Atomic force microscopy image of the pore. The best hiding place often lies behind enemy lines, as many bacteria such as the pathogens responsible for tuberculosis or typhoid have realized. They invade immune cells and can survive there, well hidden, for some time. To eliminate such invaders, the host macrophages can initiate a suicide program. Together with researchers at the Novartis Institute for Biomedical Research and ETH Zurich, the team led by Prof. Sebastian Hiller from the Biozentrum at the University of Basel has shown for the first time that a "death protein" perforates the cell membrane, resulting in macrophage bursting open. The re-exposed pathogens can then again be fought by the immune system.