什曼原虫入侵巨噬细胞的抑制作用

应用抗巨噬细胞表面分子Mac-1单克隆抗体（M1／70和M18／2）处理巨噬细胞，观察M1／70和M18／2对杜氏利曼原虫前鞭毛体入侵巨噬细胞的抑制作用。结果，经上述单抗处理后巨噬细胞，对杜氏利什曼原虫的易感性明显降低，其原虫感染率和受染巨噬细胞内入侵的原虫数量减低，原虫对巨噬细胞的入侵过程及速度也减慢。M1／70和M18／2两种单抗同时应用，则对原虫侵入巨噬细胞的抑制作用更为显著，巨噬细胞受染率为13．8％，且受染巨噬细胞内入侵的原虫数量大多仅有1～2个。提示，M1／70和M18／2单克隆抗体可以通过与巨噬细胞表面Mac－1的结合，干扰巨噬细胞表面分子上与利什曼原虫相结合的连接位点，抑制利什曼原虫对巨噬细胞的入侵。     

抗巨噬细胞表面分子Mac—1单克隆抗体对利什曼…

目的：了解抗巨噬细胞表面分子Ｍａｃ－１克隆抗体对杜氏利什曼原虫入侵巨噬细胞的抑制作用。方法：应用Ｍ１／７０和Ｍ１８／２处理巨噬细胞，观察处理后居噬细胞对杜氏利什曼原虫前鞭毛体的易感性，结果：巨噬细胞经上述单抗处理后，其原虫感染率和受染巨噬细胞内入侵的原虫数量明显降低，原虫对巨噬细胞的入侵过程及速度减慢，Ｍ１／７０和Ｍ１８／２两种单抗同时应用，则对原虫侵入巨噬细胞的抑制作用更为显著，巨噬细胞受染率中     

抗巨噬细胞表面分子Mac—1单克隆抗体对利什曼原虫入侵巨噬细胞的…

应用抗巨噬细胞表面分子Ｍａｃ－１单克隆抗体处理巨噬细胞，观察Ｍ１／７０和Ｍ１８／２对杜氏利曼原虫前鞭毛体入侵巨噬细胞的抑制作用。结果，经上述单抗处理后巨噬细胞，对杜氏利什曼原虫的易感性明显降低，其原虫感染率和受染巨呼工细胞内入侵的原虫数量减少低，原虫对巨噬细胞的入侵过程及速度也减慢。     

经胰蛋白酶消化后杜氏利什曼原虫前鞭毛体表膜肝素受体的恢复

已发现杜氏利什曼原虫前鞭毛体表面具有特异性肝素受体,推测该受体在杜氏利什曼原虫与巨噬细胞间起分子连接作用。本文介绍以实验方法探讨胰蛋白酶处理后原虫表面肝素受体的恢复情况。     

利什曼原虫ICAM-L分子阻止巨噬细胞从细胞周期G1过渡到S阶段

利什曼原虫专一寄生于宿主的巨噬细胞内,通过受体介导的吞噬作用感染巨噬细胞。最近,用感染杜氏利什曼原虫的巨噬细胞cDNA微阵列分析所得到的分布图显示,37%的巨噬细胞基因表达下调,这其中包括一组细胞周期蛋白依赖的激酶抑制因子(CKIs)。细胞分裂依赖于细胞周期蛋白依赖的激酶(CDKs)诱导细胞周期向S阶段过渡,随后启动了有丝分裂。在正常的情况下,CDKs的功能受细胞周期抑制因子如p21、p27蛋白周密调节,而未受控制的CDKs的活性经常导致肿瘤发生。在利什曼原虫感染期间,一些巨噬细胞基因可以吸引更多的巨噬细胞至感染部位。至今尚无任何单一的机制或因子被确定可以解释利什曼原虫感染期间巨噬细胞的活化或失活。Kuzmenok等最近从亚马孙利什曼原虫克隆了一个细胞内黏附分子样(ICAM-L)表面分子,该分子属于免疫球蛋白超家族。重组的ICAM-L蛋白被能抑制利什曼原虫对宿主巨噬细胞的黏附,表明该蛋白是巨噬细胞表面受体的识别分子。该基因仅存在于利什曼原虫。Kuzmenok等就ICAM-L对巨噬细胞细胞周期的调节作用进行了探讨。在MTT试验中,用ICAM-L蛋白和2个巨噬细胞系J774G8、RAW264.7共同孵育比用M2蛋...     

