Measuring efferocytosis by intraperitoneal clearance assay.

Efferocytosis is a critical process by which phagocytes identify, engulf and clear apoptotic cells, thereby preserving immune tolerance and tissue homeostasis. While in vitro assays have advanced our understanding of the molecular mechanisms underlying apoptotic cell clearance, they lack the complexity of the physiological environment. This chapter presents a detailed in vivo approach for assessing efferocytosis by mouse peritoneal macrophages using the intraperitoneal (IP) clearance assay. By administering fluorescently labelled apoptotic Jurkat T cells into the peritoneal cavity, this method enables the quantification of apoptotic cell uptake in a native tissue context, capturing the influence of local immune signals, stromal interactions and systemic factors. This protocol is compatible with genetic and pharmacological manipulations, allowing researchers to investigate how various interventions affect efferocytic capacity. Overall, this approach provides a robust and physiologically relevant framework for studying efferocytosis and its implications in both homeostatic and pathological settings.