ANALYSIS OF A NOVEL SUBSET OF HUMAN CD8+ MEMORY CELLS WITH STEM CELL QUALITIES

描述(由申请人提供)：本申请涉及广泛的挑战领域04，临床研究和特定挑战主题04-AI-102-人类对感染和免疫的免疫反应-通过现代免疫学方法和系统生物学进行剖析。 记忆T细胞的发育和维持是宿主对急性和持续性病毒感染反应的标志，也是传染病和癌症疫苗接种的主要目标。对小鼠和人类记忆T细胞的表型和功能的分析已经确定了两个广泛的长寿记忆细胞亚群，即中央记忆(TCM)和效应记忆(TEM)，前者由CD45O和CD62L的表达定义，后者由CD45RO的表达和CD62L的缺失定义。申请人实验室最近的工作已经在正常人中发现了静止记忆CD8+T细胞的一个子集，它表达细胞表面标记，使它们能够从更普遍的中医和透射电子显微镜亚群中分离出来，并且包括造血干细胞共享的分子。与大多数记忆T细胞相比，这些静止的记忆T细胞表现出更高的三磷酸腺苷结合盒(ABC)转运蛋白活性，快速外排荧光染料和化疗药物，并且在体外和体内对细胞毒化疗具有耐药性。高流出的T细胞具有不同的T细胞受体，含有针对持久性和急性病毒的T细胞，并有助于在接受化疗的个体中重新繁殖记忆T细胞。对分类纯化的记忆T细胞和NA细胞亚群进行的初步基因表达阵列表明，与大多数TM细胞和TN细胞相比，具有高外流能力的记忆T细胞亚群具有不同的转录谱。这项挑战拨款中的研究将提供关于这些新的人类抗原经历T细胞亚群的频率、功能特性和基因表达谱的详细数据库，并阐明它们在接种后的发展。这项工作的潜在影响涉及到提高我们对正常人和接受化疗或疫苗接种的人CD8+T细胞记忆持久性的机制的理解。这些研究对于阐明传染病和癌症疫苗可能引发的保护性免疫的性质具有重要意义，并可能为衰老过程中宿主对病原体的免疫完整性提供一个标记。目的：1.比较人记忆性CD8+T细胞CD161亚群中IL-18R、CD161lo、TN和中医的IL-18Rlo亚群的频率、转录水平及维持分化的因素。这项拟议的研究将确定CMHI和EMHI在正常成年人(18-80岁)中的频率，确定这些亚群在10名捐赠者中的转录谱，并比较CMHI和EMHI与各自的非流出性亚群以及与TN的功能特性。目的2.确定痘苗病毒初次或加强免疫是否能诱导痘苗病毒特异性CD8+CMHI和EMHI T细胞亚群的长期存活。在感染或接种后，这种新的IL18R亚群CD161hi病毒特异性T细胞可能形成的时间尚未确定。拟议的研究将检查远程接种牛痘疫苗的个体、最近接种牛痘疫苗的个体以及接受初级疫苗接种的牛痘病毒特异性T细胞的存在。 公共卫生相关性：记忆性T细胞的发展和维持是宿主对急性和持续性病毒感染反应的标志，也是传染病和癌症疫苗接种的主要目标。在确定记忆T细胞的质量属性方面取得的进展要少得多，特别是在人类身上。解决这些问题需要更多地了解组成人类记忆T细胞池的T细胞亚群，并应用新的方法来询问维持这些细胞的细胞和分子程序。这项挑战拨款中的研究将确定具有长寿命细胞特征的新型人类记忆T细胞亚群的频率、功能特性和基因表达谱，并阐明它们在接种后的发展。 这项工作的潜在影响涉及到提高我们对正常人和接受化疗或疫苗接种的人CD8+T细胞记忆持久性的机制的理解。

DESCRIPTION (provided by applicant): This application addresses broad Challenge Area 04, Clinical Research and specific Challenge Topic 04-AI-102 - The human immune response to infection and immunization - Profiling via modern immunologic methods and systems biology. The development and maintenance of memory T cells is a hallmark of the host response to acute and persistent viral infections and a major objective of vaccination for infectious diseases and cancer. Analysis of the phenotype and function of memory T cells in both mice and humans has identified two broad subsets of long-lived memory cells termed central memory (TCM), defined by expression of CD45O and CD62L; and effector memory (TEM), defined by expression of CD45RO and the absence of CD62L. Recent work in the applicant's lab has identified a subset of quiescent memory CD8+ T cells in normal individuals that express cell surface markers that enable their separation from the more prevalent TCM and TEM subsets, and includes molecules shared by hematopoietic stem cells. These quiescent memory T cells exhibit higher ATP binding cassette (ABC) transporter activity, rapidly efflux fluorescent dyes and chemotherapy drugs and are resistant to cytotoxic chemotherapy in vitro and in vivo compared with the majority of memory T cells. The high-effluxing T cells have a diverse T cell receptor repertoire, contain T cells specific for persistent and acute viruses, and contribute to repopulation of memory T cells in individuals who have received chemotherapy. Preliminary gene expression arrays performed on sort-purified subpopulations of memory and na¿ve T cells demonstrate that the subsets of memory T cells with high efflux capacity have a distinct transcriptional profile compared with the majority of TM cells, and with TN cells. The studies in this challenge grant will deliver a detailed database on the frequency, functional properties and gene expression profile of these novel subsets of human antigen experienced T cells, and elucidate their development after vaccination. The potential impact of this work relates to improving our understanding of the mechanisms responsible for the durability of human CD8+ T memory in normal individuals and those undergoing chemotherapy or vaccination. The studies have implications for elucidating the nature of protective immunity that might be elicited by vaccines for infectious diseases and cancer, and could provide a marker for the integrity of host immunity to pathogens in aging. The specific aims are: Aim 1. To compare the frequency, transcriptional profile and factors governing maintenance and differentiation of chemotherapy resistant IL-18R?hi CD161hi subsets of human memory CD8+ T cells with IL-18Rlo CD161lo subsets of TCM and TEM, and with TN. The proposed studies will determine the frequency of CMhi and EMhi in normal adult humans (age 18-80), determine the transcriptional profile of these subsets in ten donors, and compare the functional properties of CMhi and EMhi with the respective non-effluxing subsets and with TN. Aim 2. To determine if primary or booster vaccination of humans with vaccinia virus induces a longlived subset of vaccinia virus-specific CD8+ CMhi and EMhi T cells. The time after infection or vaccination when this novel subset of IL18R?hi CD161hi virus-specific T cells might develop has not been defined. The proposed studies will examine the presence of vaccinia virus specific T cells in individuals with remote vaccinia immunization, recent vaccinia boosting and in vaccinia na¿ve individuals receiving a primary vaccination. PUBLIC HEALTH RELEVANCE: The development and maintenance of memory T cells is a hallmark of the host response to acute and persistent viral infections and a major objective of vaccination for infectious diseases and cancer. Progress in defining the qualitative attributes of memory T cells that contribute to their longevity has been much less significant, particularly in humans. Addressing these issues requires a greater understanding of the subsets of T cells that make up the human memory T cell pool and the application of novel approaches to interrogate the cellular and molecular programs that maintain these cells. The studies in this challenge grant will determine the frequency, functional properties and gene expression profile of novel subsets of human memory T cells that have characteristics of long-lived cells, and elucidate their development after vaccination. The potential impact of this work relates to improving our understanding of the mechanisms responsible for the durability of human CD8+ T memory in normal individuals and those undergoing chemotherapy or vaccination.