Blanchard D K, McMillen S, Djeu J Y
University of South Florida College of Medicine, Department of Medical Microbiology and Immunology, Tampa 33612.
J Immunol. 1991 Oct 15;147(8):2579-85.
In an effort to determine the mechanism by which autologous monocytes are killed by lymphokine-activated killer cells, soluble mediators were examined for their direct effect on target cells. Extracellular ATP (ATPo), but not ADP, was found to lyse human culture-derived macrophages in a 6-h 51Cr-release assay. Treatment of monocytes with human rIFN-gamma rendered those cells significantly more sensitive to ATPo compared to untreated or granulocyte-macrophage CSF-(GM-CSF) treated cells. In addition, IFN-gamma-treated macrophages released approximately 80% of 51Cr label within 15 min after the addition of ATPo, whereas GM-CSF-treated cells did not release significant levels of radiolabel until 4 to 6 h after initial stimulation with ATPo. Time course studies also demonstrated that 3 days of incubation of macrophages with IFN-gamma induced optimal sensitivity to ATPo, although some effect was noted after 4 h of incubation. Thus, IFN-gamma treatment of macrophages elicited increased sensitivity to ATPo-mediated lysis, a phenomenon characterized by rapid release of 51Cr from labeled cells and which is possibly due to induction or activation of surface ATP-binding receptors different from those present on GM-CSF-treated or untreated macrophages.
为了确定淋巴因子激活的杀伤细胞杀死自体单核细胞的机制，研究了可溶性介质对靶细胞的直接作用。在一项6小时的51Cr释放试验中，发现细胞外ATP（ATPo）而非ADP能裂解人培养来源的巨噬细胞。与未处理或粒细胞-巨噬细胞集落刺激因子（GM-CSF）处理的细胞相比，用人重组干扰素-γ（rIFN-γ）处理单核细胞使这些细胞对ATPo的敏感性显著增加。此外，添加ATPo后15分钟内，经IFN-γ处理的巨噬细胞释放了约80%的51Cr标记物，而经GM-CSF处理的细胞直到用ATPo初次刺激后4至6小时才释放出显著水平的放射性标记物。时间进程研究还表明，巨噬细胞与IFN-γ孵育3天可诱导对ATPo的最佳敏感性，尽管孵育4小时后也观察到了一些效应。因此，IFN-γ处理巨噬细胞可提高其对ATPo介导的裂解的敏感性，这一现象的特征是标记细胞快速释放51Cr，可能是由于诱导或激活了与GM-CSF处理或未处理的巨噬细胞上不同的表面ATP结合受体。
