Herndler-Brandstetter Dietmar, Veel Ellen, Laschober Gerhard T, Pfister Gerald, Brunner Stefan, Walcher Susanne, Parson Walther, Lepperdinger Günter, Grubeck-Loebenstein Beatrix
Institute for Biomedical Aging Research, Austrian Academy of Sciences, A-6020 Innsbruck, Austria.
Biol Chem. 2008 May;389(5):561-8. doi: 10.1515/bc.2008.052.
The age-related decline in immune system functions is responsible for the increased prevalence of infectious diseases and the low efficacy of vaccination in elderly individuals. In particular, the number of peripheral naive T-cells declines throughout life and they exhibit severe functional defects at advanced age. However, we have recently identified a non-regulatory CD8+CD45RO+ CD25+ T-cell subset that occurs in a subgroup of healthy elderly individuals, who still exhibit an intact humoral immune response following influenza vaccination. Here, we demonstrate that CD8+CD45RO+CD25+ T-cells share phenotypic and functional characteristics with naive CD8+CD45RA+CD28+ T-cells from young individuals, despite their expression of CD45RO. CD8+CD45RO+ CD25+ T-cells also have long telomeres and upon antigenic challenge, they efficiently expand in vitro and differentiate into functional effector cells. The expanded population also maintains a diverse T-cell receptor repertoire. In conclusion, CD8+CD45RO+CD25+ T-cells from elderly individuals compensate for the loss of functional naive T-cells and may therefore be used as a marker of immunological competence in old age.
免疫系统功能随年龄增长而下降，这导致老年人传染病患病率增加以及疫苗接种效果不佳。特别是，外周幼稚T细胞数量在一生中都会减少，并且在老年时表现出严重的功能缺陷。然而，我们最近发现了一个非调节性CD8+CD45RO+CD25+T细胞亚群，该亚群出现在一部分健康老年人中，这些老年人在接种流感疫苗后仍表现出完整的体液免疫反应。在这里，我们证明CD8+CD45RO+CD25+T细胞与年轻个体的幼稚CD8+CD45RA+CD28+T细胞具有相同的表型和功能特征，尽管它们表达CD45RO。CD8+CD45RO+CD25+T细胞也有较长的端粒，在受到抗原刺激后，它们在体外能有效扩增并分化为功能性效应细胞。扩增后的群体也维持了多样化的T细胞受体库。总之，老年个体的CD8+CD45RO+CD25+T细胞弥补了功能性幼稚T细胞的损失，因此可能被用作老年免疫能力的标志物。
