小鼠中性粒细胞在抗体及补体参与下对日本血吸虫童虫杀伤作用的体…

用光镜及电镜观察小鼠中性粒细胞及中性粒细胞依赖抗体及补体对体外培养的日本血吸虫童虫的作用。结果表明,单纯中性粒细胞很少粘附到童虫表面,仅个别发疏松地粘附在童虫表面,被粘附的童虫结构正常,提示：单纯中性粒细胞对童虫无明显作用,在抗体及补体协同下,中性粒细胞成群且紧密地粘附在童虫体表,在细胞集聚的周围,虫体体被出现隧道样及火山口样变化,紧贴童虫的中性粒细胞伸出伪足,虫体体棘紊乱,皮层变平,体被剥脱,虫     

免疫血清及补体对体外培养日本血吸虫童虫的杀伤作用

本文报道抗体、补体、补体加抗体对机械转变日本血吸虫童虫的杀伤作用,并比较其杀伤效率。用光学显微镜及扫描电镜观察形态变化。结果显示杀伤率为补体加抗体>单纯补体>单纯抗体。除去补体血清中的B因子,杀伤率明显下降,说明补体C_3旁路途径参与杀伤童虫的作用。童虫孵育于含有补体及抗体的培养基中72h后,虫体头背部体棘零乱或消失,有些体被破损及脱皮。     

日本血吸虫肝门型童虫扫描电镜观察

1.本文报道用扫描电镜观察正常情况下日本血吸虫10日龄和15日龄肝门型童虫体被超微结构,可供血吸虫免疫学、药理学和生理学研究参考。 2.根据肝门型童虫的大小、形状、皮式等错综复杂的表现,认为童虫皮式,不仅在同龄而且在同一个体不同部位,其演变是不同步的。 3.对本型童虫与日本血吸虫成虫有关资料如皮褶、体棘和感觉乳突等方面作了比较。     

磷脂酶A2激活对中性粒细胞趋化和粘附的作用

外源性磷脂酶A2(Ⅰ型PLA2)和钙离子载体(A23187)可明显促进中性粒细胞对TNF,FMLP的趋化及同玻璃球的粘附.PLA2抑制剂二溴苯乙酮(PBPB)和PLA2抗体对PLA2诱发的趋化和粘附具有浓度相关的抑制作用,而对A23187的相同作用并无影响.提示PBPB和PLA2抗体可能通过直接同PLA2作用而抑制PMN趋化和粘附,A23187诱导的促趋化及粘附作用可能不同于PLA2.     

细胞粘附分子在中性粒细胞介导的缺氧／复氧心肌细胞损伤中的作用

目的观察缺氧/复氧对心肌细胞与中性粒细胞粘附效应的影响及细胞间粘附分子-1(intercellularadhensionmolecule-1,ICAM-1)和淋巴细胞功能相关抗原-1(lymphocytefunctionassociatedantigen-1,LFA-1)在中性粒细胞介导的心肌细胞损伤的作用。方法计数不同实验条件下与心肌细胞粘附的中性粒细胞;以及抗ICAM-1单抗和抗LFA-1单抗阻断后中性粒细胞粘附数的改变,检测心肌细胞乳酸脱氢酶释放量。结果中性粒细胞与缺氧/复氧心肌细胞粘附数较缺氧组和正常对照组显著增加(P＜0.01);心肌细胞释放LDH明显增高(P＜0．01),单纯缺氧组与正常对照组相比无显著差异(P＞0．05)。加入抗ICAM-1单抗和抗LFA-1单抗后,缺氧/复氧组与心肌细胞粘附的中性粒细胞数较正常对照组显著降低(P<0．01),心肌细胞释放LDH也明显下降(P＜0．01)。缺氧组与正常对照组相比则无显著差异(P＞0.05)。结论缺氧/复氧使心肌细胞与中性粒细胞粘附效应增加,心肌细胞损伤加重,ICAM-1和LFA-1参与这一过程。抗ICAM-1和抗LFA-1单抗可减轻中性粒细胞对缺氧/复氧心肌细胞的损伤。     

