Horvath J A, Mostowski H S, Okumura K, Bloom E T
Laboratory of Cellular Immunology, Food and Drug Administration, Bethesda, MD 20892.
Eur J Immunol. 1992 Oct;22(10):2649-54. doi: 10.1002/eji.1830221026.
The senescent decline of cytolytic T lymphocyte (CTL) activity was examined (a) to learn more about the effect of aging on the immune system, and (b) to probe the mechanism of cell-mediated cytolysis. The effect of age on the generation of pore-forming protein (Pfp) was examined at the cellular level in a murine model using CTL stimulated in allogeneic mixed lymphocyte culture (MLC). Pfp expression was analyzed by immunocytochemistry and enzyme-linked immunosorbent assay (ELISA). Immunocytochemical analyses of Pfp in MLC-stimulated splenic T cells from a large number of mice revealed that although stimulated cells from aged mice exhibited fewer Pfp-producing cells than those from young, the diminution in the proportion of Pfp+ cells was small compared to the age-related decrease in lytic activities (approximately 2-fold vs. approximately 7.4-fold, respectively). Time-course analysis disclosed similar kinetics for the generation of Pfp+ cells among responding cells from young and aged mice. No significant age-related difference in the proportion of Pfp+ cells was observed in MLC-stimulated lymph node cells despite a large and significant difference in lytic activity (approximately 6.5-fold). Purified CD8+ T cells demonstrated a large age-related difference in CTL activity (approximately 3-11-fold) and accounted for virtually all the Pfp. Although little difference in the proportion of Pfp+ CD8+ T cells could be detected between age groups, stimulated CD8+ cells or whole splenic T cells from old mice consistently exhibited a striking reduction in both the intensity of Pfp staining and the apparent numbers of granules per cell. This difference in Pfp was examined by ELISA and total Pfp levels were found to be approximately 12-fold greater in CTL generated from splenic T cells of young compared to aged mice. The results demonstrate that Pfp levels are reduced in CTL from aged compared to young mice at the level of the individual cells and suggest the possibility that a threshold level of Pfp may be required for potency of effector cell function.
研究了细胞毒性T淋巴细胞（CTL）活性的衰老性下降，（a）以更多地了解衰老对免疫系统的影响，（b）探究细胞介导的细胞溶解机制。在小鼠模型中，利用同种异体混合淋巴细胞培养（MLC）刺激的CTL，在细胞水平上研究了年龄对成孔蛋白（Pfp）生成的影响。通过免疫细胞化学和酶联免疫吸附测定（ELISA）分析Pfp表达。对大量小鼠MLC刺激的脾T细胞中Pfp进行免疫细胞化学分析发现，尽管老年小鼠的刺激细胞产生Pfp的细胞比年轻小鼠少，但与溶细胞活性的年龄相关下降相比，Pfp+细胞比例的减少较小（分别约为2倍和约7.4倍）。时间进程分析显示，年轻和老年小鼠反应细胞中Pfp+细胞的生成动力学相似。尽管溶细胞活性存在巨大且显著的差异（约6.5倍），但在MLC刺激的淋巴结细胞中未观察到Pfp+细胞比例的显著年龄相关差异。纯化的CD8+T细胞在CTL活性方面表现出较大的年龄相关差异（约3 - 11倍），并且几乎占所有Pfp。尽管不同年龄组之间检测到的Pfp+CD8+T细胞比例差异不大，但老年小鼠的刺激CD8+细胞或整个脾T细胞在Pfp染色强度和每个细胞的颗粒表观数量上均持续显著降低。通过ELISA检测了这种Pfp差异，发现与老年小鼠相比，年轻小鼠脾T细胞产生的CTL中总Pfp水平大约高12倍。结果表明，与年轻小鼠相比，老年小鼠CTL中单个细胞水平的Pfp水平降低，这表明效应细胞功能的效力可能需要Pfp的阈值水平。
