Development of a Chlamydia trachomatis Vaccine in an Outbred Pre-exposed Swine Animal Model

沙眼衣原体(Ct)是最常见的细菌性性传播病原体，可导致异位 怀孕和不孕。抗生素可以治愈感染但不能改善疾病，疫苗迫在眉睫 需要的。临床前动物研究的成功是疫苗进入人类临床试验的关键。猪是 负担得起，具有高度生物学相关性，是流行病原体猪衣原体(Cs)-a的自然宿主 与沙眼衣原体密切相关的衣原体种类。猪也容易感染Ct；保护CD4T细胞免受Cs前病毒的影响 暴露的猪对CT有交叉反应。这种交叉反应使预先接触Cs的猪成为一个非常有价值的动物模型 对于CT疫苗的开发：Cs预暴露的近交猪的疫苗可以模拟CT疫苗的预接种 暴露人群--临床III期CT疫苗接种试验的目标人群。凯瑟尔博士在 在Cs预暴露的猪中进行Cs和CT疫苗接种和挑战试验，并对CT进行详细分析 感染和免疫力。我们的长期目标是使用这种模式来开发CT疫苗，并将这种模式提供给 其他研究人员作为CT疫苗检测平台。这项研究有两个主要目标：使用预先接触Cs的猪来 利用新的疫苗配方和CT抗原开发CT疫苗候选，并提供深入的 了解保护性疫苗诱导的免疫机制。 这项研究分为三个阶段：第一阶段将确定免疫原性最强的肠外/粘膜，Prime/ 使用纳米乳剂中的全细胞灭活CT或辅以TriAdj的增强疫苗接种策略 佐剂。然后，第二阶段将使用最具免疫原性的疫苗接种策略来确定 已证实的和新的抗原组合-可能是MOMP、CFAMP、OmcB和Pgp3。疫苗的免疫原性和 体液和细胞介导的免疫反应将被系统地和局部地使用状态分析。 ART技术包括多肽抗体ELISA、多色T细胞流式细胞术、组织清除 结合荧光免疫组织化学和单细胞RNAseq分析适应性T细胞。 这前两个阶段将开发我们的候选疫苗-最具免疫原性的疫苗接种策略和Ct 抗原组合。在第三阶段，我们将在两个阶段测试该候选疫苗的效力和免疫原性 相同的动物试验，证明了评估我们的CT候选疫苗的严密性和重复性。 这项研究将在三个方面为进一步的CT疫苗研究和人类健康做出贡献：i)它将改善我们的 了解与预防CT相关的免疫反应；II)将开发一种新的CT疫苗 3)它将提供一项原则证明疫苗接种研究，以全面建立Cs预先暴露的猪模型。 这种高度相关的大型动物模型可以用来测试新的候选方案并改进现有的方案 目标是开发一种疫苗，使人类产生无菌免疫力。

Chlamydia trachomatis (Ct) is the most frequent bacterial sexually transmitted pathogen, and can lead to ectopic pregnancy and infertility. Antibiotics cure infection but may not ameliorate disease and a vaccine is urgently needed. Success in preclinical animal studies is essential for vaccines to move to human clinical trials. Pigs are affordable, highly biologically relevant, and the natural host to the prevalent pathogen Chlamydia suis (Cs) – a chlamydia species closely related to Ct. Pigs are also susceptible to Ct; and protective CD4 T cells from Cs pre- exposed pigs cross-react to Ct. This cross-reaction makes Cs pre-exposed pigs a highly valuable animal model for Ct vaccine development: Vaccination of Cs-pre-exposed outbred pigs can simulate Ct vaccination of Ct pre- exposed humans – the target population of clinical phase III Ct vaccination trials. Dr. Kaeser has expertise in performing Cs and Ct vaccination and challenge trials in Cs pre-exposed pigs and in detailed analyses of Ct infection and immunity. Our long-term goal is to use this model to develop Ct vaccines and to offer the model to other researchers as a Ct vaccine testing platform. This study has two main goals: Use Cs pre-exposed pigs to develop a Ct vaccine candidate with novel vaccine formulations and Ct antigens, and provide an in-depth understanding of protective vaccine-induced immune mechanisms. The study is divided into three phases: Phase I will determine the most immunogenic parenteral/mucosal, prime/ boost vaccination strategy using whole-cell inactivated Ct either in a nanoemulsion or adjuvanted with the TriAdj adjuvant. Phase II will then use the most immunogenic vaccination strategy to determine the immunogenicity of proven and novel antigen combinations – likely MOMP, CFAMP, OmcB, and pgp3. Vaccine immunogenicity and the humoral and cell mediated immune responses will be analyzed both systemically and locally using state-of- the art technologies including multi-peptide antibody ELISAs, multi-color T cell flow cytometry, tissue clearance in combination with fluorescent immunohistochemistry and single-cell RNAseq analyses of adaptive T cells. These first two phases will develop our vaccine candidate - the most immunogenic vaccination strategy and Ct antigen combination. In Phase III, we will test the efficacy and immunogenicity of this vaccine candidate in two identical animal trials, demonstrating rigor and reproducibility to evaluate our Ct vaccine candidate. This study will contribute in three ways to further Ct vaccine research and human health: i) It will improve our understanding of the immune response relevant for protection against Ct; ii) it will develop a novel Ct vaccine candidate; iii) it will provide a proof-of-principle vaccination study to fully establish the Cs pre-exposed pig model. This highly relevant large animal model can be used to test new candidates and improve on current regimens with the goal to develop a vaccine that results in sterilizing immunity in humans.