Immunity To Chlamydial Infection

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研制一种安全有效的预防衣原体引起的性传播疾病的疫苗，该项目包括研究女性生殖道衣原体感染小鼠模型的免疫力。这项工作的目标是确定保护性免疫和保护性抗原的机制，这些信息可以用来制定新的疫苗，在临床前模型中进行测试。长期目标是将这些最有希望的疫苗转移到人体临床试验，以评估其在预防衣原体性传播疾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细胞亚群耗损的研究强烈暗示CD4+ Th1细胞介导的免疫是针对衣原体生殖器感染的免疫反应的主要保护臂。相反，CD8+ T细胞、γ / δ T细胞和抗体在介导保护性免疫中只发挥有限的作用。我们沿着这条路线继续研究，以进一步确定CD4+ Th1介导的免疫和淋巴细胞归巢到生殖器粘膜的效应功能。我们的研究结果不支持ifn - γ、tnf - α、iNOS或Fas介导的凋亡杀伤在抗衣原体介导的保护性T细胞免疫中的作用。归巢研究暗示了系统和粘膜整合素及其同源受体在淋巴细胞归巢生殖器粘膜中的作用。使用传统的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抗衣原体生殖器再次攻击的唯一高效方法。由于接种预防衣原体生殖器感染的疫苗很困难，我们采取了一种尽管非常规的新方法来开发衣原体疫苗。这种方法利用体外脉冲的自体树突状细胞（DC）与完整的非活的衣原体生物的过继性转移。结果表明，体外培养的DC能有效地吞噬灭活的衣原体。衣原体脉冲DC，而非惰性乳胶珠脉冲DC，上调II类和T细胞共刺激分子CD40和CD86的表达。衣原体脉冲DC也上调T细胞分化因子IL-6、IL-10、IL-12和tnf - α及其趋化因子的表达；MIP-3、MIP-1、IP-10和MCP-1。发现衣原体脉冲DC在将衣原体抗原呈递到感染致敏的保护性CD4+ Th1细胞方面效率很高。以衣原体脉冲DC过继免疫小鼠产生强烈的衣原体特异性Th-1偏向免疫反应。此外，免疫小鼠被发现对衣原体生殖器攻击具有与感染后免疫动物相同的免疫力。因此，体外抗原脉冲DC为研究生殖器粘膜衣原体感染的保护性免疫提供了一种非常有力的方法。体外抗原脉冲DC的使用将为鉴定衣原体保护性抗原和在生殖器粘膜引起保护性免疫的关键免疫效应功能提供一种方法。未来的研究将集中在体外DC脉冲与DNA或重组蛋白抗原的结合上。这些研究应提供重要的信息，以开发更常规的疫苗，以预防衣原体性传播疾病。

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.