弓形虫代谢分泌抗原疫苗对山羊流产高发区的免疫效果试验

制备以弓形虫E/SA（代谢分泌抗原）疫苗为主,辅以衣原体疫苗,对天祝县流产高发区的299只四群适龄母山羊（对照1群）在配种前进行免疫注射效果观测。结果在产羔期结束后统计流产率较往年显著降低,免疫后的三群羊分别由上年流产率的42%、36.7%、35%降为24.39%、0%和22.88%,流产率较上年度分别降低了41.92%、100%、34.62%,未免疫的对照群却上升了52.7%（37%上升为56.5%）。经现场考察和血清学分析,排除多种因素的干扰,证明弓形虫E/SA疫苗在本次免疫中效果显著。     

用弓形虫代谢分泌抗原制备间接血凝诊断试剂的研究

用弓形虫代谢分泌抗原(E／SA)致敏绵羊红细胞制备间接血凝诊断试剂，进行人和动物弓形虫病血清抗体检测，并用弓形虫虫体抗原致敏的红细胞间接血凝诊断试剂进行对照试验。结果表明，在弓形虫阴性、阳性血清检测中，弓形虫E／SA间接血凝诊断试剂与弓形虫虫体抗原间接血凝诊断试剂的符合率为100％；在人工感染兔血的检测中，E／SA致敏的间接血凝诊断试剂比虫体抗原致敏的间接血凝诊断试剂的阳性检出时间提前2d，显示弓形虫E／SA间接血凝诊断试剂具有早期诊断和生前诊断的应用价值。     

弓形虫病免疫的研究：弓形虫排泄分泌抗原制备及其对怀孕母羊免疫效…

弓形虫ＧＪＳ株速殖子通过传代细胞（ＢＨＫ－２１）培养，制备排泄分泌抗原（Ｅ／ＳＡ），蛋白含量为２．０９５ｍｇ／ｍｌ；ＳＤＳ－ＰＡＧＥ凝胶电泳分析显示２１条区带，分子量在１８～１２０ＫＤ，其中６８ＫＤ为主带，次带７条。用Ｅ／ＳＡ与佐剂（Ｍ－２０６）制备Ｅ／ＳＡ疫苗，对３０只（２公，２８母）弓形虫血检抗体阴性，混群自然交配５０天的适龄健康绵羊随机分组进行免疫，间隔２０天再加强免疫１次。第１组于混群后８     

细粒棘球绦虫排泄分泌抗原的研究——绵羊免疫后或感染后的抗体应答及细胞应答

绵羊用六钩蚴排泄分泌抗原(ES)，原头节ES抗原、原头节可溶性粗抗原，绵羊棘球蚴囊液(SHCF)或囊壁抗原免疫后，和攻击感染虫卵后，应用ELISA，酯酶染色法及瑞氏-姬拇萨染色法研究了血清抗体、T、B淋巴细胞、嗜酸性粗细胞及淋巴细胞的应答反应。初步结果表明，绵羊在感染细粒棘球绦虫虫卵后或抗原免疫后、攻击感染后都表现明显的血清抗体应答反应，T淋巴细胞、嗜酸性粒细胞及淋巴细胞数量增加，免疫应答依不同的抗原而具有不同性质。     

弓形虫免疫的研究：弓形虫E／SA的免疫原性和特异性淋巴细胞对小…

用弓形虫速殖子经细胞培养的排泄分泌抗原（Ｅ／ＳＡ）乳化后对小鼠免疫２次，７天后用强毒ＧＪＳ株速殖子以致死性剂量（１０＾３／只）腹腔注射攻毒效检，结果免疫鼠的存活时间明显长于对照鼠。在第二次试验中，Ｅ／ＳＡ免疫鼠通过眼眶放血致死，无菌条件下取其肠系膜淋巴结、腹股沟淋巴结、脾脏，制成单个细胞，在３７℃５％ＣＯ２条件下培养２天，以不同剂量注射小白鼠；并同时制备健康鼠淋巴细胞注射小白鼠。注射后第二天用ＧＪ     

感染IBDV雏鸡免疫器官对颗粒抗原的免疫应答

对１日龄感染和未感染传染性法氏囊病毒雏鸡接种小鼠红细胞后，免疫中枢器官（法氏囊、胸腺），外周免疫器官（脾脏），以及消化道和呼吸道相关的局部免疫组织（盲肠扁桃体、哈德尔腺）中浆细胞、ＡＮＡＥ＾＋Ｔ细胞、淋巴细胞数的变化及其分布进行了检测。结果表明：１日龄雏鸡感染传染性法氏囊病毒后，其免疫器官组织对小鼠体液免疫和细胞免疫应答均明显降低。     

