Immunity To Chlamydial Infection

这项工作的目的是确定介导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来对抗衣原体引起的性传播疾病（STD）。该项目涉及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，这些信息然后可以用于制定新的疫苗，以在这种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进行人体临床试验，以评估其预防衣原体性传播疾病的安全性和有效性。本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细胞亚群耗竭进行的研究强烈暗示CD 4 + Th 1细胞介导的免疫是抵抗衣原体生殖器感染的免疫应答的主要保护臂。相反，CD 8 + T细胞、γ/δ T细胞和抗体在介导保护性免疫中仅发挥有限的作用。我们沿着这些路线继续研究，以进一步确定CD 4 + Th 1介导的免疫和淋巴细胞归巢生殖器粘膜的效应器功能。我们的研究结果不支持IFN-γ、TNF-α、iNOS或Fas介导的异位杀伤在保护性抗衣原体介导的T细胞免疫中的作用。归巢研究涉及全身和粘膜整合素及其同源受体淋巴细胞归巢生殖器粘膜。所有使用常规DNA和重组抗原疫苗方法在生殖器粘膜产生保护性CD 4 + Th 1抗衣原体免疫的尝试都失败了。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，我们已经采取了一种新的，尽管是非传统的方法来开发衣原体疫苗。该方法利用了用完整的非存活衣原体生物体离体脉冲的自体树突状细胞（DC）的过继转移。我们的研究结果表明，在体外生长的DC有效地吞噬灭活的衣原体。衣原体脉冲的DC，但不是DC脉冲与惰性乳胶珠，上调II类，和T细胞共刺激分子CD 40和CD 86的表达。衣原体脉冲的DC还上调T细胞分化细胞因子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。发现衣原体脉冲的DC在将衣原体抗原呈递给感染致敏的保护性CD 4 + Th 1细胞方面是高效的。用衣原体致敏DC过继免疫小鼠产生强烈的衣原体特异性Th-1偏向性免疫应答。此外，免疫小鼠被发现是免疫衣原体生殖器的挑战，感染后的免疫动物。因此，离体抗原脉冲的DC代表了一个非常强大的方法，用于生殖器粘膜的衣原体感染的保护性免疫的研究。使用离体抗原脉冲的DC将提供一种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子功能的方法。未来的研究将集中在使用DC脉冲离体与基于DNA或重组蛋白抗原。这些研究应产生重要的信息，以开发更传统的疫苗，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.