Dr Pramuk Keerthisinghe, Postdoctoral Fellow, Department of Physiology

The immune system's ability to fight bacteria varies throughout the day, often peaking during an organism's active phase. Our research focuses on neutrophils, key immune cells, and how their internal circadian clocks regulate their antibacterial activity. Using genetically modified zebrafish, we found that neutrophils have alight-responsive circadian timer that enhances their ability to kill bacteria during the daytime. The gene per2 is crucial for this process, as it boosts the production of bactericidal reactive oxygen species (ROS) and inflammatory signals in response to infection.Another circadian clock gene, cry1a, has the opposite effect. Our findings highlight the importance of the circadian rhythm in optimising immune defence against bacterial infections during the day and provide ways our immune system can be primed for infectious challenges.