紫外线减毒弓形虫对小鼠旋毛虫感染的影响

目的探讨紫外线减毒弓形虫免疫对小鼠旋毛虫感染的影响。方法ICR小鼠分为两组，实验组为紫外线减毒弓形虫免疫3周后再感染旋毛虫，对照组为旋毛虫单独感染。结果与旋毛虫单感染相比，小鼠预先经紫外线减毒弓形虫免疫再感染旋毛虫，在感染后5～14d其小肠内的成虫数明显增加（肠道排虫明显延迟），而感染后23-90d其肌肉中的幼虫数明显下降。结论紫外线减毒弓形虫免疫对小鼠旋毛虫感染具有一定的免疫调节和异源性保护作用。     

THE EFFECT OF INTRACEREBRAL IMMUNIZATION OF C57BL/6 MICE FOLLOWING CHALLENGE WITH T.GONDII ON IFN-γ AND TNF-α PRODUCTION IN BRAIN

脑传统上被认为是一个免疫学上特殊的器官。我们观察到用丝裂霉素处理过的弓形虫脑内免疫小鼠，可防止弓形虫感染后引起的小鼠的死亡，未接受免疫的小鼠，弓形虫感染后，敏感性小鼠与抵抗性小鼠相比，敏感性小鼠脑内有高水平的ＩＦＮ－γ、ＴＮＦ－α及ＩＬ－６。本研究观察了脑内免疫的小鼠，经几种不同途径的弓形虫负荷后，脑内及脾脏内淋巴介素的变化情况。与腹腔内或肠道内免疫途径相比，脑内免疫可引起弓形虫负荷后，脑内ＩＦＮ－γ和ＴＮＦ－α水平明显升高；而在脾脏，弓形虫负荷后ＩＦＮ－γ和ＴＮＦ－α产生，经肠道免疫的比经腹腔内和脑内免疫的要显著的高。这种淋巴介素产生的不同可能产生于不同的免疫途径诱导不同的Ｔｈ淋巴介素类型。以上结果也提示了脑本身具有内在性的抵抗微生物感染的免疫功能。     

弓形虫MIC8基因对弓形虫病的免疫保护性研究

目的观察弓形虫MIC8基因对弓形虫病免疫保护性的效果。方法用PCR方法扩增弓形虫MIC8基因,定向克隆到真核表达质粒pEGFP-N1中,构建重组表达载体pEGFP-MIC8;MIC8-EGFP转染293T细胞,荧光显微镜观察表达情况;然后分别用质粒pEGFP-MIC8、pEGFP-N1空载体及生理盐水肌肉注射免疫BALB/c小鼠,共免疫3次,末次免疫3周后用弓形虫RH株速殖子感染免疫小鼠。结果 PCR扩增弓形虫MIC基因序列正确,构建的重组表达载体pEGFP-MIC8鉴定正确,荧光显微镜下观察到重组质粒能够在293T细胞中表达。弓形虫攻击感染后,质粒pEGFP-MIC8免疫小鼠与对照组相比,小鼠的存活时间有一定的延长。结论构建的真核表达重组质粒pEGFP-MIC8对抗击弓形虫攻击感染能够激发一定的免疫保护性。     

吞噬细胞活性氧在抗弓形虫中的作用

弓形虫是一种专性细胞内寄生原虫，也是最常见的机会性感染病原体之一。研究发现，吞噬细胞在宿主抗弓形虫感染的免疫方面起重要作用，其杀虫机制是通过释放活性氧对弓形虫细胞膜及大分子物质造成氧化损伤。本文介绍小鼠、大鼠及人类吞噬细胞杀灭弓形虫或抑制其增殖的机理。     

紫外线减毒弓形虫免疫对小鼠旋毛虫感染肌肉组织病理的影响

目的探讨紫外线减毒弓形虫免疫对小鼠旋毛虫感染肌肉期组织病理的影响。方法ICR小鼠分为两组，实验组为紫外线减毒弓形虫免疫3周后再感染旋毛虫，对照组为旋毛虫单独感染。结果与旋毛虫单感染相比，小鼠预先经紫外线减毒弓形虫免疫再感染旋毛虫后23d，其肌肉期幼虫周围的炎症细胞浸润明显减轻，肌肉组织的病理损伤也明显减轻。结论紫外线减毒弓形虫免疫对小鼠旋毛虫感染肌肉期的组织病理有一定的免疫调节作用。     

改良Hale胶体铁组合染色用于杯状细胞染色效果

肠道是人体内极为重要的器官,不仅具有消化吸收营养物质和产生多种激素的作用,还具有重要的免疫屏障功能.肠道黏膜表面覆盖着一层保护性黏液凝胶,该凝胶及其周边的多种细胞通过病理生理机制共同参与维持肠道稳态.杯状细胞是肠道黏膜免疫屏障功能中产生免疫应答反应的重要细胞,其分化和分泌功能的改变可导致黏液凝胶成分的改变,在肠道疾病的...     

