The microbiome plays a fundamental role in the maturation, function, and regulation of the host-immune system from birth to old age. In return, the immune system has co-evolved a mutualistic relationship with trillions of beneficial microbes residing our bodies while mounting efficient responses to fight invading pathogens. As we age, both the immune system and the gut microbiome undergo significant changes in composition and function that correlate with increased susceptibility to infectious diseases and reduced vaccination responses. Emerging studies suggest that targeting age-related dysbiosis can improve health- and lifespan, in part through reducing systemic low-grade inflammation and immunosenescence—two hallmarks of the aging process. However—a cause and effect relationship of age-related dysbiosis and associated functional declines in immune cell functioning have yet to be demonstrated in clinical settings. This review aims to (i) give an overview on hallmarks of the aging immune system and gut microbiome, (ii) discuss the impact of age-related changes in the gut commensal community structure (introduced as microb-aging) on host-immune fitness and health, and (iii) summarize prebiotic- and probiotic clinical intervention trials aiming to reinforce age-related declines in immune cell functioning through microbiome modulation or rejuvenation.

从出生到老年，微生物组在宿主免疫系统的成熟、功能和调节中起着基础性作用。作为回报，免疫系统与我们体内数以万亿计的有益微生物共同进化出一种互惠关系，同时对入侵的病原体做出有效反应。随着年龄的增长，免疫系统和肠道微生物组的组成和功能都会发生显着变化，这与对传染病的易感性增加和疫苗接种反应降低有关。新兴研究表明，针对与年龄相关的生态失调可以改善健康和寿命，部分是通过减少全身低度炎症和免疫衰老——衰老过程的两个标志。然而，与年龄相关的生态失调与相关的免疫细胞功能下降之间的因果关系尚未在临床环境中得到证实。本综述旨在 (i) 概述衰老免疫系统和肠道微生物组的特征，(ii) 讨论与年龄相关的肠道共生群落结构变化（称为微生物衰老）对宿主免疫适应性的影响和健康，以及 (iii) 总结益生元和益生菌临床干预试验，旨在通过微生物组调节或恢复活力来加强与年龄相关的免疫细胞功能下降。