Platelets, known for slowing bleeding upon injury, may also play a key role in immunity, according to a new study that found platelets in the livers of mice engulfed blood-borne bacteria, protecting the animals against microbial infection. Previous evidence showing that platelets express pathogen-combating receptors and can kill bacteria in vitro also supports this notion, but the new work “emphasizes that platelets play a day-to-day role in innate immune defense by helping remove bacteria in the liver,” said Steve Watson, a platelet cell biologist at the University of Birmingham, who did not participate in the research.
