Figure 9.

Mesothelial cells generate bikunin from serum IαI. Heat-treated human serum (10%) was incubated in Medium 199 in the presence and absence of confluent human peritoneal mesothelial cells at 37°C for 24 hours. The supernatants were collected, and the cell layer was extracted with 1% SDS. Samples of the supernatant before and after digestion with chondroitin ABC lyase were electrophoresed on a 5 to 15% gel, and a Western blot was generated with anti-human IαI antibody. a: The supernatants obtained in the absence (lanes 1 and 2) or presence (lanes 3 and 4) of cells. Prestained molecular mass markers are indicated with arrowheads and released H chains (60 kd) and free bikunin (50 kd) with arrows. The open arrows indicate the core protein released after incubation with chondroitin ABC lyase. b: Control incubation (lane 5) and cell extract of mesothelial cells incubated with serum (lane 6). Prestained molecular mass markers are indicated with arrowheads and bound proteins with arrows.