Journal of leukocyte biology
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Neutrophil (PMN) migration into the peritoneal cavity in response to fecal peritonitis is an important mechanism of host defense against bacterial invasion. We show that the murine C-X-C (PMN-specific) chemokine, macrophage inflammatory protein-2 (MIP-2), on intraperitoneal injection in mice, causes PMN migration into the peritoneum. MIP-2 mRNA and protein were expressed by peritoneal leukocytes after cecal ligation and puncture (CLP) in mice and neutralization of MIP-2 reduced peritoneal PMN migration. ⋯ In a subsequent experiment, mast cell-deficient mice and their normal controls were then injected intraperitoneally with MIP-2 or underwent CLP. Significantly fewer PMNs migrated into the peritoneal cavity in the mast cell-deficient mice after MIP-2 injection or CLP. Thus, our findings indicate that mast cells and MIP-2 are necessary for PMN migration into the peritoneum in response to intra-abdominal infection, and that MIP-2 appears to facilitate this through an increase in TNF-alpha release.