Facchini A, Mariani E, Mariani A R, Papa S, Vitale M, Manzoli F A
Instituti di Clinica Medica, Universita' di Bologna, Italy.
Clin Exp Immunol. 1987 May;68(2):340-7.
The phenotype and functional activity of circulating T and natural killer (NK) cells was investigated in a group of selected normal elderly donors in comparison with a group of normal young individuals. Old subjects exhibit a decline in circulating T cells and an impaired response to mitogens (Con A, PHA) associated with a relative increase in cells reacting with Leu 7 and Leu 11a monoclonal antibodies, directed against large granular lymphocytes with NK activity. The rise in circulating NK cells observed in the elderly was not associated with a concomitant increase in NK cytolytic activity against K 562 tumour cells, and time course kinetics of the cytotoxic reaction was similar to that observed in young subjects. When a greater than 95% pure population of Leu 11a+ cells from old individuals was sorted by flow cytometry and their functional cytotoxic activity examined, a significant decrease in NK cytotoxicity was detected. The target cell binding capacity of effector cells, morphologically evaluated at single cell level, did not differ in old and young subjects, even though bound cells from young donors have a higher lytic capacity. These data show that an increase in circulating NK granular lymphocytes occurs during human ageing, but suggest that in old subjects only a subset of NK cells is active in order to maintain a functional response similar to that observed in the young.
与一组正常年轻个体相比，对一组选定的正常老年供体的循环T细胞和自然杀伤（NK）细胞的表型和功能活性进行了研究。老年受试者的循环T细胞数量减少，对丝裂原（刀豆蛋白A、植物血凝素）的反应受损，同时与针对具有NK活性的大颗粒淋巴细胞的Leu 7和Leu 11a单克隆抗体反应的细胞相对增加。在老年人中观察到的循环NK细胞增加与对K 562肿瘤细胞的NK细胞溶解活性的相应增加无关，并且细胞毒性反应的时间进程动力学与在年轻受试者中观察到的相似。当通过流式细胞术对来自老年个体的纯度大于95%的Leu 11a+细胞群体进行分选并检测其功能细胞毒性活性时，检测到NK细胞毒性显著降低。即使来自年轻供体的结合细胞具有更高的裂解能力，但在单细胞水平上形态学评估的效应细胞的靶细胞结合能力在老年和年轻受试者中并无差异。这些数据表明，在人类衰老过程中循环NK颗粒淋巴细胞会增加，但表明在老年受试者中只有一部分NK细胞具有活性，以维持与年轻受试者中观察到的相似的功能反应。
