Fig. 2.

The positive control indicates osteoarthritis (OA) fibroblasts migrating towards 3% fetal bovine serum (a fibroblast chemoattractant). The quantity of background migration is indicated by the negative control, phosphate-buffered saline (PBS). Migration towards several concentrations of fractalkine (FKN) are shown. This graph is representative of assays performed on OA fibroblasts obtained from 10 different patients, where FKN induced significant migration in all cases. Bars and error bars represent the mean ± standard error of the mean of counts summed from three high powered fields (HPFs). An asterisk indicates significant migration above the negative control PBS.