抗巨噬细胞表面分子Mac-1单克隆抗体对利什曼原虫入侵的抑制作用

目的 :了解抗巨噬细胞表面分子 Mac- 1单克隆抗体 ( M1/70 和 M18/2 )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 ,观察处理后巨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 ,巨噬细胞受染率只有 13.8% ,且受染巨噬细胞内入侵的原虫数量仅有 1- 2个。结论 :M1/70 和 M18/2 可以通过与巨噬细胞表面 Mac- 1的结合 ,分别干扰巨噬细胞表面分子上与利什曼原虫相结合的不同的连接位点 ,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。     

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     

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     

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...     

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。     

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。     

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     

利什曼原虫与巨噬细胞的相互作用及相关抗原

本文对利什曼原虫前鞭毛体表面的巨噬细胞相关抗原的性质，结构，结构，分布状况，种内差异作了综述。并也论及在血清调理和非血清调理环境下，此种抗原与巨噬细胞表面相关受体的作用关系。阐明了利什曼原虫入侵哺乳动物巨噬细胞是确定原虫寄生生活的基础。     

利什曼原虫与巨噬细胞的相互作用及相关抗原

本文对利什曼原虫前鞭毛体表面的巨噬细胞相关抗原的性质、结构、分布状况、种内差异作了综述。并也论及在血清调理和非血清调理环境下,此种抗原与巨噬细胞表面相关受体的作用关系。阐明了利什曼原虫入侵哺乳动物巨噬细胞是确定原虫胞内寄生生活的基础。     

Reactive nitrogen intermediates implicated in the inhibition of Encephalitozoon cuniculi (phylum microspora) replication in murine peritoneal macrophages

Encephalitozoon cuniculi (phylum microspora) is a protozoan parasite that can replicate within parasitophorous vacuoles in macrophages. Thioglycollate-elicited BALBjc peritoneal macrophages treated with murine recombinant interferon-γ (rIFN-γ; 10u/ml) in combination with lipopolysaccharide (LPS; 10ng/ml) for 24 h killed E. cuniculi as determined by significant reductions in the number of parasites and percent of infected macrophages 48 h later compared with cultures treated with medium only. Treatment of the elicited macrophages with murine rIFN-γ (10u/ml or 100u/ml) only, resulted in microbistatic activity. Significantly higher levels of nitrite (NO₂) were detected in supernatants from macrophage cultures treated with rIFN-γ (10 u/ml or 100 u/ml) which induced microbistatic macrophage activity as well as from macrophage cultures treated with LPS + rIFN- when compared with levels of nitrite detected in supernatants of infected macrophages treated with medium only. Addition of the L-ariginine analogue, N³ monomethyl-L-arginine (NMMA) at concentrations of 50, 100 or 250 uM significantly inhibited nitrite synthesis and prevented microsporidia killing. Addition of exogenous L-arginine at concentrations of 5mM or 10 mM reversed the NMMA-induced inhibition of parasite killing. These results indicate that reactive nitrogen intermediates contribute to the killing of E. cuniculi by LPS + rIFN-γ-activated murine peritoneal macrophages in vitro.     

In-vivo treatment with benznidazole enhances phagocytosis, parasite destruction and cytokine release by macrophages during infection with a drug-susceptible but not with a derived drug-resistant Trypansoma cruzi population

To stuck the effect of chemotherapy on parasite-macrophage interaction we used the wild-type Y strain (drug-susceptible) of Trypanosoma cruzi and a drug-resistant parasite population derived from the same strain. Trypomastigotes isolated from untreated infected mice, as well as, 3 h after treatment with BZ were incubated with inflammatory macrophages and used to study phagocytosis, parasite destruction, cytokine release and reactive nitrogen intermediates (RN!) synthesis. Phagocytosis and destruction of the drug-susceptible parasites were significant/v enhanced by drug treatment. These enhancements were accompanied by an increase in cytokines [interleukin (IL)-12 and tumour necrosis factor (TNF)alpha] and RNI release by murine inflammatory macrophages primed with IFN-gamma. In contrast, BZ treatment of mice infected with drug-resistant T. cruzi population showed no effect whatsoever. The synthesis of IFN-gamma and RNI by splenocytes of mice infected with either susceptible and drug-resistant parasite populations, before and after treatment with BZ were also studied. On/v the splenocytes from mice infected with the drug-susceptible parasites treated with BZ produced high levels of IFN-gamma and RNI. Our findings indicate that BZ acts on the drug-susceptible T. cruzi parasites by enhancing the phagocytosis and the production of cytokines and RN!, thus, favouring the destruction of the intracellular parasites by the cellular compartment of the immune system.     

