Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, United States of America.
Nutritional Immunology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, United States of America.
Prog Neuropsychopharmacol Biol Psychiatry. 2022 Aug 30;118:110576. doi: 10.1016/j.pnpbp.2022.110576. Epub 2022 May 17.
Immunosenescence is a term used to describe the age-related changes in the immune system. Immunosenescence is associated with complex alterations and dysregulation of immune function and inflammatory processes. Age-related changes in innate immune responses including alterations in chemotactic, phagocytic, and natural killing functions, impaired antigen presenting capacity, and dysregulated inflammatory response have been described. The most striking and best characterized feature of immunosenescence is the decline in both number and function of T cells. With age there is decreased proliferation, decreased number of antigen-naïve T cells, and increased number of antigen-experienced memory T cells. This decline in naïve T cell population is associated with impaired immunity and reduced response to new or mutated pathogens. While the absolute number of peripheral B cells appears constant with age, changes in B cell functions including reduced antibody production and response and cell memory have been described. However, the main alteration in cell-mediated function that has been reported across all species with aging is those observed in in T cell. These T cell mediated changes have been shown to contribute to increased susceptibility to infection and cancer in older adults. In addition to functional and phenotype alterations in immune cells, studies demonstrate that circulating concentrations of inflammatory mediators in older adults are higher than those of young. This low grade, chronic inflammatory state that occurs in the context of aging has been termed "inflammaging". This review will focus on age-related changes in the immune system including immunosenescence and inflammation as well as the functional consequences of these age-related alterations for the aged.
免疫衰老（Immunosenescence）是一个用来描述免疫系统随年龄变化的术语。免疫衰老与免疫功能和炎症过程的复杂改变和失调有关。已经描述了先天免疫反应随年龄的变化，包括趋化、吞噬和自然杀伤功能的改变、抗原呈递能力受损以及炎症反应失调。免疫衰老最显著和最具特征的特征是 T 细胞数量和功能的下降。随着年龄的增长，增殖减少，抗原-naive T 细胞数量减少，抗原经验记忆 T 细胞数量增加。这种幼稚 T 细胞群体的减少与免疫受损和对新的或突变的病原体的反应减少有关。虽然外周 B 细胞的绝对数量随年龄保持不变，但已经描述了 B 细胞功能的变化，包括抗体产生和反应以及细胞记忆的减少。然而，随着衰老，所有物种中报告的细胞介导功能的主要改变是在 T 细胞中观察到的改变。这些 T 细胞介导的变化已被证明导致老年人易感染和癌症。除了免疫细胞的功能和表型改变外，研究还表明，老年人循环中炎症介质的浓度高于年轻人。这种在衰老背景下发生的低度、慢性炎症状态被称为“炎症衰老”。这篇综述将重点介绍免疫系统随年龄的变化，包括免疫衰老和炎症，以及这些与年龄相关的改变对老年人的功能后果。
