December’s issue of CSH Protocols is out, and one of our featured articles this month describes the isolation and growth of Bone Marrow-Derived Macrophages. Macrophages are specialized cells that carry out numerous tasks in the immune system such as phagocytosis, antigen presentation, cytokine production and migration. Cultured cells can be used to study these functions, as well as assays for gene expression, gene function and interaction with microbes. This protocol comes from Bo Porse and colleagues at the University of Copenhagen, and like all of our featured articles, can be freely accessed by subscribers and non-subscribers.