Chemokine production by various cell lines. Production of MCP-1, IL-8, RANTES, IP-10, and MIP-1β was measured by ELISA. Various cell lines (1 × 105/ml) were cultured for 24 h with 2 ml DMEM containing 5% FBS, and supernatants were collected. The contents of (A) MCP-1, (B) IL-8, and (C) RANTES are shown; MIP-1β and IP-10 were not detected (less than 10 pg/ml). 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 from triplicates of one representative experiment out of three with similar results. Statistical analysis was performed with the Student t test. *P < 0.05 and **P < 0.01.