How bacterial immune systems sense phage infection.

Bacterial immune systems detect phage infection primarily through sensing phage nucleic acids, proteins, and host process perturbations, enabling rapid immune activation.

• Why it matters: Understanding how bacteria recognize phage invasion fills a critical knowledge gap in microbial immunity and can inform strategies to combat bacterial infections or phage therapy resistance.
• What they did: The authors review experimental methods used to identify phage triggers and categorize them into three classes—nucleic acids, proteins, and host process disruptions—highlighting principles of immune sensing.
• The result: This framework clarifies how bacteria distinguish self from non-self, advancing our understanding of immune detection mechanisms and potentially guiding the development of novel antimicrobial strategies.