Macrophages are immune system cells that help to destroy germs such as bacteria by engulfing and digesting them. Some bacteria, however, are able to avoid destruction by getting into the macrophage’s inner cytosol compartment. University of North Carolina School of Medicine researchers have discovered that a macrophage detects this escape into the cytosol and responds by triggering its own destruction.
According to researcher Edward Miao, “In the macrophage, this cell death, called pyroptosis, expels the bacterium from the cell, exposing it to other immune defense mechanisms.” Once the bacteria are free from the self-destroyed macrophage, lymphocytesand other immune cells are able to destroy them. The enzyme that initiates the cell suicide pathway in macrophages has been identified as caspase-11.