阿奇霉素对沙眼衣原体感染后生殖道黏膜免疫反应的影响

目的 研究阿奇霉素治疗生殖道沙眼衣原体感染过程中对局部黏膜免疫反应的影响,为其临床应用提供新的实验依据.方法 构建小鼠生殖道沙眼衣原体感染模型,随机分为生理盐水组和阿奇霉素组.阿奇霉素组一次性给予阿奇霉素（80mg/kg）,生理盐水组给予等量生理盐水.给药当天、给药第7天、给药第14天和给药第21天,阴道拭子取宫颈脱落细胞,分离沙眼衣原体.给药21天,处死动物.收集血清,ELISA测定血清IL-6和TNF-α水平,同时进行阴道、宫颈黏膜常规HE染色和肥大细胞甲苯胺蓝染色、树突状细胞免疫组织化学分析.结果 1.阿奇霉素组沙眼衣原体感染率明显低于生理盐水组,且未出现上行感染（P〈0.05）.2.阿奇霉素组生殖道黏膜内树突状细胞数量增加（P〈0.05）,肥大细胞数量无明显变化（P〈0.05）.3.阿奇霉素组血清内IL-6和TNF-α的水平,均高于对照组和生理盐水组（P〈0.05）.结论 阿奇霉素除了有效清除生殖道沙眼衣原体感染,亦可以调节生殖道黏膜的免疫反应,减轻免疫病理损伤,使沙眼衣原体感染有较好的预后.     

沙眼衣原体分泌性蛋白Pgp3滴鼻免疫增强小鼠对衣原体生殖道感染的保护作用

【目的】探讨不同免疫途径沙眼衣原体(Chlamydia trachomatis,Ct)分泌性蛋白Pgp3的免疫保护效果,分析其可能的保护机制,以确定Pgp3蛋白疫苗在Ct疫苗研制中的应用价值。【方法】分泌性蛋白Pgp3经滴鼻或肌注途径免疫雌性Balb/c小鼠,免疫60 d后,阴道接种鼠沙眼衣原体(Chlamydia muridarum,Cm)建立生殖道感染动物模型,在该模型中评价Pgp3蛋白疫苗抗Cm感染的保护效果,并探讨其机制。【结果】滴鼻或肌注免疫后,小鼠血清及生殖道中检测到了特异性抗体;小鼠脾淋巴细胞产生IFN-γ、IL-17及IL-5水平均明显高于对照组,且滴鼻免疫组IFN-γ水平升高较肌注组更显著(P<0.05);Pgp3蛋白滴鼻免疫组小鼠经Cm生殖道感染后,阴道带菌时间明显缩短,输卵管病理改变轻而肌注免疫组其保护作用不明显。【结论】Pgp3蛋白经滴鼻免疫可有效诱导小鼠产生明显的抗Cm保护效应。其可能的免疫保护机制与诱导Th1型为主的细胞免疫应答及高效价的特异性抗体有关,提示Pgp3蛋白疫苗具有潜在的疫苗研究与开发价值。     

沙眼衣原体生殖道感染的小鼠模型及其应用

沙眼衣原体生殖道感染是严重危害人类生殖健康的一种常见的性传播疾病,研制安全、有效的疫苗是控制其感染的有效措施。在疫苗的研制中选择合适的动物模型非常重要。近几十年来学者们建立了多种沙眼衣原体生殖道感染的小鼠模型,根据接种途径可分为阴道内接种和子宫或卵巢囊内接种两大类。研究发现不同模型各有利弊,本文对两大类沙眼衣原体生殖道感染小鼠模型及其应用进行了综述。     

靶向M细胞的抗原递送¾¾增强黏膜免疫应答的关键策略

黏膜是阻止病原入侵的第一道防线,黏膜免疫系统在抵抗感染方面起着至关重要的作用。通过黏膜途径接种疫苗可以同时诱导黏膜和全身免疫反应,因此,理论上针对黏膜的免疫策略是最合理和有效的。但黏膜免疫系统的复杂性和屏障作用造成抗原诱导的免疫应答水平低下,制约了黏膜疫苗的发展。M细胞(Microfoldcells)是黏膜免疫系统所独有的,其具有捕获腔内抗原和启动抗原特异性免疫应答的功能。M细胞摄取抗原的多少直接关系到黏膜疫苗的免疫效力,而利用M细胞配体可将抗原靶向递呈给M细胞,从而实现高效的黏膜免疫应答。靶向M细胞的抗原递送策略及其应用可以提高黏膜免疫应答水平,促进黏膜疫苗的研制。尽管如此,要成功研制安全高效的黏膜疫苗,今后依然有漫长的路要走,这可能有赖于进一步探究M细胞的特性和功能及黏膜免疫机制。     

