Cytotoxic T lymphocytes (CTLs) are versatile killers. When they detect a target—a cell infected by a virus or deranged by cancer—they can release soluble proteins that punch holes in a targeted cell’s membrane, exposing the targeted cell’s innards to toxic enzymes that cause it to self-destruct. But that’s not all, report scientists based at the University of Oxford. According to these scientists, CTLs may release supramolecular attack particles (SMAPs), which may attach to (and destroy) a target cell straightaway, or linger in the intracellular environment autonomously. The upshot is that SMAPS—glycoprotein shells packed with “explosive” cytotoxic proteins—may act as hand grenades or land mines.