Speaker
Description
Neutrophils, the most abundant leukocytes in the human body, serve as the first line of defense against infection and injury. They locate and eliminate pathogens through a “search-and-run” strategy, consisting of an initial random search phase followed by a directed migration toward chemical cues. While the directed phase has been extensively studied, the mechanisms underlying the random search mode remain poorly understood. In this study, we perform single-cell observations of neutrophils using phase-contrast and fluorescence microscopy to monitor cell morphology and nuclear dynamics during both searching and target-directed behaviors. Using manual tracking in ImageJ Fiji, we quantified neutrophil motility during the search phase by analyzing centroid trajectories, migration parameters, and time-dependent morphological changes observed during polarization and protrusion–retraction cycles. Our analysis reveals distinct morphological fluctuations and nuclear movements that may underlie efficient environmental exploration prior to chemotactic engagement. These results provide new insight into the physical and cellular basis of neutrophil search strategies and may contribute to a deeper understanding of immune cell navigation in complex tissue environments.