Ultrastructural studies on the in vitro interaction of Trypanosoma cruzi bloodstream forms and mouse peritoneal macrophages

Macrophages are normally host cells for T. cruzi in the vertebrate host. Since the process of interiorization of this parasite into those cells is still controversial, we decided to investigate by electron microscopy the in vitro uptake of T. cruzi bloodstream forms by mouse peritoneal macrophages. After 15 min of interaction with macrophages, parasites are interiorized by a process of phagocytosis in which both parasite and host cell seem to play a specific role. Sequential steps of the uptake process and the simultaneous ultrastructural alterations of the host cell morphology have been studied. A dense amorphous substance interposed between the parasite and the macrophage surface was regularly observed. Although its origin, significance and nature remain unknown, we discuss the possibility that it might be released extracellularly by the macrophage in response to the parasite stimulation.     

Post lung-stage schistosomula of Schistosoma mansoni exhibit transient susceptibility to macrophage-mediated cytotoxicity in vitro that may relate to late phase killing in vivo

Studies of protective immunity against Schistosoma mansoni in immunized mice suggest that a proportion of challenge parasites may be eliminated after they have passed through the lungs of the host several days after infection; however, no potential immune effector mechanism of resistance against this stage of the parasite has yet been identified, since schistosomes have been shown to rapidly become resistant to antibody-dependent killing mechanisms. In this study, different development stages of S. mansoni were examined for their susceptibility to in vitro cytotoxicity by lymphokine-activated macrophages. As previously shown, newly transformed larvae were readily killed by lymphokine-treated peritoneal macrophages or the macrophage cell line IC-21 (80% mortality over 48 h in vitro), whereas 7 and 10 day old lung-stage parasites had become refractory to macrophage effects. However, after 2 to 2 1/2 weeks of development in vivo, juvenile parasites recovered from the liver were again susceptible to activated macrophage-mediated cytotoxicity (25-65% mortality). Ultrastructural studies of 2 1/2 week old parasites co-cultured with activated IC-21 cells revealed that damage was largely restricted to the areas beneath the parasite surface and gut syncitia; surface membrane disruption was not evident. This late stage of susceptibility was transient and by 4 to 6 weeks liver-stage worms had again become refractory to macrophage killing. The interaction of post lung-stage parasites with activated macrophages was antibody independent. Furthermore, schistosomes isolated from the portal circulation 2 1/2 weeks after infection showed no evidence of surface-bound immunoglobulin in a quantitative immunofluorescence assay, nor did antisera from chronically infected mice (CIS) or mice vaccinated with irradiated cercariae (VS) react with the surface of these parasites in vitro, making the possibility of direct antibody-dependent killing mechanisms unlikely. However, both CIS and VS did recognize excretory/secretory proteins synthesized by 2 1/2 week old liver-stage schistosomes, including a major antigen of approximate Mr (X 10(-3] 220 (220K). It is therefore possible that such antigens might participate in protective immunity, for example via immune complex formation or activation of sensitized T cells. These observations support the role of macrophages as immune effector cells in mice immunized against Schistosoma mansoni, and provide the first physiologically relevant mechanism whereby the immune system might recognize and kill post-lung stage schistosomes.     

Studies on intracellular killing of Leishmania major and lysis of host macrophages by immune lymphoid cells in vitro

Exposure of Leishmania major-infected CBA/T6 mouse macrophages to lymph node cells (LNC) from infected animals led to antigen-specific killing of the micro-organisms. The effect depended on the number of added LNC, the duration of incubation with macrophages, and the presence of LPS in the incubation fluids. Incubation with immune LNC also resulted in lysis of part of the infected cells, however without release of live amastigotes, as parasites were destroyed intracellularly before macrophages were damaged. Supernates from antigen-stimulated LNC cultures activated macrophages for intracellular killing without damage to the host cells, suggesting that macrophage lysis was not a consequence of the activation process. Treatment of effector lymphocytes with anti-L3T4 antibodies abrogated both intracellular killing and macrophage lysis. Parasitized macrophages were also destroyed by alloimmune cytolytic T-lymphocytes; in this case, however, live amastigotes were released, showing that immune lysis of the infected cells would not entail parasite destruction per se. These studies support the hypothesis that recovery from L. major infection relates to the ability of lymphoid cells to generate MAF/IFN in response to parasite antigen and are compatible with the idea that lysis of parasitized macrophages may contribute to immune recovery from the infection.     

