Monocyte migration inhibitory factor synthesis and gene expression in particle-activated macrophages

This study analysed MIF mRNA and protein expression in human macrophages ex posed in vitro to polymethylmethacryate and titanium alloy particles, MIF l evels released from macrophages without exposure to particles mere in the r ange of 2-4 ng/ml, Exposure of macrophages to particles as demonstrated inc reased MIF release at 0.075%-0.225% v/v particle concentration, which was m aximal at 12-24 h, MIF mRNA signal levels in cells with and without particl es at a concentration of 0.075% showed no significant differences in a time course experiment. The profile of MIF release in response to increasing pa rticle concentration coincided with increased release of lactate dehydrogen ase, The viability of the cells was unchanged by the addition of particles as determined by 3H-thymidine uptake. These data suggest that MIF expressio n may represent an independent macrophage response to locally high particle concentrations. (C) 2000 Academic Press.