抗弓形虫免疫

弓形虫又名弓浆虫,于1908年由Nicolle和Manceaux发现,是一种世界性分布的专性细胞内寄生原虫,可感染包括人类在内的所有哺乳动物。主要危害免疫损伤及免疫功能不健全的机体,家畜中引起妊娠母畜流产,仔畜弓形性脑炎,给畜牧业带来了严重的经济损失。因此,如何有效地诊断与防治弓形虫病愈来愈受到人们的关注与重视,尤其在弓形虫病免疫方面的研究更成为国内外学者研究的热点。     

保护性抗原和保护性免疫应答的特性

疫苗的保护性免疫应答，可能是由于循环抗体（体液）、激活的致性Ｔ淋巴细胞（细胞免疫）、粘膜表面的分泌型ＩｇＡ（粘膜免疫）的作用或是这些因素的联合作用，一般而言，体液免疫在抗本身性病素，细胞感染和抵抗毒素引起的疾病的保护中特别重要；细胞免疫在抗细胞内细菌、病毒感染，真菌病和原虫病的保护中特别重要，而分泌型ＩｇＡ的重要性则在于能抵抗病原吸附在上皮表面所引起的细菌病和病毒病以及抵抗毒素在粘膜表面引起的疾病     

新孢子虫与弓形虫交叉抗原AMA1基因重组腺病毒的构建及免疫应答分析

为构建新孢子虫和弓形虫AMA1基因重组腺病毒,并分析其免疫原性,本试验根据新孢子虫和弓形虫AMA1基因序列的开放阅读框,设计新孢子虫和弓形虫交叉抗原AMA1基因通用引物,构建重组克隆质粒pMD18T-NcAMA1、pMD18T-TgAMA1及重组腺病毒穿梭质粒ADV4-Nc/TgAMA1,将ADV4-Nc/TgAMA1和骨架质粒pacAd5线性化后共转染293T细胞,包装Ad5-Nc/TgAMA1重组腺病毒,测定病毒滴度后,收集病毒液接种BALB/c小鼠,间接ELISA检测小鼠血清IgG抗体水平。结果显示,Nc/TgAMA1在Ad5-Nc/TgAMA1重组腺病毒中获得表达,测定Ad5-Nc/TgAMA1重组腺病毒滴度为10⁹PFU/mL,接种BALB/c小鼠后,Ad5-Nc/TgAMA1接种组IgG抗体水平明显高于pVAX1-Nc/TgAMA1质粒组和PBS对照组。结果表明,构建的Ad5-Nc/TgAMA1重组腺病毒能诱导小鼠产生特异性体液免疫应答。本试验为新孢子虫和弓形虫交叉抗原AMA1基因重组腺病毒载体疫苗的研制奠定了基础。     

Immune responses against excreted/secreted antigens of Toxoplasma gondii tachyzoites in the murine model

In the present study, excretory secretory antigens (ESA) of Toxoplasma gondii were evaluated in immunization of 8-10 week inbred female Balb/c mice. Tachyzoites of the parasite were cultured in cell-free incubation medium (RPMI-1640), and then supernatant of the medium was loaded on an ion-exchange chromatography column. Two fractions (ESA-F(1) and ESA-F(2)) were collected from the column. For immunization of the mice, 50 were allocated into 5 groups of 10. The first, second, third, and fourth groups were immunized, twice with total-ESA, ESA-F(1), ESA-F(2) or toxoplasma lysate antigen (TLA), respectively. The fifth group was selected as a negative control group (non-immunized). The virulent RH strain of Toxoplasma gondii was used to challenge. Delayed-type hypersensitivity responses (DTHs) were measured by intra-footpad injection measuring induration at timed intervals. Lymphocyte transformation tests (LTTs) were done on lymph node cells using [3H] thymidine incorporation as an indication of reactivity. Peritoneal macrophages from sensitized mice were stimulated and nitric oxide was measured by Griess method. The ESA-F(1) and ESA-F(2) fractions were separated on poly acrylamide gel electrophoresis (PAGE) and SDS-PAGE. ESA-F(1) had 4 bands on PAGE and 14 bands on SDS-PAGE. ESA-F(2) had one band on PAGE and two bands on SDS-PGE. Sensitized mice showed DTH and lymphocyte transformation responses to total-ESA, ESA-F(1), and ESA-F(2) and peritoneal macrophages produce nitric oxide following stimulation. In challenge experiments, all non-immunized mice died within 10 days, whereas immunized mice survived for longer time periods (P<0.05). The highest survival rate was observed in mice that immunized with ESA-F(2). We suggest that these antigens especially ESA-F(2) should be of value for the development of new strategies for immunization against toxoplasmosis.     