Interaction of bloodstream, tissue culture-derived and axenic culture-derived trypomastigotes of Trypanosoma cruzi with macrophages

Mouse macrophages were infected with bloodstream, tissue culture-derived and axenic culture-derived trypomastigotes of the Y and the CL strains of Trypanosoma cruzi. The percentage of infected cells, the mean number of parasites per cell and the incorporation index were determined after 2 h of interaction. Longer periods of interaction were used to evaluate the fate of the different trypomastigotes inside the macrophage. It was observed that the incorporation of T. cruzi by the macrophages was high for tissue culture-derived trypomastigotes, intermediate for axenic culture-derived trypomastigotes and low for bloodstream trypomastigotes. For the three types of trypomastigotes, a larger number of macrophages were infected with parasites from the Y than the CL strain. These results suggest that the ability to infect macrophages is a basic characteristic of each strain which is maintained when the parasites are transferred from the vertebrate of the invertebrate host to in vitro systems.     

Investigations on the in vitro metacyclogenesis of a visceral and a cutaneous human strain of Leishmania infantum

The in vitro metacyclogenesis of a visceral (VL) and cutaneous (CL) human strain of Leishmania infantum was monitored in order to find out the kinetics of this process and the in vitro infective capacity for macrophages of the metacyclic promastigotes developed. To identify, enumerate, and separate the metacyclic population, the complement-dependent lysis by normal serum and the agglutination by peanut agglutinin (PNA) were used, as they were shown to be useful for the purpose of this study. Maximum percentage of metacyclics was detected by both techniques on the 4th day of growth for VL and the 6th day for CL, and was higher for the VL strain. The in vitro infectivity for macrophages of two strains was assayed, and the high parasitization data obtained were transformed in order to determine the increase of the parasite burden for macrophages throughout the incubation time of the experiments (2–72 h post-infection (p.i.)). This parameter is denominated the infectivity ratio (%I) and calculated as follows: (number of intracellular parasites per infected macrophage at ‘x' time p.i./number of intracellular parasites per infected macrophage at 2 h p.i.)×100. When %I was calculated for promastigotes unagglutinated by PNA (PNA−)—metacyclic or infective promastigotes—at any time of culture, the %I at 72 h p.i. was always much higher than for agglutinated promastigotes (2.1–12.5 times)—non-infective promastigotes—and unfractionated promastigotes from culture (1.7–9.5 times), especially with VL parasites. Likewise, the %I for VL PNA− promastigotes from the 4th day of culture was 1.9 times higher than for CL PNA− promastigotes from the 6th day of culture. The higher resistance to lysis by serum, percentage of metacyclics (PNA−), and infectivity ratio of VL than CL could be related to a higher spreading capability into the host body associated with higher pathogenic effects of the visceral strain than the cutaneous one.     

肿瘤坏死因子增强巨噬细胞杀伤约氏疟原虫的观察

目的 :观察肿瘤坏死因子 ( TNF)对巨噬细胞 ( MΦ)表面受体表达及吞噬功能的影响 ,探讨 TNF体内杀伤疟原虫机制。方法 :以感染约氏疟原虫的 BAL B/ c小鼠为动物模型 ,将不同浓度的 TNF与小鼠腹腔 MΦ体外培养 5h后 ,加入感染红细胞 ,观察 MΦ对感染红细胞的吞噬率 ,将 TNF作用后的 MΦ用 m PAP超微半定量法测定 Fc受体 ,YC花环法测定 C3b受体。结果 :TNF能够增加 MΦ 对感染红细胞的吞噬率 ,其作用与 TNF剂量呈正相关。TNF可增加正常及感染鼠MΦ 表面 Fc受体和 C3b受体的表达。结论 :TNF在感染小鼠体内可能调节 MΦ 表面受体的表达并增加其吞噬疟原虫的功能     

Tissue eosinophilia and Leishmania mexicana mexicana eosinophil interactions in murine cutaneous leishmaniasis

Summary Outbred albino mice were infected subcutaneously with 10⁶ amastigotes of Leishmania mexicana mexicana and the subsequent lesions were evaluated by light and electron microscopy at various intervals after infection. The animals developed persistent nodules and a spectrum of lesions of variable size which was correlated with the host's ability to control the parasite in the tissue. During the acute phase of the disease the histopathological results showed an accumulation of granulocytes, some mononuclear phagocytes and a predominance of eosinophils as compared to other cell types. In this early acute phase, eosinophils were found in the tissue together with normal and degranulating mast cells. In the granulomatous inflammatory reaction of the chronic phases, there was infiltration of granulocytes parallel to parasite multiplication and the formation of parasitized vacuolated macrophages. The number of eosinophils was consistently greater than neutrophils, regardless of lesion type or number of parasites present in the tissue. During the acute reaction, the granulocytes apparently destroyed many parasites; however, there was an unvaryingly low level of phagocytosis of amastigotes during the chronic stages by both eosinophils and neutrophils. Neutrophils seemed to be more effective than eosinophils in the killing of ingested parasites. A close association between eosinophils and parasitized macrophages was seen in the chronic lesions; thus, eosinophils might contribute to parasite destruction through co-operation with macrophages.