Aikoh T, Tomokuni A, Matsukii T, Hyodoh F, Ueki H, Otsuki T, Ueki A
Department of Hygiene, Kawasaki Medical School, Kurashiki 701-01, Japan.
Int J Oncol. 1998 Jun;12(6):1355-9. doi: 10.3892/ijo.12.6.1355.
Silica and related substances such as silicate have been proven to possess "adjuvant effects". We have previously reported a finding of polyclonal human T cell activation induced by silicate as a superantigen in vitro. In this study, we observed activation-induced cell death in human lymphocytes after stimulation with chrysotile, a kind of silicate. Apoptotic cells were detected flow cytometrically using the TUNEL assay, and the maximum appearance of TUNEL positive cells occurred on day 4 of incubation. Simultaneously the manifestation of small-sized cells in the specimens increased implying apoptosis. Fas expression on lymphocytes increased to day 3 of incubation with chrysotile, and then spontaneously decreased on day 4 when remarkable apoptosis could be detected. Based on these results it is conceivable that activation-induced cell death occurred through Fas-Fas ligand interaction in lymphocytes after stimulation with silicate in a concentration with which no acute cytotoxicity has been detected. Whether and how the repeated apoptosis in definite clones of lymphocytes causes the induction of sFas synthesis need clarification.
二氧化硅及相关物质（如硅酸盐）已被证明具有“佐剂效应”。我们之前曾报道过一项发现，即硅酸盐作为一种超抗原可在体外诱导人多克隆T细胞活化。在本研究中，我们观察到用一种硅酸盐——温石棉刺激后人淋巴细胞中活化诱导的细胞死亡。使用TUNEL法通过流式细胞术检测凋亡细胞，TUNEL阳性细胞的最大出现时间为孵育第4天。同时，标本中小细胞的表现增加，提示凋亡。淋巴细胞上Fas的表达在与温石棉孵育至第3天时增加，然后在第4天可检测到明显凋亡时自发下降。基于这些结果，可以推测在未检测到急性细胞毒性的浓度下，硅酸盐刺激后淋巴细胞中通过Fas - Fas配体相互作用发生了活化诱导的细胞死亡。淋巴细胞特定克隆中的反复凋亡是否以及如何导致sFas合成的诱导尚需阐明。
