Neutrophil Recruitment: From Model Systems to Tissue-Specific Patterns

Neutrophil recruitment is vital for host defense, but also relevant in pathological inflammatory reactions such as sepsis. Model systems have been established to examine different steps of the leukocyte recruitment cascade in vivo and in vitro under inflammatory conditions. Recently, tissue-specific recruitment patterns have come into focus, requiring modification of formerly generalized assumptions. The aim of this review is to summarize existing models of neutrophil recruitment and to point out recent discoveries in organ-specific recruitment patterns. New techniques show that previously-stated assumptions of integrin activation and tissue invasion may need revision. Similarly, neutrophil recruitment to specific organs can rely on different organ properties, adhesion molecules and chemokines. To advance our understanding of neutrophil recruitment, organ-specific intravital microscopy methods are needed.