(A) Coculture experiments with myeloma cell lines and Saos-2 cells under the following conditions: (1) JJN-3 in the upper chamber of tissue inserts and Saos-2 cells in the lower. (2-6) Physical contact between JJN-3 and Saos-2 cells, (2) with no addition, (3) in the presence of 1:1000 or (4) 1:2000 rabbit anti-HGF serum, and (5) in the presence of 1:1000, or (6) 1:2000 dilutions of preserum. (7) OH-2 cells in the upper chamber of tissue inserts and Saos-2 in the lower. (8) Physical contact between OH-2 and Saos-2 cells.(9) Saos-2 cells alone without myeloma cells. Supernatants were harvested after 48 hours. (B) The right panel shows the following coculture conditions with physical contact: (1) Saos-2 alone, (2) coculture of JJN-3 and Saos-2 cells, (3) coculture of heparin-washed JJN-3 and Saos-2 cells, (4) coculture of OH-2 and Saos-2 cells, and (5) OH-2 cells incubated with 1 μg/mL HGF followed by extensive washing before coculture with Saos-2 cells. Supernatants were harvested after 12 hours. In all experiments, IL-11 was measured in duplicates by ELISA. Data are means ± SD from 1 representative experiment of 3.