Production of antibodies in murine mucosal immunization with Toxoplasma gondii excreted/secreted antigens

Toxoplasmagondii RH strain excreted/secreted antigens (ESA) were administrated weekly by the oral route, to two groups of 40 OF1 mice for 4 weeks. One group received ESA associated with cholera toxin (CT+) and the other, ESA only (CT-). Five animals from each group were sacrificed from day 4 (D4) to D49 following the first immunization and their feces and sera were collected and tested by ELISA for IgA, IgG and IgM antibody detection. In feces, IgA antibodies were detected on D4 and on D12 in the CT+ and CT- groups, respectively, and they persisted up to D49. IgG antibodies were detected from D12 to D41 in the CT+ group and on D12 only in the CT- group. No IgM antibodies were detected. In sera, IgA antibodies were detected on D27, D41 and D49 only in the CT+ group. IgG and IgM antibodies were found on D12 and D4, respectively, in the CT+ group and starting from D27 in the CT- group. To our knowledge, this is the first demonstration that ESA, with or without CT, are immunogenic when administrated by the oral route.     

Construction and Analysis of Immune Response of Neospora caninum and Toxoplasma gondii Cross Recombinant Adenovirus Antigen AMA1 Gene

In order to establish AMA1 recombinant adenovirus of Neospora caninum (N.caninum) and Toxoplasma gondii (T.gondii), and analyze the immunogenicity of it, cross universal primers were designed according to the open reading frame of N. caninum and T. gondii AMA1 gene sequences. Based on pMD18T-NcAMA1 and pMD18T-TgAMA1 cloning plasmid, recombinant adenovirus shuttle plasmid ADV4-Nc/TgAMA1 was constructed. Then, ADV4-Nc/TgAMA1 and pacAd5 backbone plasmid were linearized and co-transfected 293T cells. After packaging recombinant adenovirus and measuring the virus titer, collected virus was inoculated into BALB/c mice, confirmed the IgG antibody levels by indirect ELISA method. The results showed that Nc/TgAMA1 was expressed in Ad5-Nc/TgAMA1 recombinant adenovirus, Ad5-Nc/TgAMA1 recombinant adenovirus titer was 10⁹ PFU/mL. IgG antibody levels in the Ad5-Nc/TgAMA1 vaccinated group were significantly higher than pVAX1-Nc/TgAMA1 plasmid group and PBS control group. This result indicated that the constructed Ad5-Nc/TgAMA1 recombinant adenovirus could induce specific humoral immune response in mice, this research laid a solid foundation for the development of a recombinant adenovirus vaccine against N. caninum and T. gondii.     

细胞渗透肽TAT与3种弓形虫抗原的融合重组表达

为了探索新型弓形虫疫苗的传递系统,本试验分别构建了细胞渗透肽反式转录激活因子(TAT)与3种弓形虫抗原和增强型绿色荧光蛋白(EGFP)融合表达的重组质粒,即pET28a-TAT-EGFP,pET28a-TAT-SAG1,pET28a-TAT-GRA4和pET28a-TAT-AMA1质粒。重组质粒被转化到大肠杆菌中并通过IPTG诱导,成功进行了融合表达,表达产物采用Ni-NTA树脂进行纯化,然后进行SDS-PAGE分析。结果得到31 ku的TAT-EGFP融合蛋白、34 ku的TAT-SAG1融合蛋白、38 ku的TAT-GRA4融合蛋白和62 ku的TAT-AMA1融合蛋白,经过Western blotting分析,感染弓形虫的小鼠血清可特异性地识别融合TAT的SAG1、GRA4蛋白和微弱地识别TAT-AMA1蛋白。     