PI-IBS小鼠肠黏膜γδT细胞表型和功能变化的实验研究

目的:探讨PI-IBS小鼠γδT细胞的表型和功能及其在PI-IBS发病中的作用。方法:旋毛虫感染小鼠,观察肠道炎症、腹壁撤退反射(内脏高敏感性)和结肠传输时间(肠道动力)。分别在感染后第2周和第8周处死动物,取末端回肠和近端结肠组织,免疫荧光组化,激光扫描共聚焦显微镜观察肠黏膜γδT细胞的分布和数量变化。收集PI-IBS小鼠肠道淋巴结和脾脏的淋巴细胞,单克隆抗体免疫磁珠分选法分离和纯化γδT细胞,3HTdR法检测其增殖情况,FACS检测其表面分子CD69、CD62L,ELISA检测细胞培养上清液中IFN-γ及IL-17的表达。结果:感染后第2周,PI-IBS小鼠肠道炎症明显,肠黏膜γδT细胞数量明显增加,明显增殖和活化,产生IL-17明显增加(P0.01)。感染后第8周,PI-IBS小鼠肠道炎症基本消退,动物的腹壁撤退反射和结肠传输试验明显异常。肠黏膜γδT细胞数量仍然明显高于对照组小鼠,仍然有明显增殖、活化和产生IL-17(P0.01)。结论:肠道γδT细胞增殖、活化及分泌IL-17可能参与PI-IBS的发病。     

弓形虫感染宫内垂直传播的免疫特点

弓形虫感染宫内垂直传播对母体胎儿有很大危害。妊娠母体处于特殊的免疫状态，即正常妊娠是以Th2型免疫为主，以避免细胞免疫对胎儿的危害；而感染弓形虫后的机体是以Th1型免疫为主来防御细胞内寄生原虫的危害；这两种免疫反应之间的矛盾造成感染弓形虫的母体免疫反应的进一步偏移。这种矛盾的免疫现象也与性激素的免疫抑制作用和子宫内局部免疫有关。同时，由于体液免疫各抗体在母体和胎儿的弓形虫感染宫内垂直传播中变化复杂，给疾病诊治带来很大困难。     

弓形虫多表位DNA疫苗的构建及其免疫保护作用

目的:构建弓形虫多表位DNA疫苗并研究其免疫保护效果.方法:将编码含弓形虫多个T、B细胞表位的6段弓形虫多肽基因,以5个甘氨酸编码基因相间隔相连接,克隆入真核表达质粒pcDNA3.1( )中,构建成多表位弓形虫DNA疫苗.免疫BALB/c小鼠,测定其诱导的特异性抗体水平及T淋巴细胞增殖状况,同时进行弓形虫攻击感染保护实验.结果:成功构建了包含多个弓形虫表位的真核表达质粒pcDNA3.1/T-ME,以其作为DNA疫苗免疫小鼠,可诱导机体产生弓形虫特异性的体液及细胞免疫应答,产生有效的抗弓形虫保护性免疫应答.结论:构建的弓形虫多表位DNA疫苗能诱导机体产生有效的保护性免疫应答,在控制弓形虫感染上具有可行性.     

肠道菌群定植与B淋巴细胞免疫的研究概况

肠道菌群不仅在机体代谢方面起重要作用,而且参与了免疫系统的发育及功能调控。肠道菌群与肠道免疫系统的"平衡"在机体免疫应答、免疫耐受过程中起重要作用。其中,B淋巴细胞(简称B细胞)是体液免疫中产生抗体的重要细胞,还参与抗原提呈,在免疫系统中发挥重要作用。国内关于肠道菌群定植与B细胞免疫的关系研究较少,本文主要就肠道菌群定植与机体肠道免疫系统、免疫组织、B细胞及黏膜免疫调节之间的关系进行综述。     

Mucosal and systemic cellular immune responses induced by Toxoplasma gondii antigens in cyst orally infected mice.

