How to eat something bigger than your head

Macrophage phagocytosis, the engulfment of large particles, is important for host defense against infection and for the removal of dead cells. These phagocytes can internalize particles larger than themselves, obtaining membrane from internal pools including recycling endosomes. Desjardins and coworkers report in this issue of Cell (Gagnon et al., 2002) that the endoplasmic reticulum is a major reservoir of membrane for phagocytosis, an observation that may shed light on a number of conundrums in immunology.