Biology and Function of anti-HSV CD8 T Cells

抗 HSV CD8 T 细胞的生物学和功能

• 批准号: 7002674
• 负责人: STEPHEN ROBERT JENNINGS
• 金额: $ 31.03万
• 依托单位: DREXEL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7002674
• 关键词: Biology; Function; anti; HSV; CD8

DESCRIPTION (provided by applicant): Current concepts of the establishment and maintenance of long-term T cell memory propose that memory T cells are derived from a small; surviving subpopulation of effector T cells. Using a model of cutaneous HSV-1 infection in C57BL/6 mice, we have found that the ability to control infection is highly dependent upon the presence of HSV-1-specific CD4+ and CD8+ T cells, with the principal role being played by CD8+ T cells expressing cytolytic function and able to synthesize interferon-gamma (IFN-gamma). The ability to express CTL function was intimately linked with the increased expression of the IL-2 receptor alpha-chain, CD25. This observation lead to the conclusion that expression of high levels of CD25 was mandatory for the expression of HSV-specific CTL activity. However, a subpopulation of CD8+ T cells, present both within the draining regional lymph node and within the spleen during the early phase of the response to infection, has been identified. These cells synthesize IFN-gamma following antigenic stimulation in vitro without expressing elevated levels of CD25. In all other aspects, these CD8+ T cells have all of the characteristics of activated cells, suggesting that they may represent a population of effector cells able to synthesize only cytokines rather than express perforin-dependent CTL function, or may be the direct progenitors of memory CD8+ T cells. The hypothesis to be addressed is that this CD8+ T cell subpopulation represents a lineage of cells able to enter directly into the memory pool without proceeding through the full activation program to attain CTL function. Five specific aims will be studied. In Aim 1, the acquisition of in vivo cytolytic and cytokine synthetic functions of the CD8+ T cell subpopulations will be analyzed in detail throughout the course of the initial response to infection. Also, defined CD8+ T cells will be transferred to recipient animals, and the functions of the progeny determined. In Aim 2, the ability of this subpopulation to contribute to long-term memory will be assessed by adoptive transfer into appropriate recipient mice. This ability will be compared directly with "authentic" memory CD8+ T cells obtained from long-term convalescent mice. Aim 3 will address the activation status and function of the distinct CD8+ T cell subpopulations using a newly developed transgenic model, through the analysis of important signaling mediators, and the ability of the cells to persist as determined by measuring the percentage of apoptotic cells and the expression of anti-apoptotic molecules. Aim 4 will determine the phenotypic characteristics of the distinct CD8+ T cells to understand the molecular basis for differences in the migratory patterns in vivo. Aim 5 will address the role of different cytokine species in the clonal expansion and differentiation of the distinct CD8+ T cells, with focus given to the role of cytokines responsible for proliferation and differentiation. Overall, the proposal will determine whether the CD8+ CD25neg T cells contribute to memory, are a distinct subpopulation of effector cells with unique characteristics, or a developmental dead end. Greater insight into CD8 T cell biology will result from these studies.

描述（由申请人提供）：目前关于长期 T 细胞记忆的建立和维持的概念提出，记忆 T 细胞源自小细胞；幸存的效应 T 细胞亚群。使用 C57BL/6 小鼠皮肤 HSV-1 感染模型，我们发现控制感染的能力高度依赖于 HSV-1 特异性 CD4+ 和 CD8+ T 细胞的存在，其中发挥主要作用的是表达细胞溶解功能并能够合成干扰素-γ (IFN-γ) 的 CD8+ T 细胞。表达 CTL 功能的能力与 IL-2 受体 α 链 CD25 表达的增加密切相关。这一观察结果得出这样的结论：高水平的 CD25 表达对于 HSV 特异性 CTL 活性的表达是必需的。然而，在感染反应的早期阶段，存在于引流区域淋巴结和脾脏中的 CD8+ T 细胞亚群已被鉴定出来。这些细胞在体外抗原刺激后合成 IFN-γ，但不表达升高水平的 CD25。在所有其他方面，这些 CD8+ T 细胞具有活化细胞的所有特征，表明它们可能代表一群只能合成细胞因子而不是表达穿孔素依赖性 CTL 功能的效应细胞，或者可能是记忆 CD8+ T 细胞的直接祖细胞。要解决的假设是，这种 CD8+ T 细胞亚群代表了能够直接进入记忆池的细胞谱系，而无需通过完整的激活程序来获得 CTL 功能。将研究五个具体目标。在目标 1 中，将在感染的初始反应过程中详细分析 CD8+ T 细胞亚群体内溶细胞和细胞因子合成功能的获得。此外，确定的 CD8+ T 细胞将被转移到受体动物体内，并确定后代的功能。在目标 2 中，将通过过继转移到适当的受体小鼠中来评估该亚群对长期记忆的贡献能力。这种能力将直接与从长期恢复期小鼠获得的“真实”记忆 CD8+ T 细胞进行比较。目标 3 将使用新开发的转基因模型，通过分析重要的信号传导介质来解决不同 CD8+ T 细胞亚群的激活状态和功能，并通过测量凋亡细胞的百分比和抗凋亡分子的表达来确定细胞持续存在的能力。目标 4 将确定不同 CD8+ T 细胞的表型特征，以了解体内迁移模式差异的分子基础。目标 5 将解决不同细胞因子种类在不同 CD8+ T 细胞的克隆扩增和分化中的作用，重点关注负责增殖和分化的细胞因子的作用。总体而言，该提案将确定 CD8+ CD25neg T 细胞是否有助于记忆、是具有独特特征的独特效应细胞亚群，还是发育的死胡同。这些研究将带来对 CD8 T 细胞生物学的更深入的了解。