Control of cytotoxic T cell differentiation and activity

细胞毒性 T 细胞分化和活性的控制

• 批准号: 7017035
• 负责人: Martha Ann Alexander-Miller
• 金额: $ 28.03万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7017035
• 关键词: CD28 molecule; RNase protection assay; SDS polyacrylamide gel electrophoresis; T cell receptor; antigen presenting cell; biological signal transduction; cell differentiation; cytotoxic T lymphocyte; genetically modified animals; helper T lymphocyte; immunoprecipitation; interleukin 2; laboratory mouse; leukocyte activation /transformation; nucleic acid sequence; polymerase chain reaction; tissue /cell culture

The contribution of CDS cytotoxic T lymphocytes (CTL) to the eradication of viral infections has been well documented. Recent studies from our lab and others have demonstrated that the functional avidity of a CTL, as defined by the sensitivity to peptide antigen, is a major determinant of the efficacy for viral clearance in vivo. The mechanisms which control the avidity of an individual CTL, as well as the activation and expansion of high avidity CTL in vivo, are fundamental issues in immunology which have important implications for the design of vaccine constructs and immunotherapeutics. Presently, the mechanism by which avidity is established in an individual T cell is largely undefined. Further whether avidity is an inherent property or can be modulated in response to environmental signals is unknown. In our analysis of high and low avidity lines generated from TCR transgenic mice, we made the surprising observation that low avidity cells express CD8alpha/beta homodimers in addition to CD8alpha/beta heterodimers. Expression of CD8alphaa/alpha may reduce the efficiency with which these cells transduce TCR signals, given the reduced localization of CD8alpha/alpha and its associated kinase, Lck, to lipid raft resident TCR. Using sorted populations of cells from TCR transgenic mice, we have found that CD8P expression at the cell surface is regulated as a result of the level of peptide antigen encountered, consistent with the hypothesis that avidity in modulated by antigen encounter. In aim one we will address a number of critical questions regarding the control of avidity including how CDSalpha and beta expression are modulated by antigen encounter, when avidity becomes fixed in effector cells, how the level of peptide antigen alters the association of CDS with the TCR complex, and whether memory cells are capable of CDS modulation in response to the level of presented peptide antigen. Further expression of alpha and/or beta will be altered by retroviral transduction and CDS protein expression will be studied to determine how CDS expression is controlled and its result on function. In aim two we will extend our in vitro studies of the effect of differential antigen presentation to the in vivo activation of CD8+ T cells following viral infection. This will be accomplished through use of a panel of vaccinia viruses which result in high, intermediate, or low levels of presented antigen. The results from these studies will significantly increase of understanding of the control of functional avidity and the activation/expansion of high avidity cells in vivo and may provide novel insights into the design of improved vaccine strategies.

CDS细胞毒性T淋巴细胞（CTL）对根除病毒感染的贡献已得到充分证明。我们实验室和其他人的最新研究表明，由对肽抗原的敏感性所定义的CTL的功能亲和力是体内病毒清除功效的主要决定因素。控制单个CTL的亲戚的机制以及体内高流行病CTL的激活和扩展是免疫学中的基本问题，这些问题对疫苗构建体和免疫治疗学的设计具有重要意义。目前，在单个T细胞中建立亲和力的机制在很大程度上是不确定的。进一步的生动是固有的属性还是可以根据环境信号进行调制。在我们对高和分析中 从TCR转基因小鼠产生的低自发线，我们做出了令人惊讶的观察结果，即低自动细胞除了CD8Alpha/beta异二聚体外表达CD8Alpha/beta同型二聚体。鉴于CD8alpha/alpha及其相关激酶LCK的定位降低，CD8AlphaA/alpha的表达可能会降低这些细胞转导TCR信号的效率。使用TCR转基因小鼠的细胞群体分类的群体，我们发现在细胞表面的CD8P表达受到肽水平的调节 抗原遇到，与抗原相遇调节中的亲和力的假设一致。在AIM ONE中，我们将解决有关亲发控制的许多关键问题，包括CDSALPHA和BETA表达如何通过抗原相遇调节，当生效在效应细胞中固定时，肽抗原的水平如何改变CD与TCR复合物的关联以及对存储细胞的关联，以及是否能够对CDS调节CDS对响应的CDS调节。 α和/或β的进一步表达 将通过逆转录病毒转导改变，将研究CDS蛋白表达，以确定如何控制CDS表达及其对功能的结果。在目标二中，我们将扩展有关差异抗原呈递作用的体外研究，以便在病毒感染后的体内激活CD8+ T细胞的体内激活。这将通过使用一组疫苗病毒来实现，该病毒导致较高，中间或低水平的抗原。这些研究的结果将显着提高对功能亲和力控制的理解以及体内高自发细胞的激活/扩展，并可能提供新颖的。 深入了解改进的疫苗策略的设计。