This study was performed to determine the T-cellular immune responses following Toxoplasma gondii oral infection and to assess further toxoplasma antigens on their ability to stimulate in vitro mucosal and systemic T-cell immunity. Parasite-specific cellular immune responses in Peyer's patches (PP), in mesenteric lymph nodes (MLN) and in spleen (SPL) were investigated using a lymphoblastic transformation test following oral infection of mice with strain 76K cysts of T. gondii. An early toxoplasma sonicate-induced mucosal T-cell proliferation occurred in MLN and PP with a peak responsiveness on day 6 post-infection (PI) and rapidly reached background levels on day 7 PI in PP and on day 8 PI in mesenteric lymph nodes. A later splenic cellular blastogenesis was observed from day 28 PI and persisted throughout the experiment (day 91). At the time of T-cell proliferation, FACS analyses revealed a decrease in the relative percentages of CD4+ and CD8+ T cells with a predominance of CD8+ lymphocytes which leads to an inversion of the CD4/CD8 ratios. We found that CBA/J is a high responder mouse strain in the induction of mesenteric and splenic T-lymphocyte blastogenesis compared to the intermediate responder BALB/c and low responder C57BL/6. Toxoplasma gondii antigens SAG1 (30,000 MW) and GRA4 (40,000-41,000 MW), which are known to induce locally IgA antibodies, are shown to stimulate primed mucosal T lymphocytes from CBA/J and BALB/c mice whereas no proliferation was demonstrated with C57BL/6 T cells. 229-242 peptide, derived from the deduced amino acid sequence of GRA4, only induces detectable proliferation of primed-CBA/J T lymphocytes. Following oral experimental infection, the in vitro mesenteric response to a toxoplasma sonicate is dominated by a Th2-type cytokine pattern whereas a predominant Th1 cytokine response is observed in the spleen. Finally, in vitro stimulation of mesenteric T cells with the three defined toxoplasma antigens resulted in secretion of interleukin-5 (IL-5) and IL-6 (except for SAG1) and interferon-gamma (IFN-gamma) whereas no detectable IL-2 or IL-4 was observed.     

Toxoplasma infection and systemic lupus erythematosus: analysis of the serological response by immunoblotting.

AIMS--To examine the serological response of patients with systemic lupus erythematosus (SLE) and toxoplasma infection and to compare the blot profiles with those from immunocompetent subjects of similar immune response. METHODS--Forty serum samples from patients with SLE were tested for toxoplasma antibodies using the dye and indirect haemagglutination tests. Specific IgM was measured by mu-capture enzyme linked immunosorbent assay (ELISA). The sera were immunoblotted using antigen strips prepared from the RH strain of Toxoplasma gondii. For comparison, control blots were prepared from pooled sera from immunocompetent subjects with serological evidence of acute (pool 1), or chronic (pool 2) toxoplasma infection, or with no evidence of infection (pool 3). RESULTS--Some of the blot profiles from the patients with SLE were compatible with the corresponding serology but others showed considerable variation, particularly among the IgM blots. The blots from sera with low dye test titres suggested that the latter could be false positive results. CONCLUSIONS--Toxoplasma infection may enhance the production of autoantibodies which, when combined with the high titres characteristic of SLE, might interfere in the dye test and other serological tests. Immunoblotting could prove useful in the immunocompromised for confirming the presence of specific toxoplasma antibodies and for the staging of infection in those with positive serology.     

Pinocytic rates of macrophages from mice immunized against Toxoplasma gondii and macrophages stimulated to inhibit toxoplasma in vitro.

The rate of pinocytosis by macrophages when measured by uptake of horseradish peroxidase was significantly reduced during toxoplasma infection of the cells in vitro when the macrophages were from toxoplasma-immune mice and when control cells were stimulated in vitro to inhibit toxoplasma multiplication. There was, however, no direct correlation between reduced pinocytosis in this model and inhibition or enhancement of toxoplasma multiplication. We conclude that a reduced pinocytic rate is a feature of the unstimulated toxoplasma-immune macrophage, but this change in rate alone does not correlate with the cell's ability to inhibit toxoplasma. In addition, we observed that enhanced pinocytosis as seen in the elicited macrophage was not a requirement for inhibition of toxoplasma multiplication.     

Relevance of the toxoplasma IgG avidity test in the serological surveillance of pregnant women

In addition to the serological systematic screening tests, kits to measure the avidity of toxoplasma IgG antibodies are currently available. Since high-avidity IgG toxoplasma antibodies have been shown to exclude recent infection, IgG avidity determination is especially useful in ruling out acute infection having occurred in the 3-4 prior months of pregnancy. We therefore compared the efficacy of two toxoplasma IgG avidity ELISA kits: SFRI (SFRI Laboratoire) and VIDAS Toxo-IgG avidity kit (bioMérieux). The agreement of the results from the 2 commercial assays were analysed using 55 serum samples, in terms of global mother-child Toxoplasma results and outcome, specially with light of the results of Toxoplasma antenatal, postnatal assays and of clinical follow up of children.     

