Gene expression signature of in vitro activated CD8 T cells in response to antigen and B7-1 alone or along with IL-21

Differentiation of naive CD8 T cells into cytotoxic effector cells requires three distinct signals- antigen (signal 1), costimulation -B7-1 (signal 2) and cytokine, either interleukin-12, interferon-a/b, or IL-21 (signal 3). Interaction of naive CD8 T cells with antigen and B7-1 programs cell division and proliferation whereas the presence of cytokines- IL-12, IFNa/b or IL-21 promote survival, differentiation and memory establishment. In the absence of signal 3, the cells interacting with antigen/B7-1 undergo tolerance induction. Previous work had analyzed the regulation of mRNA expression changes induced by IL-12 and IFN-a and cells stimulated with antigen, B7-1 and cytokine by comparing mRNA expression levels in naïve CD8 T cells, cells stimulated with 2 signals (antigen and B7-1) (Agarwal, P.A., A. Raghavan, S.L. Nandiwada, J.M. Curtsinger, P.R. Bohjanen, D.L. Mueller and M.F. Mescher. Gene regulation and chromatin remodeling by IL-12 and Type I interferon in programming for CD8 T cell effector function and memory. J. Immunol. 183:1695-1704 (2009). PMCID: PMC2893405). That microarray data was deposited in the NCI GEO database and can be found at http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc_GSE15930. The objective of the current study was to carry out the same analysis to determine IL-21-dependent changes in mRNA expression in CD8 T cells responding to antigen and B7-1-dependent costimulation in the absence or presence of IL-21. The programming for development of function and memory in presence of signal 3 occurs over three days of initial stimulation, and antigen, B7-1 and either IL-12, IFNa/b or IL-21 must be present for most of this period to achieve maximal responses. We analyzed gene expression at 48 and 72 hours in cells stimulated in vitro with antigen and B7-1 alone or along with IL-21.

初始CD8 T细胞（naive CD8 T cells）分化为细胞毒性效应细胞需要三种不同信号：抗原（信号1）、共刺激分子B7-1（信号2），以及细胞因子——白细胞介素-12、干扰素-α/β或IL-21（信号3）。初始CD8 T细胞与抗原和B7-1的相互作用可启动细胞分裂与增殖，而IL-12、IFN-α/β或IL-21等细胞因子则可促进细胞存活、分化及记忆建立。若缺乏信号3，与抗原/B7-1相互作用的细胞会发生免疫耐受诱导。既往研究通过比较初始CD8 T细胞、经双信号（抗原与B7-1）刺激的细胞的信使核糖核酸（mRNA）表达水平，分析了IL-12与IFN-α诱导的mRNA表达变化，以及经抗原、B7-1与细胞因子共同刺激的细胞的基因表达调控规律（Agarwal, P.A., Raghavan, A., Nandiwada, S.L., Curtsinger, J.M., Bohjanen, P.R., Mueller, D.L. & Mescher, M.F. 《IL-12与I型干扰素在CD8 T细胞效应功能与记忆编程中的基因调控与染色质重塑》，J. Immunol. 183:1695-1704 (2009). PMCID: PMC2893405）。该微阵列（microarray）数据已存入NCI GEO数据库，可通过链接http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE15930获取。本研究旨在开展同类分析，以探究在存在或不存在IL-21的情况下，经抗原与B7-1依赖性共刺激的CD8 T细胞中，IL-21依赖性的mRNA表达变化。在信号3存在的条件下，功能与记忆发育的编程过程发生于初始刺激后的三天内，且此期间大部分时段需同时存在抗原、B7-1以及IL-12、IFN-α/β或IL-21，才能获得最大应答效应。我们对体外经抗原与B7-1单独刺激，或联合IL-21刺激的细胞，在48小时与72小时时的基因表达水平进行了分析。