Macrophage Phagocytosis Assay of Staphylococcus aureus by Flow Cytometry

This protocol describes a straightforward technique to evaluate the phagocytotic capacity of murine macrophages for Staphylococcus aureus (S. aureus). By staining S. aureus with Hexidium Iodide and staining murine bone marrow-derived macrophages (BMDMs) with FITC, the macrophage bacterial up-taking ability can be rapidly analyzed by flow cytometry. S. aureus is a Gram-positive bacteria causing severe human and animal infections. Host immune cells such as macrophages serve to eliminate S. aureus by phagocytosing the pathogen and save the host from life-threatening diseases. Study of host macrophage ability to phagocytose S. aureus is important for understanding the host-pathogen interaction and can help to elucidate the pathogenesis of S. aureus infection. This protocol may also be applied for macrophage phagocytotic assay of other gram-positive bacteria.