Molecular Analysis of Human Naive and Memory T Cells

总结：本项目的目标是描述记忆淋巴细胞的分子特性，并阐明免疫记忆的机制。 我们研究人类外周血记忆和幼稚CD 4 + T细胞作为模型，因为它们的表型和功能特征。 记忆性CD 4 + T细胞表达CD 45 R 0，而初始CD 4 + T细胞表达CD 45 RA，其用作分离这两个亚群的基础。 评估全球基因表达的记忆细胞在休息和激活后，与na？我们使用cDNA微阵列分析了超过58，000个独特的人cDNA克隆，发现记忆和初始CD 4 + T细胞表达约22-27%的总克隆。 总的来说，记忆和初始CD 4 + T细胞在静息和活化后表达相似数量的基因。抑制细胞增殖的基因在静息细胞中高度表达，但在记忆和初始CD 4 + T细胞中刺激后均一致下调。相反，激活诱导基因的表达显示出梯度模式，其中mRNA水平与激活程度相关，并将记忆与幼稚细胞区分开来。 总之，我们的研究结果定义了记忆性CD 4 + T细胞在静息和激活后的转录性质，并确定了区分记忆性CD 4 + T细胞与幼稚CD 4 + T细胞反应的分子机制。 在全局分析的过程中，我们已经确定了超过170个已知的基因，其表达在激活后发生了显着变化。最近，我们已经将cDNA微阵列分析的mRNA水平的研究扩展到常规的北方和RT-PCR，以及选定基因的蛋白质水平。 目前，我们正在研究这些激活相关基因的时间变化及其在记忆和幼稚CD 4 + T细胞激活中的功能。

Summary: The goals of this project are to characterize the molecular identity of memory lymphocytes and to elucidate the mechanisms underlying immunological memory. We study human peripheral blood memory and naive CD4+ T cells as a model because they are phenotypically and functionally well characterized. Memory CD4+ T cells express CD45R0 while naive CD4+ T cells express CD45RA, which was used as the basis for isolation of these two subsets. To assess the global gene expression of memory cells at rest and after activation in comparison with na?ve cells using cDNA microarray, we analyzed over 58,000 unique human cDNA clones and found that memory and naive CD4+ T cells expressed about 22-27% of total clones. Overall, memory and naive CD4+ T cells express similar number of genes at rest and after activation. Genes that inhibit cellular proliferation are highly expressed in resting cells but are uniformly down-regulated after stimulation in both memory and naive CD4+ T cells. In contrast, the expression of activation-induced genes displays a gradient pattern in which the mRNA levels correlate with the degree of activation, and differentiate memory from naive cells. Together, our results defines the transcriptional nature of memory CD4+ T cells at rest and after activation, and identify a molecular mechanism that differentiates the response of memory CD4+ T cells from naive CD4+ T cells. In the process of global analysis, we have identified over 170 known genes whose expression was significantly changes after activation. Recently, we have extended the study of mRNA levels analyzed by cDNA microarray to conventional Northern and RT-PCR, as well as protein levels of selected genes. Currently, we are studying the temporal changes of these activation-related genes and their function in memory and naive CD4+ T cell activation.