Preparation and properties of a therapeutic inter-alpha-trypsin inhibitor concentrate from human plasma.

Inter-alpha-trypsin inhibitor (ITI) is a serine protease inhibitor found in human plasma. Its antiprotease activity is due to bikunin which is effective in various types of experimental shock and pancreatitis. Therefore ITI, which releases bikunin by proteolytic cleavage, could be of therapeutic interest. A method for the large-scale isolation of ITI from human plasma is described. ITI was purified from the prothrombin complex concentrate (PCC) by diethylaminoethyl-Sepharose fast-flow chromatography followed by a chromatographic step on immobilized heparin designed to remove C4, factor X and protein C. With this procedure, which was performed under mild conditions, a homogeneous preparation of native ITI was obtained, as demonstrated by electrophoretic and chromatographic analyses. ITI maintained its biological activity, as exhibited by its specific antitryptic activity of 420 +/- 65 IU/g. In order to decrease or eliminate the risk of transmission of viral disease due to lipid-enveloped viruses, the process incorporated a solvent-detergent treatment. Animal studies on the final product revealed no adverse side-effects in terms of toxicity, thrombogenicity or hypotension. This preparation appears suitable for therapeutic evaluation in animal experimental models.