Bulut Ozlem, Kilic Gizem, Domínguez-Andrés Jorge, Netea Mihai G
Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, GA Nijmegen, The Netherlands.
Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, GA Nijmegen, The Netherlands.
Int Immunol. 2020 Nov 23;32(12):741-753. doi: 10.1093/intimm/dxaa052.
People with advanced age have a higher susceptibility to infections and exhibit increased mortality and morbidity as the ability of the immune system to combat infections decreases with age. While innate immune cells display functional defects such as decreased phagocytosis, chemotaxis and cytokine production, adaptive immune cells exhibit reduced receptor diversity, defective antibody production and a sharp decline in naive cell populations. Successful responses to vaccination in the elderly are critical to prevent common infections such as influenza and pneumonia, but vaccine efficacy decreases in older individuals compared with young adults. Trained immunity is a newly emerging concept that showed that innate immune cells possess non-specific immunological memory established through epigenetic and metabolic reprogramming upon encountering certain pathogenic stimuli. Clinical studies suggest that trained immunity can be utilized to enhance immune responses against infections and improve the efficiency of vaccinations in adults; however, how trained immunity responses are shaped with advanced age is still an open question. In this review, we provide an overview of the age-related changes in the immune system with a focus on innate immunity, discuss current vaccination strategies for the elderly, present the concept of trained immunity and propose it as a novel approach to enhance responses against infections and vaccinations in the elderly population.
老年人对感染的易感性更高，并且随着免疫系统对抗感染的能力随年龄增长而下降，其死亡率和发病率也会增加。虽然先天免疫细胞表现出功能缺陷，如吞噬作用、趋化性和细胞因子产生减少，但适应性免疫细胞表现出受体多样性降低、抗体产生缺陷以及幼稚细胞群体急剧下降。老年人对疫苗接种的成功反应对于预防流感和肺炎等常见感染至关重要，但与年轻人相比，老年人的疫苗效力会降低。训练有素的免疫是一个新出现的概念，它表明先天免疫细胞具有通过在遇到某些致病刺激时进行表观遗传和代谢重编程而建立的非特异性免疫记忆。临床研究表明，训练有素的免疫可用于增强针对感染的免疫反应并提高成人疫苗接种的效率；然而，训练有素的免疫反应如何随年龄增长而形成仍是一个悬而未决的问题。在这篇综述中，我们概述了免疫系统中与年龄相关的变化，重点是先天免疫，讨论了当前针对老年人的疫苗接种策略，介绍了训练有素的免疫概念，并提出将其作为一种增强老年人群体对感染和疫苗接种反应的新方法。
