Department of Chemical Engineering, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Proc Natl Acad Sci U S A. 2012 Jan 31;109(5):1607-12. doi: 10.1073/pnas.1117194109. Epub 2011 Dec 12.
The release of cytokines by T cells defines a significant part of their functional activity in vivo, and their ability to produce multiple cytokines has been associated with beneficial immune responses. To date, time-integrated end-point measurements have obscured whether these polyfunctional states arise from the simultaneous or successive release of cytokines. Here, we used serial, time-dependent, single-cell analysis of primary human T cells to resolve the temporal dynamics of cytokine secretion from individual cells after activation ex vivo. We show that multifunctional, Th1-skewed cytokine responses (IFN-γ, IL-2, TNFα) are initiated asynchronously, but the ensuing dynamic trajectories of these responses evolve programmatically in a sequential manner. That is, cells predominantly release one of these cytokines at a time rather than maintain active secretion of multiple cytokines simultaneously. Furthermore, these dynamic trajectories are strongly associated with the various states of cell differentiation suggesting that transient programmatic activities of many individual T cells contribute to sustained, population-level responses. The trajectories of responses by single cells may also provide unique, time-dependent signatures for immune monitoring that are less compromised by the timing and duration of integrated measures.
T 细胞释放细胞因子定义了它们在体内功能活动的重要部分，它们产生多种细胞因子的能力与有益的免疫反应有关。迄今为止，时间积分的终点测量掩盖了这些多功能状态是来自细胞因子的同时释放还是连续释放。在这里，我们使用原代人 T 细胞的连续、时变、单细胞分析，在体外激活后解析单个细胞中细胞因子分泌的时间动态。我们表明，多功能、Th1 偏向的细胞因子反应（IFN-γ、IL-2、TNFα）是异步启动的，但是这些反应的后续动态轨迹以顺序方式有计划地演变。也就是说，细胞一次主要释放其中一种细胞因子，而不是同时保持多种细胞因子的活跃分泌。此外，这些动态轨迹与细胞分化的各种状态密切相关，这表明许多单个 T 细胞的短暂程序性活动有助于持续的群体水平反应。单细胞反应的轨迹也可能为免疫监测提供独特的、时变的特征，这些特征受综合测量的时间和持续时间的影响较小。
