Harris D T, Kozumbo W J, Cerutti P, Cerottini J C
J Immunol. 1987 Jan 15;138(2):600-5.
It is well-established that activated T cells proliferate in response to interleukin 2 (IL 2) and produce various soluble lymphokines such as macrophage-activating factor (MAF) in response to antigen. Prior to investigating the molecular events involved in signaling the initiation of these responses in cloned murine cytotoxic T lymphocytes (CTL), we determined whether these responses could occur independently, and we established for each response the time during which signal transducing mechanisms may function. It was found that this cloned CTL population was in a resting state (G1 phase of cell cycle) 7 days after stimulation with antigen plus IL 2. At this time, the incubation of these resting CTL with IL 2 for 4 to 6 hr resulted in a maximal proliferative response that was not accompanied by the production of MAF. Conversely, the incubation of resting CTL with antigen or lectin (in the absence of IL 2) for at least 8 hr resulted in the maximal production of MAF at 24 hr without inducing a proliferative response. In addition, antigen or lectin, but not IL 2, triggered an immediate (less than 1 min) and sustained (at least 8 hr) mobilization of intracellular calcium. The kinetics of this calcium response paralleled the minimum time (8 hr) that was required for resting CTL to interact with either antigen or lectin in order to produce maximal titers of MAF. These results indicate that proliferation and lymphokine (MAF) production in cloned murine CTL are independent events. In these resting CTL, the signal mechanisms that mediate the production of lymphokines are most likely restricted to the initial 8 hr of stimulation by antigen or lectin and involve the rapid and prolonged mobilization of cytoplasmic calcium. Proliferative signals, however, are probably complete within 4 to 6 hr after stimulation by IL 2 and do not involve readily demonstrable fluxes of cytoplasmic calcium, as determined by the fluorescent calcium probe Quin 2.
众所周知，活化的T细胞会对白介素2（IL-2）产生增殖反应，并在接触抗原时产生各种可溶性淋巴因子，如巨噬细胞活化因子（MAF）。在研究克隆的小鼠细胞毒性T淋巴细胞（CTL）中引发这些反应起始信号的分子事件之前，我们先确定了这些反应是否能独立发生，并为每种反应确定了信号转导机制可能起作用的时间。结果发现，在用抗原加IL-2刺激7天后，这群克隆的CTL处于静止状态（细胞周期的G1期）。此时，将这些静止的CTL与IL-2孵育4至6小时会产生最大增殖反应，且不伴有MAF的产生。相反，将静止的CTL与抗原或凝集素（无IL-2）孵育至少8小时，会在24小时时产生最大量的MAF，而不会诱导增殖反应。此外，抗原或凝集素而非IL-2能引发细胞内钙的立即（不到1分钟）且持续（至少8小时）动员。这种钙反应的动力学与静止CTL与抗原或凝集素相互作用以产生最大滴度MAF所需的最短时间（8小时）平行。这些结果表明，克隆的小鼠CTL中的增殖和淋巴因子（MAF）产生是独立事件。在这些静止的CTL中，介导淋巴因子产生的信号机制很可能仅限于抗原或凝集素刺激的最初8小时，并涉及细胞质钙的快速和持续动员。然而，增殖信号可能在IL-2刺激后4至6小时内完成，且如荧光钙探针Quin 2所测定的，不涉及明显的细胞质钙通量。