原位杂交检测斯氏肺吸虫童虫半胱氨酸蛋白酶的基因表达部位

目的 从基因水平研究半胱氨酸蛋白酶基因在斯氏肺吸虫童虫的表达,并进行虫体定位。方法 利用地高辛标记原位杂交技术检测半胱氨酸蛋白酶基因在斯氏肺吸虫童虫的表达并定位。结果 在斯氏肺吸虫童虫的肠管上皮细胞中呈强阳性着色,在虫体皮层细胞中有弱阳性着色。结论 半胱氨酸蛋白酶主要在斯氏肺吸虫童虫的肠管上皮细胞中表达,在虫体皮层细胞中也有弱表达。     

人中性粒细胞C_3受体YC玫瑰花结形成及其形态学观察

异物被吞噬细胞吞噬时通常需要经过细胞膜上受体的认别和粘附。大量实验证明,无论是中性粒细胞还是巨噬细胞,其细胞表面均存在有Fe受体和C_3补体受体,它们在吞噬细胞识别、结合、吞噬抗原颗粒及传递抗原信息中起着协同作用。体内外各种因子或微环境均能影响表面补体受体的活性。     

缺氧—再给氧刺激培养的脑微血管内皮细胞表达细胞间粘附分子—1

在缺氧－再给氧条件下,观察了体外分离培养的大鼠脑微血管内皮细胞表面粘附分子ＩＣＡＭ－１的表达及中性粒细胞与内皮细胞粘附作用的改变。结果表明,单纯缺氧１０ｈ不引起内皮细胞ＩＣＡＭ－１的上调,再给氧６ｈＩ－ＣＡＭ－１的表达升高（Ｐ＜０．０１）,再给氧１２ｈ表达量增加了１００％（Ｐ＜０．０１）,此时中性粒细胞与内皮细胞的粘附作用也明显增强（Ｐ＜０．０１）。缺氧前用盐酸川芎嗪（２ｍｇ／ｍｌ）预处理内皮细胞可阻断ＩＣＡＭ－１的表达（Ｐ＜０．０１）,同时也可降低ＰＭＮ与内皮细胞的粘附（Ｐ＜０．０５）。结果提示,脑微血管内皮细胞在缺氧－再给氧刺激下可自身调节Ｉ－ＣＡＭ－１的表达,为中性粒细胞与内皮细胞的粘附提供特异的结合位点。     

健康人群及某些疾病红细胞C_3d受体活性的观察

近年来,红细胞对机体免疫功能的作用日益受到人们的重视。证明红细胞表面的C_3b受体能与循环系统中的抗原—抗体—补体复合物粘附在一起。这种免疫粘附作用(RCIA)不但可能使循环复合物得到清除。而且T细胞区亦得以依赖反应等。     

强壮粗体虫寄生引起的鳜肠道病理

强壮粗体虫是鳜肠道最常见寄生蠕虫。通过光镜及电镜对自然感染强壮粗体虫的鳜肠道进行了组织病理观察。强壮粗体虫的寄生引起鳜肠上皮细胞脱落、肠固有膜层结缔组织增生及白细胞向病灶处浸润,并可观察到嗜酸性粒细胞附着在与肠上皮及固有膜接触的虫体的体壁及吻部。在虫体吻部与肠固有膜层接触处依次观察到纤维细胞、成纤维细胞、嗜酸性粒细胞等,其中嗜酸性粒细胞又可分为未成熟嗜酸性粒细胞、成熟的嗜酸性粒细胞及正在脱颗粒的嗜酸性粒细胞。另外在肠壁的固有膜层观察到包裹虫体的结缔组织纤维囊,囊壁由三层结构构成,同时在鳜肠壁相同的位置观察到被宿主细胞浸润了的组织空腔,推测其为结缔组织纤维囊退化所形成       

Antibody-dependent killing of Schistosoma mansoni schistosomula in vitro by starch-elicited murine macrophages. Critical role of the cell surface integrin Mac-1 in killing mediated by the anti-Mr 16,000 mAb B3A

