MDC protein expression in human monocyte–derived macrophages and unstimulated epithelial cell lines. Monocytes were differentiated into macrophages by incubation on tissue culture plastic for 6 d. LDL or oxidized LDL was then added for an additional 3 d. Culture supernatants from these macrophages or from epithelial lines were passed over heparin– Sepharose columns, and MDC was eluted with 0.6 M NaCl, fractionated by SDS-PAGE, and reacted with an mAb raised against recombinant MDC produced in bacteria. (Top) The Coomassie stained gel of the heparin– Sepharose elutates. (Bottom) The Western blot. Lanes 1, CHO-derived MDC; 2, A549 epithelial cell; 3, T84 epithelial cell; 4, macrophage, day 6; 5, macrophage, day 9; 6, macrophage plus LDL, day 9; 7, macrophage plus oxidized LDL, day 9. Arrows indicate the migration of MDC.