Relationship between the particles abilities to induce MIP-2 release and apoptosis. The figure displays the relative abilities of all the tested particles to induce MIP-2 release plotted against their abilities to induce apoptosis. The values are based on AUCs of relative increases in particle-induced MIP-2 release and apoptosis from the concentration-effect curves in Figs. 1A, 1E, 3A, 3C, 4B and 4D (concentration range: 0–600 μg/ml). Each point depicts the mean of 3–7 independent experiments. The figure also displays the result from a correlation analysis of the relative abilities to induce MIP-2 release versus apoptosis, as well as the linear regression line for the same data set with 95% confidence intervals.