A new agglutination reaction for the diagnosis of the developmental stage of acquired toxoplasmosis

Agglutination of acetone treated toxoplasma (AC) is different from that one of formalin fixed parasites (HS). Sera from patients with a recently acquired ("acute") infection agglutinate both HS and AC parasites suspensions as well; contrary to sera from patients with past infection ("chronic stage") in which high titers of HS agglutination are often present, while the titres of AC agglutination are lower even negative. This is markedly observed in patients with local lesions (relapsing chorioretinitis, patients with AIDS and brain abscesses). The reason might be that different membrane toxoplasma antigens may induce the synthesis of agglutinating IgG. For example, antigens 35 KD and 27 KD described by E. Handman et al. The antibody specific for 27 KD is apparently present mainly during acute infection, contrary to the antibody specific for 35 KD which might be responsible of the high HS agglutination titre in sera from patients with chronic infection. Even if these hypotheses were not confirmed in the future, comparison of the titre in the HS and AC agglutination test might actually be helpful for practical diagnosis of the stage of toxoplasma infection.     

Serological screening for antenatal toxoplasma infection in India

Purpose: Detection of infection caused by Toxoplasma gondii during pregnancy to prevent congenital infection. Materials and Methods: This study was carried out from January 2005 to 2006 in 300 pregnant women. Antitoxoplasma IgG, IgM, IgA antibody and IgG avidity were assessed using ELISA. Atleast two samples were taken atleast 3 weeks apart preferably one in each trimester. Result: Of these 300 pregnant women, anti toxoplasma IgG antibodies were detected in 46 (15.33%) cases, while 9 (3%) had positive anti toxoplasma IgM with IgA and /low IgG avidity antibodies suggestive of acute infection during or just before pregnancy. Conclusion: The results indicate that about 85% of female population of Chandigarh is susceptible to toxoplasma infection and thus should be specifically educated about prevention of this infection during pregnancy     

Localized lymphadenitis due to leishmania simulating toxoplasmosis. Value of electron microscopy for differentiation

Two cases of cervical adenopathy are described. One manifested as lymphoma clinically. Both patients were found to have primary lymph node leishmaniasis without cutaneous, mucosal or visceral involvement. The histologic appearance simulated toxoplasma lymphadenitis. Electron microscopic study differentiated the organism from Toxoplasma, and the condition responded well to antimony therapy.     

Immunohistological study of the anatomic relationship of toxoplasma antigens to the inflammatory response in the brains of mice chronically infected with Toxoplasma gondii.

The relationship of toxoplasma antigen(s) to the origin and long-term persistence of the mononuclear cell inflammatory infiltrate that is present in the brains of mice chronically infected with Toxoplasma gondii was studied by using the peroxidase-antiperoxidase immunohistochemical staining technique. C3H/Km mice were infected with the avirulent C37 strain of T. gondii and sequentially sacrificed over the ensuing 107 days. Comparable sections of each brain were prepared for routine light microscopy. Antisera to toxoplasma made in rabbits were used for immunohistological staining, and adjacent slides were also stained with conventional histological stains. The peroxidase-antiperoxidase stain demonstrated toxoplasma tissue cysts, tachyzoites, and intra- and extracellular antigen-antibody reaction products. Early infection was characterized by small tight clusters of free tachyzoites gaining access to brain substance in the absence of an inflammatory response. Once there was disruption of neural parenchyma, a mononuclear cellular infiltrate rapidly ensued. After the first days of infection, mononuclear cells were always present in all infected brains and were anatomically associated with some component of toxoplasma antigen(s). The histological picture of late infection suggested that recurrent episodes of hematogenous dissemination of tachyzoites occurred in infected mice and that such episodes were at least partially responsible for persistence of an antigenic stimulus.     

巨细胞病毒、风疹病毒、弓形虫在已婚育龄妇女中的检测结果分析及调查

目的了解已婚育龄妇女巨细胞病毒、风疹、弓形虫感染情况.方法于2001年5月至2003年10月由我站对全县已婚育龄妇女进行查体,同时抽取血液,采用ELISA方法对巨细胞病毒、风疹病毒、弓型虫抗体进行测定.同时对筛查对象作有关情况调查.结果本县已婚妇女巨细胞病毒感染率6.4%、风疹病毒感染率2.7%.弓形虫感染率6.1%.与正常妊娠组比较,已婚未育组感染率有显著性差异(P＜0.05),异常妊娠组有极显著性差异(P＜0.01),且有动物接触史及有生食习惯者感染率明显高于无动物接触史及无生食习惯者(P＜0.05).结论巨细胞病毒、风疹、弓形虫感染是引起不良生育的主要原因之一,建议已婚育龄妇女孕前加强筛查工作,早诊断、早治疗,确保生1个健康聪明的下一代.     

Discrepant toxoplasma latex agglutination test results.

The analysis of 4450 toxoplasma serology results showed that 59 (1.3%) latex agglutination reactions were not confirmed in the dye test. These discrepant results were associated with an unspecified IgM antibody but not associated with kit batch variation, inactivation of sera, concurrent cytomegalovirus infection, or the presence of hepatitis B virus "e" antigen. The latex agglutination test is useful as a screen for toxoplasma infection but false positive reactions do occur. Patients at risk of severe toxoplasmosis should be investigated by additional tests.