人外周血CD8+T细胞CD28、CD56及CD57表达水平的老年性改变

目的:通过对健康老年人与青年人外周血CD8⁺T细胞CD28、CD56及CD57表达水平的比较性研究,探讨免疫衰老的细胞学机制。方法:采用三色免疫荧光标记流式细胞术分析青年组(20-35岁)与老年组(60-75岁)外周血CD8⁺CD28⁺、CD8⁺CD56⁺及CD8⁺CD57⁺T细胞水平。结果:老年组外周血CD8⁺CD28⁺T细胞明显低于青年组,阳性百分率分别为34.07±5.29和49.84±7.43(P＜0.05);而老年组CD8⁺CD56⁺T细胞及CD8⁺CD57⁺T细胞均明显高于青年组,前者阳性百分率分别为6.60±2.40和2.10±0.35,后者阳性百分率分别为41.82±6.01和22.89±2.80(P＜0.05)。结论:老年人CD8⁺T细胞CD28、CD56及CD57的表达率均随年龄增长有明显改变;CD28表达下降可能是引起免疫系统功能降低的重要原因,而CD56、CD57表达水平的增加则可能是机体对细胞免疫功能下降的一种代偿性适应。

Changes of CD28, CD56 and CD57 expression on CD8+T cells in the peripheral blood of healthy elderly individuals

AIM:The expression of CD28, CD56 and CD57 on CD8⁺T cells in the peripheral blood of young (age range 20-35) and elderly(age range 60-75) healthy donors were compared to explore the change of the cellular immune function with aging.METHODS:Three-color fluorescent flow cytometry was performed to analyze the differences in percentage of CD8⁺CD28⁺, CD8⁺CD56⁺ and CD8⁺CD57⁺T cells in the peripheral blood between the young and elderly groups.RESULTS:CD8⁺CD28⁺T cells in the peripheral blood of the elderly group was significantly lower than those in the young group, with percentage of 34.07±5.28 and 49.84±7.43,respectively (P＜0.05). Conversely, CD8⁺CD56⁺T cells and CD8⁺CD57⁺T cells in the peripheral blood of the elderly group were significantly higher than those in the young group, and the percentage was 6.60±2.40 vs 2.10±0.35,41.82±6.01 vs 22.89±2.80, respectively(P＜0.05).CONCLUSION:The expression of CD28, CD56 and CD57 on the CD8⁺T cells in the peripheral blood are changed significantly with aging. The decrease in CD28 expression may play an important role in the immunosenescence, while the increase in CD56 and CD57 expression seems to be a compensatory adaptation for the immune dysfunction.