T细胞免疫在抗结核杆菌感染中的研究进展

结核分枝杆菌是引起结核病的病原体,该细菌可侵犯全身各组织器官。结核病是一种慢性传染性疾病,具有持久性特点。该细菌为胞内寄生菌,特异性免疫以细胞免疫为主,主要包括CD4+T细胞免疫和CD8+T细胞免疫。结核分枝杆菌特异性免疫应答的特点之一是感染早期T细胞免疫应答延迟。其机制与结核杆菌抑制免疫细胞(CD4+和CD8+T细胞及DC)凋亡延迟应答,通过特异性Treg细胞抑制作用延迟应答以及结核杆菌慢性感染期间存在IFN-γ信号调节网络和ESAT-6抗原的慢性刺激作用有关,以此可调节和维持免疫应答。深入了解抗原特异性T细胞特异性免疫应答的机制,有益于抗结核疫苗的研制,为临床工作提供理论依据和科学方法。     

T细胞免疫在抗结核杆菌感染中的研究进展

结核分枝杆菌是引起结核病的病原体,该细菌可侵犯全身各组织器官。结核病是一种慢性传染性疾病,具有持久性特点。该细菌为胞内寄生菌,特异性免疫以细胞免疫为主,主要包括CD4＋T细胞免疫和CD8＋T细胞免疫。结核分枝杆菌特异性免疫应答的特点之一是感染早期T细胞免疫应答延迟。其机制与结核杆菌抑制免疫细胞（CD4＋和CD8＋T细胞及DC）凋亡延迟应答,通过特异性Treg细胞抑制作用延迟应答以及结核杆菌慢性感染期间存在IFN-γ信号调节网络和ESAT-6抗原的慢性刺激作用有关,以此可调节和维持免疫应答。深入了解抗原特异性T细胞特异性免疫应答的机制,有益于抗结核疫苗的研制,为临床工作提供理论依据和科学方法。     

初免-加强免疫策略在疫苗研究中的应用

大多数传统疫苗的免疫保护机理主要是诱导能维持较长时间的体液免疫应答,而大量研究显示机体在对抗胞内感染微生物及一些病毒的感染时,细胞免疫应答是至关重要的。鉴于初始-加强(Prim e-Boost)免疫策略在诱导细胞免疫应答方面具备的优势,其显示了很好的应用前景,本文综述了Prim e-Boost免疫策略在疫苗研究中的应用并对其机制进行了初步的探讨。     

沙眼衣原体疫苗候选抗原研究进展

沙眼衣原体(CT)是引起感染性致盲的首要病因,也是引起性传播疾病的主要病原体。CT感染缺乏明显的临床症状,临床上容易被忽视而引起严重的疾病,故疫苗是预防CT生殖道感染经济有效的措施之一。综述了CT疫苗候选抗原的结构特点,免疫保护作用及其在预防CT感染性疾病的应用前景。     

结核杆菌感染T细胞介导免疫应答研究的新进展

结核病对免疫学家构成了巨大的挑战,因为它是一种慢性传染性疾病,病原体具有持久性特点.在对人和动物进行实验时,检测到结核分枝杆菌适应性免疫应答的特点之一为感染早期T细胞免疫应答延迟.新近研究揭示了此种延迟应答的机制:通过结核杆菌抑制免疫细胞(CD4+和CD8+T细胞及DC)凋亡延迟应答,通过特异性Treg细胞抑制作用延迟应答.结核杆菌慢性感染期间存在IFNγ信号调节网络和ESAT-6抗原的慢性刺激作用,抗原特异性PD-1+ CD4+T细胞具有高度增殖分化为更多终末效应性T细胞的潜能,以此可调节和维持免疫应答.深入了解抗原特异性T细胞调节与维持适应性免疫应答的机制,有益于抗结核疫苗的设计和研制.     

