Materials and Methods

Calf lung surfactant extract (CLSE)(stock solution 35 mgt ml in saline) was generously provided by G. Enhorning (Buffalo, NY). Purified human fibrinogen (clottability~ 99%; containing minor amounts of F Xlll) and human antithrombin ill (Kybeminf') were gifts from N. Heimburger (Behringwerke, Marburg, Germany). Dog surfactant protein (SP)-A (> 90% purity by sodium dodecy1 sulfate polyacrylamide gel electrophoresis [SDS-PAGED was provided by U. Pison (Berlin, Germany). Human thrombin (specific activity 120 U/mg) was purchased from Boehringer (Mannheim, Germany). GLY-PRO-ARG-PRO, monoclonal antibody to human fibrinogen (F-2506;~ 40 mg/ml protein; stock solution diluted 1: 100in phosphate-buffered saline [PBS], pH= 7.4) and bovine albumin were obtained from Sigma (Munich, Germany). Arvin (80 U/ml) was received from Twyford Labs (London, England). Maxisorpf and Polysorp" microtiter plates were obtained from Nunc (Wiesbaden, Germany). Heparin (Liquemin®) was purchased from Roche (Grenzach-Whylen, Germany). 125I-human fibrinogen (91.7/-, Ci/mg), 14C_ dipalmitoylphosphatidylcholine (DPPC)(154/-, Ci/mg)," Cvdioleoylphosphatidylcholine (DOPC)(134/-, Ci/mg)," Csstearic acid (54.8 j. tCi/mg)," Csglycerol-Scphosphate (795/-, Ci/mg), and 3H-pa1mitic acid (206/-, Ci/mg) were all provided by Amersham Buchler (Braunschweig, Germany)." Cedipalmitoylphosphatidic acid (DPPA)(156.5/-, Ci/mg) and 3H-arachidonic acid (76 Ci/mmol) were from New England Nuclear (Bad Homburg, Germany). All other chemicals were purchased in highest quality from Merck (Darmstadt, Germany).