Role of T reg in live vaccination against leishmaniasis

T reg 在利什曼病活疫苗接种中的作用

• 批准号: 6894731
• 负责人: Susana Mendez
• 金额: $ 7.3万
• 依托单位: GEORGE WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-15 至 2005-12-02
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6894731
• 关键词: CpG islands; Leishmania major; T lymphocyte; active immunization; antigen presentation; cell migration; cellular immunity; cytokine; dendritic cells; immune response; immunomodulators; interleukin 6; laboratory mouse; leishmaniasis; live vaccine; pharmacokinetics; phenotype; ulcer; zoonosis

DESCRIPTION (provided by applicant): Leishmania major (Lm) is the causative agent of zoonotic cutaneous leishmaniasis (ZCL), the most widely distributed form of ZCL in the Old World. The inoculation of live, non-attenuated Lm to produce a lesion that heals (leishmanization) is to date the only vaccine against leishmaniasis proven effective in humans. We have developed a live vaccine containing live Lm and immonostimulatory oligodeoxynucleotides (CpG ODNs) that ameliorates or abolish lesion due to vaccination and confers long term protection in the murine model. Our goal is to determine the role of regulatory T cells (Treg) in live vaccination against Lm. The specific hypothesis is that the absence of lesions due to live vaccination in the presence of CpG ODNs is caused by a downreagulation of Treg fuction caused by activation of dendritic cells (DCs) that leads to an enhanced immune response. We based this hypothesis on the observations that 1) CpG ODNs are known to activate DC function 2) Treg control the intensity of immune response by suppressing effector function and 3) DCs release IL-6 after CPG ODNs stimulation that partially suppress Treg function. Addition of CpG ODNs to live vaccination will stimulate DCs and therefore supersede Treg function, leading to an 1) enhanced effector immune response, 2) increased parasite killing and, thus, 3) absence of lesion due to vaccination. To prove that hypothesis, we present the following specific aims: 1. Define the relationship of CpG ODNs-activated APC and Treg in vitro. We will perform in vitro studies using DCs pulsed with live vaccine conditions and each of the components and determine their effect on DCs and Treg incubated with such DCs. 2. Characterize the in vivo role of CpG ODNs in modulating Treg function on the Lm/C57BI/6 model. We will vaccinate mice and extract DCs and Treg at different time points to study their function and phenotype. We will use those cells to reconstitute RAG -/- and determine their phenotype.

描述（由申请人提供）：大型利什曼原虫（Lm）是人畜共患皮肤利什曼病（ZCL）的病原体，ZCL 是旧世界分布最广泛的 ZCL 形式。接种活的、非减毒的 Lm 以产生可治愈的病变（利什曼化）是迄今为止唯一被证明对人类有效的利什曼病疫苗。我们开发了一种含有活 Lm 和免疫刺激性寡脱氧核苷酸 (CpG ODN) 的活疫苗，可改善或消除疫苗接种引起的病变，并在小鼠模型中提供长期保护。我们的目标是确定调节性 T 细胞 (Treg) 在 Lm 活疫苗接种中的作用。具体的假设是，在存在 CpG ODN 的情况下，活疫苗接种不会造成损伤，这是由于树突状细胞 (DC) 活化导致 Treg 功能下调，导致免疫反应增强。我们基于以下观察结果提出这一假设：1）已知 CpG ODN 可以激活 DC 功能；2）Treg 通过抑制效应器功能来控制免疫反应的强度；3）DC 在 CPG ODN 刺激后释放 IL-6，部分抑制 Treg 功能。在活疫苗接种中添加 CpG ODN 将刺激 DC，从而取代 Treg 功能，从而导致 1) 增强效应免疫反应，2) 增加寄生虫杀伤力，从而 3) 消除因疫苗接种引起的病变。为了证明这一假设，我们提出以下具体目标： 1. 体外定义 CpG ODNs 激活的 APC 和 Treg 的关系。我们将使用在活疫苗条件下脉冲的 DC 和每种成分进行体外研究，并确定它们对与此类 DC 一起孵育的 DC 和 Treg 的影响。 2. 表征 CpG ODN 在 Lm/C57BI/6 模型上调节 Treg 功能的体内作用。我们会给小鼠接种疫苗，并在不同时间点提取DC和Treg来研究它们的功能和表型。我们将使用这些细胞重建 RAG -/- 并确定它们的表型。