雄性激素抑制感染杜氏利什曼原虫的巨噬细胞的凋亡

目的：研究雄性激素对Ｃ５７ＢＬ／６ｊ雌性小鼠骨髓巨噬细胞凋亡的影响。方法：溴化丙锭染色及透射电镜观察凋亡特征性形态学变化。来自雄性激素和油处理过的小鼠骨髓巨噬细胞分别用杜氏利什曼原虫（Ｌｅｉｓｈｍａｎｉａｄｏｎｏｖａｎｉ）攻击２４ｈ后,检测特征性的ＤＮＡ凋亡梯形。结果：在培养基中去掉Ｍ－ＣＳＦ后可以诱导骨髓巨噬细胞的凋亡。ＤＮＡ片段电泳提示：①在雄性激素和油处理组间凋亡细胞的量没有区别,然而②经杜氏利什曼原虫攻击后,雄性激素处理组的凋亡细胞数明显低于油处理组。结论：雄性激素可以抑制感染了杜氏利什曼原虫的巨噬细胞的凋亡,不感染利什曼原虫时,这种抑制作用并不出现。雄性激素对骨髓巨噬细胞凋亡的抑制作用可能在雄性激素诱导的免疫抑制作用中发挥着重要的作用     

TESTOSTERONE INHIBITS APOPTOSIS OF LEISHMANIA DONOVANI INFECTED MACROPHAGES*

目的：研究雄性激素对Ｃ５７ＢＬ／６ｊ雌性小鼠骨髓巨噬细胞凋亡的影响。方法：溴化丙锭染色及透射电镜观察凋亡特征性形态学变化。来自雄性激素和油处理过的小鼠骨髓巨噬细胞分别用杜氏利什曼原虫（Ｌｅｉｓｈｍａｎｉａｄｏｎｏｖａｎｉ）攻击２４ｈ后,检测特征性的ＤＮＡ凋亡梯形。结果：在培养基中去掉Ｍ－ＣＳＦ后可以诱导骨髓巨噬细胞的凋亡。ＤＮＡ片段电泳提示：①在雄性激素和油处理组间凋亡细胞的量没有区别,然而②经杜氏利什曼原虫攻击后,雄性激素处理组的凋亡细胞数明显低于油处理组。结论：雄性激素可以抑制感染了杜氏利什曼原虫的巨噬细胞的凋亡,不感染利什曼原虫时,这种抑制作用并不出现。雄性激素对骨髓巨噬细胞凋亡的抑制作用可能在雄性激素诱导的免疫抑制作用中发挥着重要的作用     

免疫小鼠腹腔巨噬细胞对杜氏利什曼原虫感染的反应

小鼠腹腔巨噬细胞能够支持杜氏利什曼原虫的生长、繁殖和转化。本文进一步观察了免疫小鼠的腹腔巨噬细胞对利什曼感染的反应以及淋巴因子对感染过程的影响。 材料与方法:1.杜氏利什曼原虫785株,系1978年从喀什地区一例黑热病人骨髓中分离,在感染仓鼠中传代保存;2.实验动物及免疫方法:取三周龄     

杜氏利什曼原虫动基体DNA种林特异片段的克隆

作者在质粒pUC18中克隆了限制性内切酶AIuI消化的Leishmania donovani四川人分离株kDNA片段,筛选后获得能区别杜氏利什曼原虫山丘疫区分离株和平原疫区分离株的的克隆pLK1-10和对杜氏利什曼原虫四川人分离株特异的克隆pLK1-14,对杜氏利什曼原虫种特异的克隆PLK1-1、pLK1-2等。这些克隆将是鉴定杜氏利什曼原虫,区别鉴定山丘及平原疫区黑热病病原体较好的探针。     

杜氏利什曼原虫23kDa抗原编码基因克隆的表达

将已建立的杜氏利什曼原虫 c DNA文库基因 ,亚克隆于 p UC18质粒载体 ,诱导表达筛选两个克隆 ,即 P1、P2 ,表达的蛋白分子量皆为 2 3k Da,P1克隆表达的 2 3k Da蛋白分子 ,经 Western blot分析显示 ,可被兔抗杜氏利什曼原虫前鞭毛体抗血清及内脏利什曼病病人血清识别     

