To survive in a world dominated by bacteria, eukaryotes have evolved numerous self-defense strategies. While some defenses are recent evolutionary innovations, others are ancient, with roots early in eukaryotic history. With a focus on antibacterial immunity, we highlight the evolution of pattern recognition receptors that detect bacteria, where diverse functional classes have been formed from the repeated use and reuse of a small set of protein domains. Next, we discuss core microbicidal strategies shared across eukaryotes, and how these systems may have been co-opted from ancient cellular mechanisms. We propose that studying antibacterial responses across diverse eukaryotes can reveal novel modes of defense, while highlighting the critical innovations that occurred early in the evolution of our own immune systems.

为了在一个由细菌主导的世界中生存，真核生物已经进化出许多自卫策略。虽然一些防御是最近的进化创新，但另一些则是古老的，起源于真核生物的早期历史。以抗菌免疫为重点，我们重点介绍了检测细菌的模式识别受体的进化，其中通过重复使用和重复使用一小部分蛋白质结构域形成了不同的功能类别。接下来，我们讨论了真核生物共享的核心杀菌策略，以及这些系统是如何从古老的细胞机制中选择出来的。我们建议研究不同真核生物的抗菌反应可以揭示新的防御模式，同时强调在我们自己的免疫系统进化早期发生的关键创新。