This video shows an example of how we visualize and quantify efferocytosis. During efferocytosis, apoptotic (dying) cells are taken up piecemeal by the engulfing macrophage. TO visualize this process we pre-label the cytosol of the apoptotic cell with a protein reactive fluorophore such as Cell Proliferation Dye e670, and coat the surface of the apoptotic cell with NHS-biotin. The apoptotic cells are then ‘fed’ to the macrophages, and after the desired period of time, the sample fixed and any non-internalized apoptotic cell material labelled with fluorescent streptavadin.
This video was captured 90 minutes after the apoptotic cell was fed to the macrophage. About half of the cell has been engulfed by the macrophage, and with the other half awaiting engulfment.