Extravascular neutrophil migration is poorly characterized
in vivo. To test the hypothesis that this migration is a non-random process, we used videomicroscopy to monitor neutrophils in irises
of living mice with endotoxin-induced uveitis (EIU). Paths of individual cells were analyzed. Nearly all of these cells were
moving in divergent directions, and mean displacement plots indicated that the predominant movement was random. The paths
of some cells were fit to bivariate autoregressive integrated moving average models that revealed at least two modes of movement:
random search and linear trend. Cell speed was significantly reduced by the actin inhibitor, cytochalasin D. The pattern of
migration for neutrophils is in marked contrast to what we previously described for antigen-presenting cells in the iris,
but somewhat resembles recent descriptions for T cells within a lymph node. Characterization of extravascular migration of
neutrophils has important implications for understanding infection and immunity.
Key words intravital microscopy - leukocyte trafficking - uveitis
Planck and Becker contributed equally.