Photoinactivation of Leishmania donovani infantum in red cell suspensions by a flexible thiopyrylium sensitizer

BACKGROUND AND OBJECTIVES: Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania, which are intracellular parasites of monocytes and macrophages. Transmission of the organism has been observed by transfusion of infected blood from asymptomatic donors to immunocompromised recipients, leading to clinically apparent disease. There is no licensed Leishmania screening test currently available. MATERIALS AND METHODS: This study investigated the potential for a novel DNA-intercalating photosensitizer, thiopyrylium (TP), to inactivate Leishmania donovani infantum in red cell (RBC) suspensions. RESULTS: A 5.7 TCID50 reduction of Leishmania was observed in samples treated with 12.5 micromole l(-1) TP and 1.1 J cm(-2) light. CONCLUSIONS: Leishmania is highly sensitive to photoinactivation under conditions that have been previously demonstrated to maintain RBC properties during 42 days of storage.     

雄性激素对小鼠骨髓巨噬细胞杜氏利什曼原虫感染水平的影响

目的：研究雄性激素对杜氏利什曼原虫感染的C57BL／6J小鼠骨髓巨噬细胞（BMMs）水平的影响。方法：用雄性激素处理小鼠3wk后，收集BMMs，培养5d后，按BMMs前鞭毛体＝110的比例，接种杜氏利什曼原虫，用吉姬氏染色法观察不同时相的感染水平。结果：与植物油处理的对照组相比，雄性激素处理的小鼠BMMs对前鞭毛体较为易感，并随着感染时间的延长其感染水平增高（感染后3h，P＜0．05；24h，48h和72h，P＜0．01）。结论：雄性激素可增加杜氏利什曼原虫对BMMs 的感染水平, 这可能与雄性激素诱导的免疫抑制作用有关。     

Efficacy of Trypan: a diminazene based drug as antileishmanial agent

Trypan, a diamidine based drug, was tested as an antileishmanial agent. Duplicate cultures of both Leishmania major and Leishmania donovani promastigotes in M199 medium and Trypan at various concentrations were tested. The cultures were incubated at 25 degrees C and parasites counted at 48 h interval, and the data generated was used to establish growth inhibition curves. Drug-free cultures were included to serve as control. In the in vivo study, a total of 40 BALB/c mice were divided into five groups of 8 mice each. They were infected with 2 x 10(6) promastogotes on the left footpad. Two groups were treated with 70 microg/ml of Trypan, a total of 500 microl used immediately after infection, one group by topical application and the other administered intraperitoneally. The treatments were repeated for the two other groups 10 weeks post infection, one by topical application and the other administered intraperitoneally. One group was not treated and thus served as control. Footpad sizes were measured using Vernier calliper every 2 weeks for 21 weeks. In the in vitro studies, Trypan inhibited growth of either L. major or L. donovani promastigotes in all the concentrations tested with more dramatic inhibition in high concentrations. Based on the in vivo studies, it was evident that Trypan had effect on L. major infected lesions when applied topically immediately after infection. However, there was no effect when treatment commenced after the lesions were established. The data is discussed.     

Granulocyte-macrophage and macrophage colony-stimulating factors activate intramacrophage killing of Leishmania mexicana amazonensis

Leishmania organisms are important pathogens, causing diseases worldwide. Standard therapies are often toxic and are not always effective. The effect of recombinant human granulocyte-macrophage and macrophage colony-stimulating factors (GM-CSF and M-CSF) on intramacrophage survival of Leishmania mexicana amazonensis (Lma) were compared with those of interferon-gamma (IFN-gamma). Macrophages previously infected with Lma were treated with or without GM-CSF and M-CSF. Compared with no cytokine treatment, treatment with GM-CSF (0.1-100 ng/ml) or M-CSF (1:3.5 X 10(6) - 1:3.5 X 10(3) dilutions) caused a significant dose-dependent reduction in intracellular parasites, 427 +/- 20 (mean +/- SE) Lma/100 macrophages. GM-CSF or M-CSF in combination with IFN-gamma resulted in more effective inhibition of intracellular parasites. Thus, the cytostatic activity appears to require interaction between cytokines, macrophages, and amastigotes. These cytokines are potential therapeutic agents for visceral leishmaniasis.     