Starch-elicited murine peritoneal macrophages were able to kill schistosomula in vitro in the presence of a variety of immune sera. Dose response experiments revealed the superior "quality" of serum from mice vaccinated four times with highly irradiated cercariae (4xVMS) in mediating killing at titers comparable to the other sera tested. B3A, a partially protective mAb (IgG3) that recognizes a Mr 16,000 schistosomular surface Ag, mediated higher levels of killing than any of the sera at comparable titers. In contrast, H12, a partially protective mAb (IgG2a; anti-Mr 32,000), and C1C9, a nonprotective McAb (IgG3; anti-Mr 38,000) failed to mediate killing. Two anti-Mac-1 alpha-chain mAb (5C6 and M1/70) mediated substantial dose-dependent blocking of 4xVMS and B3A-mediated macrophage killing. In contrast, a mAb to the Mac-1-associated beta-chain was less effective, whereas the mAb F4/80 did not significantly block killing despite being present on this macrophage population. Although whole 5C6 Ig was the most efficient at inhibiting B3A-mediated killing, 5C6 Fab fragments were still effective at concentrations as low as 0.5 microgram/ml (10 nM). On a molar basis 5C6 appeared to be more effective at blocking 4xVMS-mediated killing than M1/70, while only M1/70 was capable of inhibiting macrophage adherence to schistosomula. These findings, together with the observation that anti-alpha chain mAb were far more effective at blocking killing than the anti-beta-chain mAb, rules out the possibility that 5C6 is nonspecifically inhibiting B3A-FcR interaction. The data also imply a functional relationship between Mac-1 and FcRIII, the receptor for B3A, in macrophage killing.     

IL-10 synergizes with IL-4 and transforming growth factor-beta to inhibit macrophage cytotoxic activity.

After activation with IFN-gamma, thioglycollate-elicited murine peritoneal macrophages kill schistosomula of Schistosoma mansoni in vitro by an L-arginine-dependent mechanism which involves the production of reactive nitrogen oxides (NO). In the present study we demonstrate that the regulatory cytokines IL-10, IL-4, and transforming growth factor-beta (TGF-beta) are potent inhibitors of this extracellular killing function of activated macrophages. Each cytokine was found to suppress killing of schistosomula in a dose-dependent fashion. The activity of IL-10 was not permanent, because subsequent treatment with additional IFN-gamma 2 to 6 h later reversed the inhibition of macrophage larval killing. More importantly, the combination of suboptimal levels of any two of these three cytokines was found to give a potent synergistic suppression of schistosomulum killing by IFN-gamma-treated macrophages. Similarly, IL-10, IL-4, or TGF-beta alone blocked the production of NO, and when used in combination these cytokines exhibited an enhanced inhibitory effect on nitrite production. Macrophage-mediated killing of schistosomula through the generation of NO has been shown previously to be a major effector mechanism of schistosome immunity. The results presented here suggest that the suppression of this mechanism by induction of the regulatory cytokines IL-10, IL-4, and TGF-beta, which are known to be produced during schistosome infection, may be an important strategy used by the parasite to evade macrophage-mediated immune destruction.     

Antibody-dependent murine macrophage-mediated damage to Schistosoma mansoni schistosomula in vitro

Antibody-dependent cell-mediated cytotoxicity (ADCC) against schistosomula of the human parasite Schistosoma mansoni was demonstrated using antisera from mice plus peritoneal exudate cells (PEC). PEC were divided into plastic-adherent (96% macrophages, 4% lymphocytes) and nonadherent (92% lymphocytes, 8% macrophages) cell populations. Four criteria of ADCC were used, including minimal and maximal cell attachment, and death of and uptake of trypan blue by schistosomula. Using cells from normal mice and antisera from schistosome-infected mice, macrophages adhered to, damaged the tegument and underlying structures of, and killed schistosomula when observed following 18 hr incubation. In homologous systems, the results were similar when outbred CD-1 and inbred BALB/c mice were compared, except that potency of antisera from the latter mice decreased after 6–7 weeks postinfection, whereas the opposite was true for the former strain of mice. Nonadherent cells also exhibited ADCC against schistosomula, but the potency was considerably lower than that of adherent cells. These complement-independent ADCC reactions were stage-specific for the schistosomulum in that no reactions occurred with adult worms.     

Survival of bird schistosomes in mammalian lungs

Bird schistosome cercariae have a low specificity to vertebrate skin and, thus, they are also able to penetrate into mammals. As a consequence, a hypersensitive skin response-cercarial dermatitis-develops. It was thought that the parasites die in the skin soon after penetration. Our results on Trichobilharzia szidati and Bilharziella polonica in the non-specific murine host confirm that some of the penetrating bird schistosomes may fully transform to schistosomula and migrate to the lungs. They persist there for up to 10days post exposure. In a duck, the worms grow and feed rapidly, but in a mouse the lung schistosomula seem to be inhibited in their development. However, TEM results show that there is no damage to the tegument of these larvae and no immune effector cells attack the parasites. These results suggest that the parasite's failure in the murine host might be caused by some immunologically unrelated factors.     

