Microbial infection poses a threat to organismal homeostasis and therefore must be efficiently counteracted by host defense mechanisms. It has been recently demonstrated that the immune system may anticipate an emerging pathogenic exposure through a heightened inflammatory state. Such anticipatory responses to fluctuating environmental conditions are typically orchestrated by the circadian clock, an intrinsic time-keeping system that adapts tissue physiology to diurnal variations in external influences. Here, we review current knowledge about the interplay between the circadian clock and antimicrobial responses. We summarize the molecular strategies employed by the circadian system against specific pathogens, the core-clock proteins as well as cells in which they are expressed that mediate host defense, and the consequences of circadian variations on immune function. Furthermore, we highlight the possible implications of such circadian gating in immune reactions against pathogenic infections for the chronopharmacology of antibacterial and antiviral therapies.

微生物感染对生物体内平衡构成威胁，因此必须通过宿主防御机制有效地加以抵抗。最近已经证明，免疫系统可以通过增强的炎症状态预期出现新的病原体暴露。这种对变化的环境条件的预期响应通常由生物钟来安排，生物钟是一种固有的计时系统，可使组织生理适应外界影响的昼夜变化。在这里，我们回顾了有关生物钟和抗菌反应之间相互作用的当前知识。我们总结了昼夜节律系统针对特定病原体，核心时钟蛋白以及表达它们介导宿主防御的细胞所采用的分子策略，以及昼夜节律变化对免疫功能的影响。此外，我们强调了这种昼夜节律门控在针对致病菌感染的免疫反应中对抗菌和抗病毒疗法的时间药理作用的可能意义。