Mopping up chemokines

In both Iraq and the immune system, it's not the initial victory but the subsequent cleaning up that is the hardest part. Now, Amiram Ariel, Charles Serhan (Harvard Medical School, Boston, MA), and colleagues show that the mess after an infection is cleared up in part by dying cells.

This very act of cell death—notably of neutrophils and T cells—is one way of actively resolving an inflammatory event. But the signals that first drew immune cells to the site of inflammation also need to be destroyed: chemicals via enzymatic degradation and proteins and peptides by other means. Now, the Boston team shows that some of these chemokine proteins are mopped up by apoptotic cells. These dying cells turn up expression of their CCR5 chemokine receptors even as the cells are about to be engulfed by macrophages.

CCR5...