T-Cell Quality and Protective Immunity in a Murine Scrub Typhus Model

鼠恙虫病模型中的 T 细胞质量和保护性免疫

• 批准号: 9169476
• 负责人: LYNN SOONG
• 金额: $ 23.25万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-24 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9169476
• 关键词: Acute; Address; Adjuvant; Animal Model; Antibodies; Antigens; Apoptosis; Apoptotic; Arts; Asia; Attenuated; B-Lymphocytes; Bacteria; Biological Assay; Blood; Blood Vessels; Brain; CD4 Positive T Lymphocytes; CD8B1 gene; CXCL9 gene; Cells; Cellular Immunity; Clinical; Communicable Diseases; DNA; DNA Vaccines; Data; Dendritic Cells; Disease; Disease Outcome; Dose; Emerging Communicable Diseases; Endothelial Cells; Epitopes; Equilibrium; Failure; Flow Cytometry; Frequencies; Goals; Granulocyte-Macrophage Colony-Stimulating Factor; Homologous Gene; Human; Human Resources; Immune; Immune response; Immunity; Immunization; Immunologic Markers; In Vitro; Inbred C3H Mice; Infection; Interferons; Interleukin-10; Interleukin-12; Interleukin-13; Interleukin-2; Interleukin-4; Kidney; Kinetics; Knowledge; Life; Link; Liver; Lung; Measures; Messenger RNA; Mites; Modeling; Molecular; Mus; Onset of illness; Organ; Orientia tsutsugamushi; Pathogenesis; Pathology; Pathway interactions; Peptides; Population; Production; Progressive Disease; Proteins; Public Health; Recombinant Proteins; Research; Risk; Scrub Typhus; Serum; Spleen; Staging; T cell response; T-Cell Activation; T-Lymphocyte; TNF gene; Testing; Time; Tissues; Training; Vaccination; Vaccines; Variant; Work; anthrax lethal factor; bacterial lysate; base; biosafety level 3 facility; cell type; cytokine; design; innovation; monocyte; mortality; mouse model; neglect; pathogen; response; synthetic peptide; tool; vaccine candidate; vaccine development

Scrub typhus is a life-threatening disease caused Orientia tsutsugamushi, a LPS-negative bacterium that replicates preferentially in endothelial cells and monocytes. Approximately one million people are infected every year; about one third of the world's population is at risk of infection. There is no effective vaccine for this infection; information on disease pathogenesis and T cell immunity is limited. To address these challenges in this research field, we have developed C57BL6 mouse models that can mimic pathological features of human scrub typhus. We found that lethal infection was linked to type 1-biased immune responses, which correlated with excessive cellular apoptosis and vascular damage in multiple organs. In addition, we have identified the top vaccine candidates (p47 and p56) and their protective fragments from extensive studies of a panel of Orientia major antigens/formulas against homologues and heterologous challenges in outbred mice. The goal of this study is to examine how T cell responses control protective and pathogenic immune responses during infection with O. tsutsugamushi Karp, the most prevalent strain for human infections. Our central hypothesis is that appropriate T cell priming, through multi-variant vaccines or non-lethal infection, will help elicit a balanced immunity against bacterial spread, acute tissue damage and severe scrub typhus. Aim 1 will test that a multi-variant DNA vaccine platform can protect B6 mice against severe scrub typhus through the stimulation of a balanced activation of T- and B-cell immunity. At different stages of immunization and lethal challenge, we will evaluate tissue bacterial loads, pathological changes, as well as the kinetics and levels of host immune responses. Aim 2 will test the hypothesis that a progressive loss of T cells, especially Ag-specific CD8+ T cells, is the underlying mechanism for endothelial damage and contributing factor for lethal infection. We will use synthetic peptides that represent four predicted T epitopes and recombinant proteins to estimate cytokine production in re-call assays, as well as the frequency and fate of cytokine-secreting T cells. In vitro data will be integrated with those from immunostaining of apoptotic cells in the spleen and other organs. This vaccine- based, T cell-focused study endorses synergy among research teams (each with unique expertise); it utilizes the state-of-art ABSL3/BSL3 facilities at UTMB. The long-term goal of this study is to examine the potential of a multi-variant DNA vaccine platform and protective cellular immunity for the control of scrub typhus. Experiential evidence for a balanced T-cell activation in an immune-protected host would be particularly important, given the current status and gap in this neglected emerging disease. This timely study will have a broad implication for other intracellular pathogens.

Scrub Typhus是一种威胁生命 在内皮细胞和单核细胞中优先复制。大约一百万人被感染 每年;世界大约三分之一的人口有感染的风险。没有有效的疫苗 感染;疾病发病机理和T细胞免疫的信息受到限制。解决这些挑战 在研究领域，我们开发了C57BL6小鼠模型，可以模仿人类的病理特征 磨砂鼠伤寒。我们发现致命感染与1型偏置免疫反应有关，该反应相关 多个器官的细胞凋亡过多和血管损伤。此外，我们已经确定了 顶级疫苗候选物（P47和P56）及其保护性碎片，从一组小组中进行了广泛研究 东方针对近代小鼠的同源物和异源挑战的主要抗原/配方。目标 这项研究的是检查T细胞反应如何控制保护性和致病性免疫反应 O. tsutsugamushi Karp感染，这是人类感染最普遍的菌株。我们的中心假设 是否通过多变体疫苗或非致命感染来帮助引起适当的T细胞启动 平衡的免疫力抵抗细菌扩散，急性组织损伤和严重的磨砂鼠伤寒。 AIM 1将测试 多变量的DNA疫苗平台可以通过刺激保护B6小鼠免受严重的磨砂伤害 T-和B细胞免疫的平衡激活。在免疫和致命挑战的不同阶段，我们 将评估组织细菌负荷，病理变化以及宿主免疫的动力学和水平 回答。 AIM 2将检验以下假设：T细胞逐渐丧失，尤其是Ag特异性CD8+ T细胞， 是内皮损伤的基本机制和致死感染的促成因素。我们将使用 代表四个预测的T表位和重组蛋白的合成肽估计细胞因子 重新呼叫分析以及细胞因子分泌T细胞的频率和命运。体外数据将是 与脾脏和其他器官中凋亡细胞免疫染色的人集成。这种疫苗 - 以T细胞为中心的研究认可研究团队之间的协同作用（每个都有独特的专业知识）；它利用 UTMB的最先进的ABSL3/BSL3设施。这项研究的长期目标是检查 多变量的DNA疫苗平台和用于控制磨砂鼠伤寒的保护性细胞免疫。 尤其是在受到免疫保护宿主中平衡的T细胞激活的经验证据尤其是 重要的是，考虑到这种被忽视的新兴疾病的当前状态和差距。这项及时的研究将有一个 对其他细胞内病原体的广泛意义。