ITAM signaling by Vav family rho guanine nucleotide exchange factors regulates interstitial transit rates of neutrophils in Vivo

Background: In response to infection, neutrophils are quickly recruited from the blood into inflamed tissues. The interstitial migration of neutrophils is crucial for the efficient capture and control of rapidly proliferating microbes before microbial growth can overwhelm the host's defenses. However, the molecular mechanisms that regulate interstitial migration are incompletely understood. Methodology/Principal Findings: Here, we use two-photon microscopy (2PM) to study discrete steps of neutrophil responses during subcutaneous infection with bacteria. Our study demonstrates that signals emanating from ITAMcontaining receptors mediated by Vav family Rho GEFs control the velocity, but not the directionality, of neutrophil migration towards sites of bacterial infection. Conclusions/Significance: Here we show that during neutrophil migration towards sites of bacterial infection, signals emanating from ITAM-containing receptors specifically control interstitial neutrophil velocity.