Liu Fei, Whitton J Lindsay
Department of Neuropharmacology, The Scripps Research Institute, La Jolla, CA 92037, USA.
J Immunol. 2005 May 15;174(10):5936-40. doi: 10.4049/jimmunol.174.10.5936.
Virus-specific CD8(+) T cells produce IFN-gamma after Ag contact and, in the absence of this cytokine, the host often cannot eradicate infection. However, our ability to identify cells that are actively expressing this critical effector function in vivo is limited, because the protein is rapidly secreted. In this study, we describe a simple approach that circumvents the need for ex vivo Ag stimulation and allows the enumeration of CD8(+) T cells that are actively synthesizing IFN-gamma in vivo during primary and secondary virus infections. The proportion of Ag-specific primary CD8(+) T cells producing IFN-gamma peaks at 5 days postinfection, when the T cell population is still expanding exponentially. In vivo IFN-gamma synthesis by memory cells is explosive, peaking at approximately 12 h after secondary infection and terminating hours thereafter. This technique will be useful when evaluating in vivo immune cell activity in many situations, including a variety of noninfectious (e.g., autoimmune) diseases.
病毒特异性CD8(+) T细胞在接触抗原后会产生γ干扰素，并且在缺乏这种细胞因子的情况下，宿主通常无法根除感染。然而，我们在体内识别正在积极表达这种关键效应功能的细胞的能力有限，因为该蛋白会迅速分泌。在本研究中，我们描述了一种简单的方法，该方法无需体外抗原刺激，并且能够对在初次和二次病毒感染期间体内正在积极合成γ干扰素的CD8(+) T细胞进行计数。产生γ干扰素的抗原特异性初始CD8(+) T细胞的比例在感染后5天达到峰值，此时T细胞群体仍在呈指数级扩增。记忆细胞在体内合成γ干扰素的过程具有爆发性，在二次感染后约12小时达到峰值，并在数小时后结束。当评估许多情况下的体内免疫细胞活性时，包括各种非感染性（如自身免疫性）疾病，这项技术将很有用。