Schistosoma mansoni: topochemical features of cercariae, schistosomula, and adults

The teguments of developing and mature cercariae, recently transformed, and 1-wk-old schistosomula and adult worms were examined for the ultrastructural location of macromolecular carbohydrates and polyelectrolytes. The surface of mature cercariae within sporocysts and cercariae released from the snail is covered by a filamentous coat which reacts with cytochemical reagents for the demonstration of vicinal glycols, but neither the coat nor the surface of the tegument plasmalemma binds cationic colloidal iron at low pH.Upon penetrating mammalian skin, the cercaria sheds its surface coat; the tegument surface of newly transformed schistosomula, older schistosomula and adult worms stains en bloc with acidic colloidal iron, as does the tegument plasmalemma of mature cercariae if the overlying filamentous coat is first removed by physicochemical means. The cercarial coat thus serves to mask anionic groups at the surface of the tegument plasmalemma which become functionally exposed after penetration of the mammalian host. The distribution of colloidal iron binding sites coincides with those for the carbohydrate-complexing phytohemmagglutnin, concanavalin A, which suggests that these membrane-fixed anions are acid mucopolysaccharides, glycoproteins or glycolipids. Carbohydrate-containing material was also localized within membrane-bound vesicles of the tegument matrix and perikarya of developing cercariae and postcercarial schistosomes, suggesting that surface mucosubstances contributing to the tegument glycocalyx of these worms are elaborated, at least in part, by the tegument itself.     

<Emphasis Type="Italic">Trichobilharzia regenti</Emphasis>: Antigenic structures of intravertebrate stages

Like several other bird schistosomes, neurotropic schistosome of Trichobilharzia regenti can invade also mammals, including humans. Repeated infections cause cercarial dermatitis, a skin inflammatory reaction leading to parasite elimination in non-specific mammalian hosts. However, in experimentally primo-infected mice, the worms escape from the skin and migrate to the central nervous system. In order to evade host immune reactions, schistosomes undergo cercaria/schistosomulum transformation accompanied with changes of surface antigens. The present study is focused on localization of the main antigens of T. regenti; cercariae, schistosomula developed under different conditions and adults were compared. Antigens were localized by immunofluorescence and ultrastructural immunocytochemistry using sera of mice repeatedly infected with T. regenti. Detected antibody targets were located in glycocalyx and penetration glands of cercariae and in tegument of cercariae, schistosomula and adults. Shedding of cercarial glycocalyx significantly reduced surface reactivity; further decrease was reported during ongoing development of schistosomula. Spherical bodies, probably transported from subtegumental cell bodies to worm surface, were identified as the most reactive tegumental structures. Based on similar results for schistosomula developed in specific, non-specific hosts and in vitro, it seems that the ability of T. regenti to decrease the surface immunoreactivity during ontogenesis is independent on the host type.     

In vitro killing of S. mansoni schistosomula by eosinophils from infected rats: role of cytophilic antibodies.

The cytotoxic effect of peritoneal cells from Schistosoma mansoni-infected rats against antibody-opsonized or nonopsonized schistosomula in vitro has been studied during the course of infection. Eosinophil-enriched cell preparations were shown to have a high cytotoxic effect on schistosomula in the absence of antibody. The killer cells were identified as eosinophils. As in the ADCC mechanism previously described, mast cell-eosinophil interaction was required for eosinophil cytotoxicity. Rosette formation using S. mansoni antigen-coated erythrocytes was used to demonstrate the presence of anti-S. mansoni IgG2a antibody at the surface of infected eosinophils. Passive sensitization of normal eosinophils with ultracentrifugation pellets of immune rat serum resulted in a significant cytotoxicity of sensitized eosinophils. A close relationship was found between the cytotoxic activity of infected cells and the ability of the corresponding infected serum to arm normal eosinophils. At certain periods after infection, eosinophils from infected rats were less effective than normal eosinophils on antibody-coated schistosomula. EA- (rat) rosetting assay and blockade experiments with homologous immune complexes have revealed in a kinetic study that the blocking of cytotoxic activity of infected eosinophils was related to heat-stable circulating immune complexes. The possible role of immune complexes either in arming or inhibiting effector cells is suggested.     

