TARGET CELL DAMAGE BY IMMUNE MECHANISMS

为了检验淋巴细胞的颗粒吐出模型 细胞毒性，我们检测了大鼠的细胞毒活性。 胃粘膜肥大细胞瘤细胞系RBL转导基因后的研究 细胞毒性淋巴细胞颗粒成分。我们已经分析了 三倍、双倍和单一RBL转染体的细胞毒活性 细胞溶素(Cy)和颗粒丝氨酸蛋白酶的表达克隆 颗粒酶A(GZA)和颗粒酶B(GZB)。有了红血球靶标， 颗粒酶的表达对较高的溶血力没有影响 所研究的所有RBL-Cy-x克隆的CTL。在肿瘤靶点上， RBL-Cy克隆仅表现出轻微的细胞毒性，没有伴随 以核破坏为目标。有四个不同的肿瘤靶点，都是溶解的 RBL-Cy-GZB和RBL-Cy-GZA-GZB克隆的效价和靶DNA损伤 与颗粒酶表达相关，与细胞溶血素表达无关。 Rbl-Cy-GZA-GZB克隆具有相近的裂解和解核活性 (裂解单位减少3倍-4倍)克隆的CTL。使用两种不同的肿瘤 靶细胞，溶核和溶细胞活性的比较 两个RBL-Cy-GZA RBL-Cy-GZB克隆和RBL-Cy-GZA-GZB克隆 揭示了后者比 双基因转染体的活性，表明两种颗粒酶 协同作用触发靶细胞死亡和核 崩溃了。看看核损害是否是必要的 颗粒酶介导的细胞死亡途径--去核释放~(51)Cr 将肿瘤靶细胞与完整的肿瘤细胞和红细胞进行比较。 去核的胞质靶细胞的行为与完整的肿瘤细胞相似。 而不是红细胞，因为RBL-Cy-GZA-GZB杀死它们的效果比 RBL-Cy.使用携带Fas的靶细胞也得到了类似的结果 和携带Fas配体的效应细胞系d11S。因此，我们得出结论 细胞核并不参与颗粒酶引发的 死亡途径还是在Fas触发的死亡途径中，这是两种 细胞毒性淋巴细胞触发的主要死亡途径。

In order to test the granule exocytosis model for lymphocyte cytotoxicity, we have examined the cytotoxic activity of the rat mucosal mast cell tumor line RBL after transfection with genes for cytotoxic lymphocyte granule components. We have analyzed the cytotoxic activity of triple, double, and single RBL transfectant clones expressing cytolysin (cy) and the granule serine proteases granzyme A (gza) and granzyme B (gzb). With red cell targets, granzyme expression has no effect on lytic potency, which is higher than cloned CTL for all RBL-cy-x clones studied. On tumor targets, RBL-cy clones show only modest cytotoxicity, with no accompanying target nuclear damage. With four different tumor targets, both lytic potency and target DNA damage of RBL-cy-gzb and RBL-cy-gza-gzb clones correlated with granzyme expression but not cytolysin expression. RBL-cy-gza-gzb clones show lytic and nucleolytic activities close (3x-4x fewer lytic units) to cloned CTL. Using two different tumor target cells, comparison of the nucleolytic and cytolytic activities of both RBL-cy-gza RBL-cy-gzb clones with RBL-cy-gza-gzb clones reveals that the latter are much more active than the sum of the activities of the double transfectants, showing that the two granzymes interact synergistically to trigger target cell death and nuclear breakdown. To see if the nuclear damage is required for the granzyme-mediated cell death pathway, 51Cr release from enucleated tumor target cells was compared to intact tumor cells and red cells. The enucleated cytoplast targets behaved like the intact tumor cells and not red cells, in that RBL-cy-gza-gzb killed them much better than RBL-cy. Similar results were obtained using Fas-bearing target cells and the Fas ligand-bearing effector cell line d11S. Thus we conclude that the nucleus is not involved in either the granzyme-triggered death pathway or in the Fas-triggered death pathway, which are the two principle death pathways triggered by cytotoxic lymphocytes.