Gagnon L, Girard M, Sullivan A K, Rola-Pleszczynski M
Department of Pediatrics, Faculty of Medicine, University of Sherbrooke, QC, Canada.
Cell Immunol. 1987 Dec;110(2):243-52. doi: 10.1016/0008-8749(87)90120-1.
The addition of leukotriene B4 (LTB4) to cytotoxicity assays measuring natural killer (NK) or natural cytotoxic (NC) cell activities resulted in significantly augmented killing of K562 or herpes simplex virus (HSV)-infected target cells, respectively. Since the mechanism of cytotoxicity implies several steps, including the binding of effectors to targets which is Mg2+-dependent and the programming of lysis of the target which is Ca2+-dependent, we undertook to define the step(s) at which LTB4 acted in augmenting cytotoxicity. Our results showed that LTB4 significantly increased the percentage of effector-target conjugates when K562- or HSV-infected targets were incubated with lymphocytes. Maximal binding occurred at a concentration of LTB4 of 1 X 10(-10) M. Preincubation of lymphocytes and not target cells with LTB4 was sufficient to observe the increased binding. PBML binding to and killing of the NK-resistant target clone I, derived from K562, was not enhanced by LTB4. In the absence of Ca2+, cytotoxicity was impaired and LTB4 could not restore it. Use of a single cell lytic assay demonstrated augmented efficiency of lysis of both K562 and HSV-infected targets in the presence of LTB4. These findings suggest that LTB4 may augment natural cytotoxicity by enhancing target cell recognition by cytotoxic effector cells and subsequently by augmenting their lytic efficiency.
在测量自然杀伤（NK）细胞或自然细胞毒性（NC）细胞活性的细胞毒性试验中添加白三烯B4（LTB4），分别导致对K562或单纯疱疹病毒（HSV）感染的靶细胞的杀伤显著增强。由于细胞毒性机制涉及几个步骤，包括效应细胞与靶细胞的结合（这是Mg2+依赖性的）以及靶细胞裂解的编程（这是Ca2+依赖性的），我们着手确定LTB4在增强细胞毒性过程中起作用的步骤。我们的结果表明，当K562或HSV感染的靶细胞与淋巴细胞孵育时，LTB4显著增加了效应细胞 - 靶细胞结合物的百分比。最大结合发生在LTB4浓度为1×10（-10）M时。用LTB4预孵育淋巴细胞而非靶细胞足以观察到结合增加。LTB4并未增强源自K562的NK抗性靶细胞克隆I与PBML的结合及杀伤作用。在没有Ca2+的情况下，细胞毒性受损，LTB4无法恢复它。使用单细胞裂解试验表明，在存在LTB4的情况下，K562和HSV感染的靶细胞的裂解效率均有所提高。这些发现表明，LTB4可能通过增强细胞毒性效应细胞对靶细胞的识别并随后提高其裂解效率来增强自然细胞毒性。