弓形虫胚层发育相关蛋白的原核表达及免疫原性研究

试验旨在研究弓形虫胚层发育相关蛋白（TgERP）的免疫原性,以弓形虫RH株的基因组DNA为模板,扩增TgERP基因,将其连接于表达载体pET-30a(+)后,转化至Escherichia coli BL21（DE3）感受态细胞进行IPTG诱导表达,应用Western blotting对重组蛋白的反应原性进行分析,并用纯化后的TgERP蛋白免疫新西兰大白兔,制备多克隆抗体。结果显示,在37 ℃条件下用1.0 mmol/L IPTG诱导6 h表达可溶性TgERP蛋白的量最大。SDS-PAGE结果显示,目的蛋白分子质量为16.7 ku,以可溶形式表达,纯化后蛋白条带单一。经Western blotting分析,TgERP蛋白有较好的反应原性;制备的多克隆抗体效价较高,可达1∶51200,表明该蛋白具有较好免疫原性。提示,TgERP蛋白可作为血清学诊断方法的候选抗原和弓形虫病疫苗的候选分子,为建立弓形虫新型诊断方法和研制新型弓形虫疫苗奠定了基础。     

屠宰羊弓形虫感染情况调查

为了保障羊肉制品的生物安全,对屠宰羊进行弓形虫感染情况调查以及对羊肉进行弓形虫检测。采用间接血凝试验,对677份屠宰羊的血清进行了弓形虫抗体检测。结果显示,弓形虫抗体阳性有47份,阳性率为6.9%。     

Keratoconjunctivitis associated with Toxoplasma gondii in a dog

A 12-year-old Pug presented with a 3-mm corneal mass OD. The dog was currently being treated for keratoconjunctivitis sicca (KCS) and pigmentary keratitis OU. A superficial keratectomy followed by cryotherapy was performed OD. A histopathologic diagnosis of epithelial dysplasia and suppurative keratitis was made and the lesion resolved. Two months later, a yellow/tan conjunctival mass, diffuse chemosis and conjunctival thickening was discovered OD. Necrotizing conjunctivitis with protozoal parasites was diagnosed with histopathology. Complete blood count and a serum biochemistry panel were normal. Neospora caninum and Toxoplasma gondii titers were negative. The conjunctivitis resolved after a 6-week course of oral clindamycin. Two months later, the patient presented with a similar conjunctival mass OS. Toxoplasma gondii was confirmed as the etiologic agent with immunohistochemical staining. Repeat T. gondii titers were negative. Oral clindamycin was re-instituted. The corneal biopsy was re-reviewed and protozoal organisms were discovered. Three months later, a recurrence was suspected and oral ponazuril was initiated for 28 days. There has been no evidence of recurrence since this treatment. Ocular toxoplasmosis is rare in the dog but reports have included episcleritis, scleritis, retinitis, anterior uveitis, ciliary epithelium hyperplasia, optic neuritis and polymyositis. To our knowledge, this is the first confirmed report of toxoplasmosis causing only corneal and conjunctival disease in the dog. We hypothesize that these localized lesions may be associated with topical immunomodulating therapy for KCS. Toxoplasmosis should be considered as a differential for canine conjunctivitis and corneal disease and has the potential to manifest in one or both eyes.     

A Brief History and Overview of Toxoplasma gondii

Toxoplasma gondii was discovered by scientists working in North Africa and Brazil around 100 years ago. The parasite has since been found to be capable of infecting all warm‐blooded animals including humans making it one of the most successful parasitic organisms worldwide. The pathogenic potential of T. gondii was recognized in the 1920s and 1930s, in congenitally infected children presenting with the classic triad of symptoms, namely hydrocephalus, retinochoroiditis and encephalitis. In addition, around the same time T. gondii parasites were found to be associated with severe intraocular inflammation. In the 1980s, T. gondii emerged as a major cause of death in patients with acquired immunodeficiency syndrome, illustrating the importance of the immune system in controlling T. gondii infection. T. gondii was reported as a major cause of abortion in sheep in New Zealand in the 1950s, which raised questions about potential new transmission routes for the parasite. The discovery of the cat as the definitive host in the 1960s was a very important finding as it helped to complete our understanding of the parasite’s life cycle, and the oocyst stage of T. gondii shed in the faeces of infected cats was found to be an important source of infection for many intermediate hosts and helped to explain infection in herbivorous animals and people with a vegetarian diet. In addition, this stage of the parasite was very robust and could survive in the environment, depending on the climatic conditions, for up to 12–18 months. Knowledge of the parasite’s lifecycle, transmission routes, risk groups and host immune responses has helped in the development of strategies to control the disease, reduce transmission of the parasite and limit environmental contamination.