LAK細胞の発現する膜結合型リンフォトキシンの癌細胞障害活性の解析

本研究旨在提高肿瘤过继免疫治疗的临床疗效。为此，从我们首次报道的LAK细胞膜相关淋巴毒素(MLT)的角度探讨了LAK细胞靶向杀伤肿瘤细胞的机制。为了尝试利用克隆细胞进行研究，进行了LAK细胞的克隆。目前已建立了多个LAK细胞克隆，但由于MLT在这些克隆上的表达水平较低，不能用于mLT的分析，因此本研究采用常规LAK细胞。利用传统的LAK细胞，出现了一些新的证据。除常规NK细胞外，LAK细胞对肿瘤细胞的杀伤活性和LAK细胞杀伤活性与MLT密切相关，但与可溶性分泌型LT无关。新型杀伤活性在用~(51)&GT；Cr建立的短期杀伤实验体系中表现明显，但在与LAK细胞分泌细胞因子相关的长期杀伤实验中不一定明显。MLT的作用是通过未知的受体实现的，但通过两个TNF受体，可溶性LT与这两个受体结合并发出信号。表达MLT的LAK细胞上调靶肿瘤细胞表面ICAM-1的表达，在LAK细胞杀伤靶肿瘤细胞中起重要作用。这种上调LAK细胞ICAM-1表达的作用不是MLT本身起作用的，而是LAK细胞上的一种统一的膜因子。这种作用不是由LAK细胞分泌的可溶性因子起作用的。MLT相关的ICAM-1上调LAK细胞膜因子的鉴定将为过继免疫治疗带来新的进展。

This research was aimed to improve clinical effects of adoptive immunotherapy of cancer. For this purpose, mechanisms underlying the target tumor cell killing of LAK cells were investigated from the point of membrance-associated lymphotoxin (mLT) expressred on LAK cells, which we originally reported. In an attempt trying to investigate using cloned cells, cloning of LAK cells were carried out. Several lines of LAK cell clones were established, however, the expression of mLT on all these clones were too low to use them in the analysis of mLT.Therefore, conventional LAK cells were employed in this research. Using conventional LAK cells, several novel evidences came out. Novel tumor cell killing activity of LAK cells other than conventional NK and LAK killing activity were indentified, which was closely related with mLT but not soluble secreted LT.The novel killing activity was evident in a short term killing assay system using ^<51>Cr but not necessarily evident on long term killing assay which was related with cytokine secreted by LAK cells. The effect of mLT was executed via unidentified receptor but via two TNF receptors, to which soluble LT binds and sends signals. LAK cells expressing mLT up-regulated ICAM-1 expression on target tumor cells, which plays important role in target tumor cell killing by LAK cells. This up-regulating effect on ICAM-1 expression by LAK cells was not exerted by mLT itself, but by an unidenntified membrane factor on LAK cells. This effect was not exerted by soluble factors secreted by LAK cells. The identification of the mLT-related ICAM-1 up-regulating membrane factor of LAK cells would bring out an improvement in adoptive immunotherapy.