An assay of monocyte migration was performed using supernatants of various cells. Each cell line (1 × 10/well) was cultured in six-well culture plates with 2 ml DMEM supplemented with 5% FBS. Supernatants were collected after 24 h of incubation, and were used for assay. Migrated cells were stained with anti-CD14 mAb, then the number of migrated CD14 cells was assessed by flow cytometry. RA6/1, RA8/3, and Sy77 are RA SCLs, OA5/26 is a SCL from OA, and FBHG is a skin fibroblast line. The mean and SEM were calculated with data from 11 independent experiments. Statistical analysis was performed with the paired Student test. < 0.05 and < 0.01.