Tegumental alterations in juvenile Schistosoma haematobium harboured in hamsters following artemether treatment

We report the findings of a detailed temporal study on tegumental alterations in juvenile Schistosoma haematobium, induced by artemether, using scanning electron microscopy. Hamsters infected with S. haematobium cercariae for 28 days were treated intragastrically with a single dose of 300 mg/kg artemether. Groups of two hamsters were killed 24 h, 72 h and 7 days after treatment, and schistosomula were recovered from livers by perfusion and subsequent systematic examination of the tissue, before routinely processing for scanning electron microscopic examination. Most schistosomula collected 24 h after artemether administration showed severe tegumental damage, usually including swelling, fusion, vesiculation, peeling and collapse of enlarged sensory structures. After 72 h, tegumental damage had increased and schistosomula generally showed contraction with extensive swelling, erosion and peeling of the tegument. Seven days post-treatment, severe tegumental damage was only seen in a single male specimen with swelling of the worm body and destruction of the oral sucker. The other schistosomula showed only light to moderate damage, suggesting that schistosomula surviving the treatment began to recover. Our findings of tegumental damage following artemether treatment correlate with the efficacy of this novel antischistosomal drug in killing the juvenile stages of S. haematobium and complement recent findings with S. japonicum and S. mansoni.     

Schistosoma mansoni: immunoblot analysis of adult worm proteins

Proteins of adult Schistosoma mansoni were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and assayed in immunoblots for reactions with individual mouse sera. Four weeks after a heavy infection with a few hundred cercariae, IgG antibodies directed predominantly against a protein of 31 kDa were detected. The protein was only weakly recognized by antibodies of mice harboring a 4-week-old light infection with about 60 cercariae. After 6 weeks or more, mice infected with either dose formed antibodies, not only against the 31-kDa protein and a 67-kDa protein, but also against a number of other components. While reactions with the 31- and 67-kDa proteins occurred with sera of all individual mice of four different strains, the reactions with other components were less consistently observed. Mice vaccinated with a heavy or light dose of 20,000-rad-irradiated cercariae did not form antibodies detectable in the blotting system. However, in immunofluorescence assays with living skin schistosomula, but not lung schistosomula, antibodies against the larval surface were detected with all sera obtained 4 weeks after infection or vaccination. In addition, immunofluorescence studies using the same sera and sectioned adult parasites demonstrated the presence of antibodies against the parasite surface in all sera except those obtained from mice exposed to a light infection with normal cercariae. Mice infected in this latter way were the only animals that did not develop a significant resistance against a challenge infection 4 weeks after exposure to normal or irradiated cercariae. The presence of an immunofluorescent reaction against the schistosome gut always coincided with a reaction of the sera with the 31-kDa protein in the immunoblots. Although a role in immune resistance could not be ascribed to any of the proteins reacting in the immunoblots, the data demonstrate important differences in the antibody specificities induced by various infection schemes.     

Three major surface antigens of Schistosoma mansoni are linked to the membrane by glycosylphosphatidylinositol

Schistosomula of Schistosoma mansoni were examined for the presence of glycosylphosphatidylinositol (GPI) anchored surface membrane Ag. Parasites were surface iodinated and cultured in the presence or absence of a crude phospholipase C (PLC) preparation or phosphatidylinositol-specific PLC (PIPLC). Culture supernatants were then analyzed: 1) by centrifugation to ascertain which molecules released from the surface were soluble or contained in membrane vesicles; 2) by immunoprecipitation with antibodies specific for the "cross-reacting determinant," an epitope revealed on some GPI-anchored proteins only after cleavage of the diacylglycerol from the protein by PIPLC, and 3) by immunoprecipitation with immune mouse sera to establish co-identity with previously described, immunologically relevant surface Ag. By using these techniques, schistosomula were shown to possess three GPI-anchored surface Ag of m.w. 38,000, 32,000 and 18,000 which are spontaneously released from the surface of schistosomula in association with membrane, but remain insoluble until cleaved by PIPLC. All three molecules were recognized by antibodies from mice vaccinated with irradiated cercariae and/or chronically infected mice. Moreover, the m.w. 38,000 component was recognized by a previously described protective mAb (E.1). A major developmental modification appears to occur in the expression of these molecules because, by the same techniques, no GPI-anchored surface Ag were detectable on 7-day-old lung stage parasites. The finding that these important parasite immunogens are GPI-anchored and released from the surface of the parasite in membrane vesicles may, in part, explain why they elicit strong immune responses capable of damaging the schistosomulum tegument.