Immunity To Chlamydial Infection

对衣原体感染的免疫力

• 批准号: 6506921
• 负责人: HARLAN D CALDWELL
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6506921
• 关键词: Chlamydia trachomatis; bacterial antigens; bacterial vaccines; bactericidal immunity; biotechnology; chlamydial disease; disease /disorder model; laboratory mouse; mucosal immunity; vaccine development

The purpose of this work is to define the immunological basis that mediates protective immunity against Chlamydia trachomatis infection of the female genital tract. The long-term goal is to then use this information to develop a safe and efficacious vaccine against chlamydial caused sexually transmitted diseases (STD. The project involves the study of immunity in a murine model of chlamydial infection of the female genital tract. The goal of the work is to identify mechanisms of protective immunity and protective antigens, information that then can used to formulate novel vaccines to test in this pre-clinical model. The long-range goal is to move the most promising of these vaccines to human clinical trials to assess their safety and efficacy in preventing chlamydial STDs. Past studies from this laboratory using gene knock out mice, adoptive transfer of immune T cells, and in vivo depletion of T cell subsets strongly implicate CD4+ Th1 cell mediated immunity as the major protective arm of the immune response against chlamydial genital infection. Conversely, CD8+ T cells, gamma/delta T cells, and antibodies play only a limited role in mediating protective immunity. We have continued studies along these lines to further define effector function(s) of CD4+ Th1 mediated immunity and lymphocyte homing to the genital mucosal. Our findings do not support a role for IFN-gamma, TNF-alpha, iNOS, or Fas mediated apoptopic killing in protective anti-chlamydial mediated T cell immunity. Homing studies implicate both systemic and mucosal integrins and their cognate receptors in lymphocyte homing to the genital mucosa. All attempts to generate protective CD4+ Th1 anti-chlamydial immunity at the genital mucosa using conventional DNA and recombinant antigen vaccine approaches have failed. Infection of the genital tract, or other mucosal sites, is the only highly efficacious way of generating protective immunity against chlamydial genital re-challenge. Because of the difficulty in vaccinating against chlamydial genital infection we have undertaken a novel albeit unconventional approach to chlamydial vaccine development. This approach utilizes adoptive transfer of autologous dendritic cells (DC) pulsed ex vivo with intact non-viable chlamydial organisms. Our results show that in vitro grown DC efficiently phagocytose inactivated chlamydiae. Chlamydial-pulsed DC, but not DC pulsed with inert latex beads, up-regulate the expression of class II, and the T cell co-stimulatory molecules CD40 and CD86. Chlamydial-pulsed DC also up-regulate the expression of T cell differentiating cytokines IL-6, IL-10, IL-12, and TNF-alpha and the chemokines; MIP-3, MIP-1, IP-10, and MCP-1. Chlamydial-pulsed DC were found to be highly efficient in presenting chlamydial antigen(s) to infection sensitized protective CD4+ Th1 cells. Mice adoptively immunized with chlamydial-pulsed DC produced a strong chlamydial specific Th-1 biased immune response. Moreover, immunized mice were found to be as immune to chlamydial genital challenge as post-infection immune animals. Thus, ex vivo antigen pulsed DC represent a very powerful approach for the study of protective immunity to chlamydial infection of the genital mucosa. The use of ex vivo antigen pulsed DC will provide a way to identify chlamydial protective antigens and key immune effector functions that elicit protective immunity at the genital mucosa. Future studies will focus on using DC pulsed ex vivo with DNA based or recombinant protein antigens. These studies should yield information important to the development of more conventional vaccines for the prevention of chlamydial STDs.

这项工作的目的是确定介导对女性生殖道沙眼衣原体感染的保护性免疫的免疫学基础。长期目标是利用这些信息开发一种安全有效的疫苗，对抗衣原体引起的性传播疾病(STD)。该项目涉及对女性生殖道衣原体感染小鼠模型的免疫研究。这项工作的目标是确定保护性免疫和保护性抗原的机制，然后可以用这些信息来研制新的疫苗，在这个临床前模型中进行测试。长期目标是将这些疫苗中最有希望的疫苗转移到人体临床试验，以评估它们在预防衣原体性病方面的安全性和有效性。该实验室过去使用基因敲除小鼠、免疫T细胞过继转移和体内T细胞亚群耗尽的研究强烈表明，CD4+Th1细胞介导的免疫是对抗衣原体生殖道感染的免疫反应的主要保护臂。相反，CD8+T细胞、伽马/德尔塔T细胞和抗体在调节保护性免疫中的作用有限。我们继续沿着这些思路进行研究，以进一步确定CD_4+Th1介导的免疫的效应功能(S)和淋巴细胞归巢到生殖器粘膜。我们的发现不支持干扰素-γ、肿瘤坏死因子-α、诱导型一氧化氮合酶或Fas介导的细胞凋亡在保护抗衣原体介导的T细胞免疫中的作用。归巢研究表明，全身和粘膜整合素及其同源受体与淋巴细胞归巢到生殖器粘膜有关。使用常规DNA和重组抗原疫苗方法在生殖器粘膜产生保护性CD4+Th1抗衣原体免疫的所有尝试都失败了。生殖道或其他粘膜部位的感染是产生保护性免疫以抵御衣原体生殖器再次攻击的唯一高效方式。由于接种衣原体生殖器感染疫苗的困难，我们采用了一种新的、尽管非常规的方法来开发衣原体疫苗。这种方法利用过继转移自体树突状细胞(DC)体外冲击与完整的非存活衣原体生物体。我们的结果表明，体外培养的DC能有效地吞噬灭活衣原体。衣原体冲击的DC，而不是惰性乳胶微珠冲击的DC，上调了II类分子以及T细胞共刺激分子CD40和CD86的表达。衣原体致敏的DC还可上调T细胞分化因子IL-6、IL-10、IL-12和TNF-α以及趋化因子MIP-3、MIP-1、IP-10和MCP-1的表达。衣原体致敏的DC能高效地将衣原体抗原(S)递送给感染致敏的保护性T细胞。衣原体致敏DC过继免疫的小鼠产生强烈的衣原体特异性Th-1偏向免疫应答。此外，免疫小鼠对衣原体生殖器攻击的免疫力与感染后免疫动物相同。因此，体外抗原致敏的DC是研究生殖器黏膜衣原体感染保护性免疫的一种非常有效的方法。体外抗原致敏DC的使用将提供一种识别衣原体保护性抗原和关键免疫效应器功能的方法，从而在生殖器粘膜引起保护性免疫。未来的研究将集中在将DC冲击的体外与DNA为基础的或重组蛋白抗原。这些研究应该会产生对开发更传统的预防衣原体性病疫苗很重要的信息。