人类免疫缺陷病毒黏膜疫苗

在以往的20年间,有关发展艾滋病疫苗的研究曾经进行了大量的工作,但进展不大,通常诱生基于抗包膜抗体的疫苗效果并不理想。目前一般认为,细胞免疫应答,特别是CD8细胞毒性T淋巴细胞(CTL)／抑制细胞和CD4辅助性T淋巴细胞在人类免疫缺陷病毒的控制上是必需的。因此能诱生细胞免疫应答的疫苗在控制人类免疫缺陷病毒的播散上至关重要。本文阐述了有关黏膜疫苗的理论、艾滋病黏膜疫苗的种类以及经口免疫耐受性问题,并提出艾滋病应当视为一种自身免疫病。故抗炎症或免疫抑制药物应用似有其可取之处。     

Primary and secondary immune responses of mucosal and peripheral lymphocytes during Chlamydia trachomatis infection

Chlamydia trachomatis infection is followed by the development of antigen-specific cell-mediated immunity, which is detectable as a positive lymphocyte proliferation response to the chlamydial major outer membrane protein (MOMP) antigen. To date, however, there have been no studies on the mucosal immune responses to chlamydial antigens. This study aimed to study the primary and secondary immune responses of cervical lymphocytes in response to the chlamydial antigen. Median proliferative responses were found to be significantly (P<0.05) higher in patients with chlamydial infections than in controls. The chlamydial MOMP induced significantly higher IL-6 and IL-10 and lower interferon-gamma (IFN-gamma) secretion in cervical lymphocytes of Chlamydia-positive women, resulting in a T helper 2 response. On stimulation of peripheral blood mononuclear cells (PBMC) obtained from Chlamydia-positive women with the chlamydial antigen, the median levels of IL-10, IL-12 and IFN-gamma were higher than in controls, but the differences were not significant. Our study suggests that the mucosal immune responses towards Chlamydia trachomatis are different from those of PBMCs and are more helpful in understanding the cytokine responses in the female genital tract during chlamydial infection.     

Immunology of Chlamydia infection: implications for a Chlamydia trachomatis vaccine

Sexually transmitted Chlamydia trachomatis infections are a serious public-health problem. With more than 90 million new cases occurring annually, C. trachomatis is the most common cause of bacterial sexually transmitted disease worldwide. Recent progress in elucidating the immunobiology of Chlamydia muridarum infection of mice has helped to guide the interpretation of immunological findings in studies of human C. trachomatis infection and has led to the development of a common model of immunity. In this review, we describe our current understanding of the immune response to infection with Chlamydia spp. and how this information is improving the prospects for development of a vaccine against infection with C. trachomatis.     

Role of cervical dendritic cell subsets,co-stimulatory molecules,cytokine secretion profile and beta-estradiol in development of sequalae to Chlamydia trachomatis infection

Background  

Chlamydia trachomatis infection of the female genital tract can lead to serious sequelae resulting in fertility related disorders. Little is known about the mechanism leading to Chlamydia induced pathology and factors responsible for it. As only some of the women develops reproductive disorders while majority of the women clears infection without any severe sequalae, mucosal immune response in women with or without fertility disorders was studied to identify factors which may lead to final clinical outcome of chlamydial infection.     

A predominant role for antibody in acquired immunity to chlamydial genital tract reinfection

Acquired immunity to murine Chlamydia trachomatis genital tract reinfection has long been assumed to be solely dependent on cell-mediated immunity. However, in this study, we identify a previously unrecognized protective role for Ab. Immunity develops in Ab-deficient mice following the resolution of primary chlamydial genital infection. Subsequent depletion of CD4+ T cells, but not CD8+ T cells, in those immune Ab-deficient mice before secondary infectious challenge, resulted in an infection that did not resolve. Passive immunization with immune (convalescent) serum conferred a marked level of protective immunity to reinfection, which was characterized by a striking decrease in bacterial shedding, from >100,000 inclusion forming units to fewer than 10 inclusion forming units, and a shortened duration of infection. Furthermore, mAbs to the chlamydial major outer membrane protein and LPS conferred significant levels of immunity to reinfection and reduced chlamydial shedding by >100-fold. Anti-heat shock protein 60 mAb had no protective effect. In contrast to the marked protective efficacy of immune serum on reinfection, the course of primary infection was essentially unaltered by the passive transfer of immune serum. Our results convincingly demonstrate that Abs contribute importantly to immunity to chlamydial genital tract reinfection, and that Ab-mediated protection is highly dependent on CD4+ T cell-mediated adaptive changes that occur in the local genital tract tissues during primary infection. These results impact our understanding of immunity to chlamydial genital infection and may provide important insight into vaccine development.     

