MOLECULAR ANALYSIS OF HUMAN NAIVE AND MEMORY T CELLS

摘要：本项目旨在了解na？记忆，免疫记忆。作为实现这一目标的第一步，我们分析了人类幼稚和记忆CD4+ T细胞的基因表达谱，并确定了在一个群体中与另一个群体中差异表达的基因。人类CD4+初始T细胞和记忆T细胞是表型明确的亚群，即表达CD45RA的初始CD4+ T细胞和表达CD45R0的记忆CD4+ T细胞。我们采用免疫磁分离技术从外周血中分离出大量高纯度的幼稚细胞和记忆细胞。从幼稚T细胞和记忆T细胞中分离信使RNA，用于基因表达分析。利用基因芯片分析基因表达谱和差异表达基因。在估计的人类基因总数中，大约有一半（45000个）被分析，发现na？淋巴细胞和记忆性CD4+ T细胞表达约占总基因的15-20%。大约85%的表达基因在幼稚细胞和记忆细胞之间是相似的。以表达比为2作为差异表达标准，我们发现约有300个基因（占总表达基因的4%）在na？约740个基因（占总表达基因的9%）在记忆性CD4+ T细胞中差异表达。在这些基因中，已知的这些差异表达基因仅占5-10%，其中大多数是est。目前，我们正在通过Northern原位杂交和测序来表征这些差异表达基因。幼稚T细胞和记忆T细胞，cDNA微阵列，淋巴细胞活化，能量

Summary: The goal of this project is to understand the molecular basis of lymphocyte differentiation from na?ve to memory, and immunological memory. As the first step toward this goal, we have analyzed gene expression profiles of human naive and memory CD4+ T cells, and identified genes that are differentially expressed in one population over the other. Human CD4+ naive and memory T cells are phenotypically well defined subsets, i.e. naive CD4+ T cells expressing CD45RA and memory CD4+ T cells expressing CD45R0. We used immunomagnetic separation isolating large number of highly pure naive and memory cells from peripheral blood. Messenger RNA was isolated from naive and memory T cells and used for gene expression analysis. Gene expression profile and differentially expressed genes were analyzed by cDNA microarray. Approximately half of the estimated total human genes (45,000) were analyzed and found that na?ve and memory CD4+ T cells expressed about 15-20% of total genes. The levels of expression about 85% of the expressed genes are similar between naive and memory cells. Using an expression ratio of 2 as criteria of differential expression, we found that about 300 genes (4% of total expressed genes) that are differentially expressed in na?ve CD4+ T cells and about 740 genes (9% of total expressed genes) differentially expressed in memory CD4+ T cells. Among these genes, only 5-10% of these differentially expressed known genes and the majority of them are ESTs. Currently, we are characterizing these differentially expressed genes by Northern, in situ hybridization, and sequencing. - Naive and memory T cells, cDNA microarray, lymphocyte activation, anergy