Evolutionary Aspects of Infections: Inflammation and Sickness Behaviors
Evolutionary Aspects of Infections: Inflammation and Sickness Behaviors
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DOI：
10.1007/7854_2022_363
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发表时间：
2023-01-01
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影响因子：
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通讯作者：
Dantzer, Robert
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作者：
Dantzer, Robert
疾病行为最初被概念化为对传染性病原体的发烧反应的对应行为。它有助于将体温提高到较高的设定点并将其维持在这个新的水平，并且它还有一个额外的好处，那就是使虚弱的有机体能够保护自己免受其他危险。激活的免疫细胞产生的促炎细胞因子的行为效应的发现为这种现象提供了细胞和分子基础。对健康啮齿动物施用细胞因子或细胞因子诱导剂（如脂多糖）可以揭示炎症引起的疾病行为和发烧反应之间的异同。它还使我们了解了外周触发的炎症反应如何传播到大脑并诱发疾病的行为表现。在行为层面，疾病行为是一种动机状态的表达，这种动机状态会重组面对微生物病原体的感知和行动，就像面对捕食者的恐惧一样，乍一看似乎强化了这种行为的适应性价值。然而，疾病行为的所有方面并不总是对有机体有利。厌食症就是这种情况，在细菌感染的情况下有益，但在病毒感染的情况下有害。此外，对自然条件下疾病行为的研究表明，与任何其他防御行为一样，疾病行为需要在患病个体的生存利益和所产生的成本之间进行权衡，尤其是在群居环境中。由于这些研究，越来越多的证据表明，疾病行为的表现形式比最初想象的更加多变，这种变异性不仅取决于病原体和感染发生的社会背景，还取决于个体因素，包括物种、性别、年龄、营养和生理状态。
Sickness behavior was conceptualized initially as the behavioral counterpart of the fever response to infectious pathogens. It helps to raise body temperature to its higher setpoint and to maintain it at this new level and it has the additional benefit of enabling a weakened organism to protect itself from other dangers. The discovery of the behavioral effects of proinflammatory cytokines produced by activated immune cells provided a cellular and molecular basis to this phenomenon. The administration of cytokines or cytokine inducers like lipopolysaccharide to healthy rodents allowed to reveal the similarities and differences between inflammation-induced sickness behavior and the fever response. It also led to the understanding of how the inflammatory response that is triggered at the periphery can propagate into the brain and induce the behavioral manifestations of sickness. At the behavioral level, the demonstration that sickness behavior is the expression of a motivational state that reorganizes perception and action in face of a microbial pathogen just like fear in face of a predator appeared at first glance to strengthen the adaptive value of this behavior. However, all aspects of sickness behavior are not always favorable for the organism. This is the case for anorexia that is beneficial in the context of bacterial infection but detrimental in the context of viral infection. In addition, studies of sickness behavior in natural conditions revealed that like any other defensive behavior, sickness behavior requires trade-offs between its survival benefits for the sick individual and the costs incurred especially in the context of gregarious groups. Thanks to these studies, evidence is emerging that sickness behavior is much more variable in its expression than initially thought, and that part of this variability depends not only on the pathogen and the social context in which the infection develops but also on individual factors including species, sex, age, nutrition, and physiological status.