The immune system in the elderly III. Innate immunity
The immune system in the elderly III. Innate immunity
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DOI：
10.1007/bf02786468
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发表时间：
1999-01-01
影响因子：
4.4
通讯作者：
Quaglino, D
中科院分区：
文献类型：
--
作者：
Ginaldi, L;De Martinis, M;Quaglino, D
科普感染因子和癌细胞的能力不仅存在于由克隆分布的T和B淋巴细胞介导的针对特异性抗原的适应性免疫应答中，而且存在于天然免疫应答中。这些先天防御机制包括趋化性、吞噬作用、天然细胞毒性、细胞相互作用和可溶性介质或细胞因子。然而，特异性和天然免疫机制总是紧密联系和相互关联的，提供了对病原体的主要防御。作者讨论了随着年龄的增长，在粒细胞和自然杀伤（NK）细胞活性，粘附分子的表达和功能，以及细胞因子的产生模式中观察到的主要变化。由于吞噬功能是免疫系统消除大多数细胞外致病微生物的主要机制，因此分析该功能具有临床重要性。老年受试者的中性粒细胞通常表现出吞噬能力减弱，以及呼吸爆发抑制，尽管处于激活状态。NK细胞在衰老过程中的活性已被广泛研究，并报道了不同的结果。最一致的数据表明，随着年龄的增长，具有高NK活性的细胞增加。来自健康百岁老人的细胞可以有效地杀死靶细胞。这一发现似乎表明，先天免疫，特别是NK细胞活性，并没有随着年龄的增长而严重恶化。相反，低NK活性是即将发病的预测因子。免疫衰老与几种细胞粘附分子（CAM）的表达增加有关，导致粘附能力增强。最后，负责淋巴细胞分化、增殖和存活的细胞因子网络也随着年龄经历复杂的变化。主要发现是Th1细胞因子向Th2细胞因子的转变和促炎细胞因子的增加，这可以解释与年龄相关的病理事件的许多方面，如动脉粥样硬化和骨质疏松症。
The capability to cope with infectious agents and cancer cells resides not only in adaptive immune responses against specific antigens, mediated by T and B lymphocytes clonally distributed, but also in natural immune reactions. These innate defence mechanisms include chemotaxis, phagocytosis, natural cytotoxicity, cell interactions, and soluble mediators or cytokines. However, specific and natural immune mechanisms are always closely linked and interconnected, providing the primary defense against pathogens. The Authors discuss the main changes observed with advancing age in granulocytes and natural killer (NK) cell activity, in the expression and function of adhesion molecules, and in the pattern of cytokine production. Since phagocytic function is the primary mechanism through which the immune system eliminates most extracellular pathogenic microrganisms, analysis of this function is of clinical importance. Neutrophils from aged subjects often exhibit a diminished phagocytic capacity, as well as a depressed respiratory burst, notwithstanding an activated state. The activity of NK cells during aging has been studied extensively and different results have been reported. The most consistent data indicate an increase in cells with high NK activity with advancing age. Cells from healthy centenarians can efficiently kill target cells. This finding seems to suggest that innate immunity and in particualr NK cell activity, is not heavily deteriorated with age. Conversely, a low NK activity is a predictor of impending morbidity. Immunosenescence is associated with increased expression of several cell adhesion molecules (CAM) resulting in an augmented capacity to adhere. Finally, also the cytokine network, responsible for differentiation, proliferation, and survival of lymphoid cells, undergoes complex changes with age. The main findings are a Th1 to Th2 cytokine production shift and an increased production of proinflammatory cytokines, which could explain many aspects of age-associated pathological events, such as atherosclerosis and osteoporosis.