Functional alpha 1 protease inhibitor produced by a human hepatoma cell line.
Alpha 1 protease inhibitor antigen was identified in the culture medium of the human ascites hepatoma cell line SK-HEP-1. Trypsin inhibitory activity and alpha 1 Pl antigen accumulated in serum-free medium concomitantly over a period of several days. Radioactive alpha 1 Pl antigen was detected in conditioned medium from cultures supplemented with 35S-L-methionine, indicating a synthesis and release of the protein. Alpha 1 Pl antigen in conditioned medium appeared to be antigenically identical to that in human plasma, and the newly synthesized (radiolabeled) antigen co-migrated with plasma, alpha 1 Pl after immunoelectrophoresis or SDS-polyacrylamide gel electrophoresis. Moreover, evidence is presented that the synthesized inhibitor exhibits functional activity, since the 35S-labeled alpha 1 Pl in conditioned medium complexes with trypsin. We conclude that SK-HEP-1 cells in culture produce functionally active alpha 1 Pl which may be identical to that in plasma.
D000818:Animals; D000941:Antigens; D006528:Carcinoma, Hepatocellular / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D003470:Culture Media; D006041:Goats; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007123:Immunoelectrophoresis, Two-Dimensional; D008113:Liver Neoplasms; D011817:Rabbits; D013045:Species Specificity; D014361:Trypsin Inhibitors / Q000494:pharmacology; D000515:alpha 1-Antitrypsin / Q000096:biosynthesis* / Q000276:immunology / Q000378:metabolism
D000941:Antigens; D003470:Culture Media; D007106:Immune Sera; D014361:Trypsin Inhibitors; D000515:alpha 1-Antitrypsin