Sustained high-level production of murine chemokine C10 during chronic inflammation

The murine CC chemokine C10, a macrophage chemoattractant, has been shown to have an unusually restricted expression pattern in cultured cells (LPS non-responsive, IL-4 inducible). Its occurrence in vivo has not been characterized. Here the authors employ immunocytochemistry to demonstrate that C10 is expressed in inflammatory macrophages during irritant peritonitis. In addition, C10 was found to be a constitutive component of eosinophils. Peritoneal inflammation led to the accumulation of sufficient C10 (> 10 nM) to permit detection in exudate fluid. This accumulation did not begin until 24 h after challenge, and was sustained through at least day 10 of the inflammation. In contrast, MIP-1α gene expression was earlier and transient. These kinetic features are consistent with earlier in vitro findings, suggesting that C10 is not a 'first-wave' chemokine and may play a role related to chronic stages of host defence reactions.