Woodland David L, Blackman Marcia A
Trudeau Institute, Saranac Lake, NY 12983, USA.
Trends Immunol. 2006 Jul;27(7):303-7. doi: 10.1016/j.it.2006.05.002. Epub 2006 May 30.
Increasing age is associated with a decreasing ability to mediate effective immune responses to newly encountered antigens. It is generally believed that this reflects the age-associated decline in the number, repertoire and function of available naive T cells. Here, we propose that naive T cells become increasingly irrelevant to the immune system, and that responses to newly encountered antigens are progressively dominated by cross-reactive memory T cells as the individual ages. In addition, we propose that the majority, if not all, of the response to newly encountered antigens in the elderly is mediated by cross-reactive memory T cells. This predicts highly stochastic responses to new infections that should vary between individuals, and has important implications for vaccination strategies in the elderly.
年龄增长与介导针对新遇到抗原的有效免疫反应的能力下降有关。人们普遍认为，这反映了与年龄相关的可用初始T细胞数量、库和功能的下降。在此，我们提出初始T细胞对免疫系统的相关性日益降低，并且随着个体年龄增长，对新遇到抗原的反应逐渐由交叉反应性记忆T细胞主导。此外，我们提出老年人对新遇到抗原的反应，即使不是全部，大部分也是由交叉反应性记忆T细胞介导的。这预示着对新感染的反应具有高度随机性，因人而异，并且对老年人的疫苗接种策略具有重要意义。
