Duerst R, Werberig K
Department of Pediatrics, University of Rochester Medical Center, New York 14642.
Cell Immunol. 1991 Sep;136(2):361-72. doi: 10.1016/0008-8749(91)90359-j.
Activation of macrophages (M phi) for host defense against tumor cells follows a sequence of priming events followed by an initiating stimulus that results in production and release of cytotoxic molecules that mediate target cell killing. We have developed a model to study specific macrophage cytotoxicity in vitro utilizing a cultured murine M phi cell line, J774. Specific cytotoxicity of cultured human gastrointestinal tumor cells is achieved in the presence of murine IgG2a monoclonal antibody (mAb) 17-1-A. The ability of these cells to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) is greatly enhanced following gamma-irradiation. ADCC can be demonstrated at mAb 17-1-A concentrations greater than or equal to 1 microgram/ml and effector/target cell ratios greater than or equal to 2. Exposure to doses greater than or equal to 10 Gy of gamma-irradiation increases ADCC threefold. Varying the duration from J774 M phi exposure to gamma-irradiation until addition of antibody-coated target cells showed that the primed state for ADCC is stable for at least 8 days but approximately 24 hr is required for complete development of the primed state. mAb-dependent target cell death begins 8 hr after addition of mAb and labeled target cells to primed effector cells and is complete by 24 hr. Incubation of unirradiated J774 M phi effector cells with recombinant murine interferon-gamma (rmIFN-gamma) also results in enhanced ADCC, but the extent of target cell killing achieved is less than that following priming by gamma-irradiation. Concomitant priming of gamma-irradiated J774 M phi with rmIFN-gamma increases the extent of ADCC. Further study of irradiated J774 cells may elucidate the molecular pathways utilized by M phi for achieving and maintaining the primed state for ADCC. Irradiated J774 cells will also provide a homogenous, stably primed cell type in which to examine the mechanism(s) of cytotoxicity employed by tumoricidal M phi.
巨噬细胞（M phi）被激活以抵御肿瘤细胞的宿主防御遵循一系列启动事件，随后是引发刺激，导致产生和释放介导靶细胞杀伤的细胞毒性分子。我们已经开发了一种模型，利用培养的小鼠M phi细胞系J774在体外研究特异性巨噬细胞细胞毒性。在小鼠IgG2a单克隆抗体（mAb）17-1-A存在的情况下，培养的人胃肠道肿瘤细胞可实现特异性细胞毒性。γ射线照射后，这些细胞介导抗体依赖性细胞介导的细胞毒性（ADCC）的能力大大增强。在mAb 17-1-A浓度大于或等于1微克/毫升且效应细胞/靶细胞比率大于或等于2时可证明ADCC。暴露于大于或等于10 Gy的γ射线剂量可使ADCC增加三倍。改变从J774 M phi暴露于γ射线照射到添加抗体包被的靶细胞的持续时间表明，ADCC的启动状态至少稳定8天，但完全形成启动状态大约需要24小时。mAb依赖性靶细胞死亡在将mAb和标记的靶细胞添加到启动的效应细胞后8小时开始，并在24小时内完成。未照射的J774 M phi效应细胞与重组小鼠干扰素-γ（rmIFN-γ）孵育也会导致ADCC增强，但实现的靶细胞杀伤程度低于γ射线照射引发后的程度。用rmIFN-γ同时启动γ射线照射的J774 M phi会增加ADCC的程度。对照射后的J774细胞的进一步研究可能会阐明M phi用于实现和维持ADCC启动状态所利用的分子途径。照射后的J774细胞还将提供一种同质、稳定启动的细胞类型，用于研究杀肿瘤M phi所采用的细胞毒性机制。
