Fig. 6: Schematic representation of neutrophil and macrophage cell death under homeostatic and Salmonella Typhimurium (ST) infection conditions.

Under homeostatic conditions, neutrophils and macrophages undergo turnover through regulated cell death mechanisms, including apoptosis, pyroptosis, and necroptosis. Initially, upon S. Typhimurium infection, there is a rapid increase in neutrophil and macrophage numbers due to emergency hematopoiesis. However, as early as 3 h post-infection, neutrophils begin to undergo all three types of cell death: apoptosis, pyroptosis, and necroptosis, while macrophages predominantly die via necroptosis. This shift highlights the dynamic and differential regulation of phagocyte cell death in response to bacterial infection.