Stopping the swarm Neutrophils play a major role in the early immune response and are recruited in large numbers into inflamed and infected tissues. By secreting chemoattractants that bind G protein–coupled receptors (GPCRs) on neighboring cells, neutrophils coordinate their behavior as a swarm. Less clear is how this auto-amplifying swarming activity is ultimately turned off. Kienle et al. show that desensitization of these GPCRs by the same chemoattractants by GPCR-kinase 2 (GRK2) is one way in which these swarms are shut down (see the Perspective by Rocha-Gregg and Huttenlocher). Unexpectedly, mice with GRK2-deficient neutrophils showed impaired rather than enhanced bacterial clearance. The heightened scanning ability of GRK2-deficient neutrophils may come at the cost of suboptimal phagocytosis and containment of bacteria. Science , abe7729, this issue p. eabe7729 ; see also abj3065, p. 1262