Intracellular survival of Leishmania species that cause visceral leishmaniasis is significantly reduced by HIV-1 protease inhibitors

Visceral leishmaniasis is now recognized as an opportunistic disease in individuals infected with human immunodeficiency virus type 1 (HIV-1). Although the usefulness of HIV-1 protease inhibitors (PIs) in antiretroviral regimens is well documented, little is known about their potential impact in the setting of Leishmania/HIV-1 coinfections. We now report that, although selected PIs do not inhibit the growth of Leishmania infantum promastigotes alone in culture, these drugs significantly inhibit the intracellular survival of parasites in phorbol myristate acetate-differentiated THP-1 macrophages and human primary monocyte-derived macrophages (MDMs). Furthermore, a field isolate of Leishmania donovani resistant to sodium stibogluconate (SbV), one of the drugs most commonly used to treat leishmaniasis, is equally susceptible to the tested PIs compared with a sensitive strain, thus suggesting that resistance to SbV does not result in cross-resistance to PIs. Importantly, the efficacy of PIs to reduce the intracellular growth of Leishmania parasites is also observed in MDMs coinfected with HIV-1.     

Leishmania parasites and their ploys to disrupt macrophage activation

Leishmania are intracellular protozoan parasites of macrophages. At the cellular level, the disease leishmaniasis involves the invasion of tissue macrophages by the parasite, the avoidance of cellular killing mechanisms, and the subsequent intracellular replication of parasites, with the eventual spread of the organisms to adjacent macrophages. This paper describes the process by which Leishmania organisms invade macrophages, with an overview of some of the molecules involved in this process; the mechanisms available to macrophages that have the potential to restrict the growth of Leishmania within them; and the ways that Leishmania and Leishmania-derived molecules can modulate macrophage functions and circumvent leukocyte antimicrobial responses.     

Studies on the effect of the anti-phagocytic agent cytochalasin B on Leishmania-macrophage interaction.

Mouse peritoneal exudate cells were cultured on coverslips in Eagle's Basal Essential Medium. The adhering cells were infected with promastigotes of three different species of Leishmania. After 8 h incubation, the macrophages were fixed and stained, and a total of one hundred cells were counted. The rates of infection of macrophages were respectively 53.5 +/- 5% for L. enriettii, 52.3 +/- 5% for L. donovani and 11.7 +/- 2% for L. tropica. When cytochalasin B at concentrations of 2.5, 5 and 10 microgram/ml and Leishmania promastigotes were added to the adhering cells at the same time, the drug did not have any effect on the uptake of the organisms by the macrophages. However, when the cells were treated for a 2-h period with the drug and then were infected with the promastigotes, only 1-2% of the cells were infected. On the other hand, when cytochalasin B-treated cells which had lost their phagocytic ability were washed and then were infected with the promastigotes, some degree of cellular infection was observed. It was concluded that infection of mouse p.e.c. by three different species of Leishmania which were used in our study was by phagocytosis rather than active penetration of the organisms into the cells. It was also of interest to note that although our outbred strain of mice gets infected easily with L. tropica, the p.e.c. of these animals phagocytosed L. tropica with least efficiency in comparison with L. donovani and L. enriettii.     

Antileishmanial drugs cause up-regulation of interferon-gamma receptor 1, not only in the monocytes of visceral leishmaniasis cases but also in cultured THP1 cells

Apparently for the first time, the peripheral blood monocytes of individuals with active visceral leishmaniasis (VL) have been found to show reduced expression of interferon gamma receptor-1 (IFNGR1). Since interferon gamma is the main cytokine responsible for defence against leishmanial parasites, it was thought possible that effective antileishmanial drugs may up-regulate IFNGR1. Confocal microscopy confirmed that monocytes from VL patients who had been treated, with sodium antimony gluconate (SAG), did display IFNGR1 up-regulation. To see if this effect could be mimicked in vitro, IFNGR1 expression was investigated using a human macrophage cell line (THP1), northern blotting and confocal microscopy. When the THP1 cells were treated with SAG or pentamidine, their expression of the receptor was increased. This drug-induced up-regulation was more intense if the macrophages were infected with Leishmania donovani than if they were left uninfected. The possibility that at least some antileishmanial drugs act by up-regulating IFNGR1 expression needs to be explored further. A good model for investigating the mechanisms of action of antileishmanial drugs might be based on the THP1 cell line.