It is well-known that the functioning of the immune system gradually deteriorates with age, and we are increasingly confronted with its consequences as the life expectancy of the human population increases. Changes in the T-cell pool are among the most prominent features of the changing immune system during healthy ageing, and changes in the naive T-cell pool in particular are generally held responsible for its gradual deterioration. These changes in the naive T-cell pool are thought to be due to involution of the thymus. It is commonly believed that the gradual loss of thymic output induces compensatory mechanisms to maintain the number of naive T cells at a relatively constant level, and induces a loss of diversity in the T-cell repertoire. Here we review the studies that support or challenge this widely-held view of immune ageing and discuss the implications for vaccination strategies.

众所周知，免疫系统的功能随着年龄的增长而逐渐恶化，随着人类预期寿命的延长，我们越来越面临其后果。T细胞库的变化是健康老龄化过程中免疫系统变化的最显着特征之一，尤其是幼稚T细胞库的变化通常被认为是其逐渐恶化的原因。幼稚 T 细胞库中的这些变化被认为是由于胸腺退化所致。人们普遍认为，胸腺输出的逐渐丧失会诱导补偿机制，将初始T细胞的数量维持在相对恒定的水平，并导致T细胞库多样性的丧失。在这里，我们回顾了支持或挑战这种广泛持有的免疫衰老观点的研究，并讨论了疫苗接种策略的影响。