LAUSR

Accessibility and ease of leukocyte extraction led to the peritoneal cavity becoming one of the most commonly used sites to obtain primary macrophages for in vitro analyses and to model inflammation. However, the advent of multiparameter flow cytometry has highlighted the complexity of the mononuclear phagocyte compartment of the serous cavities, which contains multiple populations of macrophages, dendritic cells, and monocytes that coexist with other leukocytes. Given that serous cavity macrophages are known to contribute to both the maintenance of tissue homeostasis and the generation and resolution of inflammation, a thorough understanding of the cells that comprise the peritoneal macrophage compartment, how to identify them from related mononuclear phagocytes, and the processes required to isolate them for ex vivo and in vitro analysis is important if we are to fully understand their function in different tissue contexts. Here, we detail commonly used methods to isolate leukocytes from the peritoneal and pleural cavities and describe reliable strategies to identify the discrete populations of mononuclear phagocytes in these sites.