Antigen-specific CD8+ T cells respond to Chlamydia trachomatis in the genital mucosa

Following sexual transmission, Chlamydia trachomatis specifically targets genital tract epithelial cells. Because epithelial cells are readily recognized by CD8+ T cells, the response of CD8+ T cells to Chlamydia infection has been explored in a number of studies. It has been shown that CD8+ T cells are present in the genital tracts of mice following C. trachomatis infection, but the specificity of these T cells has remained undefined. To determine whether Chlamydia-specific CD8+ T cells migrate to the genital tract in response to Chlamydia infection, we generated retrogenic mice that express a TCR specific for a Chlamydia-specific T cell Ag CrpA. T cells from the retrogenic mice were transferred into naive recipient animals to increase the frequency of Chlamydia-specific T cells to a level at which they could be tracked during primary infection. We observed that the Chlamydia-specific retrogenic T cells proliferated in lymph nodes draining the genital tract in response to genital infection with C. trachomatis. Furthermore, we found that these cells acquired the ability to produce IFN-gamma and migrated into the genital mucosa of the infected mice.     

GM-CSF transgene-based adjuvant allows the establishment of protective mucosal immunity following vaccination with inactivated Chlamydia trachomatis

Cellular and humoral immune responses induced following murine Chlamydia trachomatis infection confer almost sterile protection against homologous reinfection. On the other hand, immunization with inactivated organism induces little protective immunity in this model system. The underlying mechanism(s) that determines such divergent outcome remains unclear, but elucidating the mechanism will probably be important for chlamydial vaccine development. One of the distinct differences between the two forms of immunization is that chlamydia replication in epithelial cells causes the secretion of a variety of proinflammatory cytokines and chemokines, such as GM-CSF, that may mobilize and mature dendritic cells and thereby enhance the induction of protective immunity. Using a murine model of C. trachomatis mouse pneumonitis lung infection and intrapulmonary adenoviral GM-CSF transfection, we demonstrate that the expression of GM-CSF in the airway compartment significantly enhanced systemic Th1 cellular and local IgA immune responses following immunization with inactivated organisms. Importantly, immunized mice had significantly reduced growth of chlamydia and exhibited less severe pulmonary inflammation following challenge infection. The site of GM-CSF transfection proved important, since mice immunized with inactivated organisms after GM-CSF gene transfer by the i.p. route exhibited little protection against pulmonary challenge, although i.p. immunization generated significant levels of systemic Th1 immune responses. The obvious difference between i.p. and intrapulmonary immunization was the absence of lung IgA responses following i.p. vaccination. In aggregate, the findings demonstrate that the local cytokine environment is critical to the induction of protective immunity following chlamydial vaccination and that GM-CSF may be a useful adjuvant for a chlamydial vaccine.     

Plasmid-deficient Chlamydia muridarum fail to induce immune pathology and protect against oviduct disease

Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection in the world. In women, genital infection can cause endometritis and pelvic inflammatory disease with the severe sequelae of ectopic pregnancy or infertility. Chlamydia sp. do not damage tissues directly, but induce an injurious host inflammatory response at the infected site. In the murine model of genital disease with Chlamydia muridarum, TLR2 plays a role in both early production of inflammatory mediators and development of chronic oviduct pathology. We report the results of studies with plasmid-cured C. muridarum mutants that retain the ability to infect the murine genital tract, but fail to cause disease in the oviduct. These mutants do not stimulate TLR2-dependent cytokine production in mice, nor in innate immune cells or epithelial cells in vitro. They induce an effective Th1 immune response, with no evidence for Th1-immune-mediated collateral tissue damage. Furthermore, mice previously infected with the plasmid-deficient strains are protected against oviduct disease upon challenge with virulent C. muridarum. If plasmid-cured derivatives of human C. trachomatis biovars exhibit similar phenotypic characteristics, they have the potential to serve as vaccines to prevent human disease.