Abstract: A method for producing influenza virus on large scale is provided. A method for propagating influenza virus which comprises, after removing or decreasing a trypsin inhibitor secreted into culture of MDCK cells (cell line derived from dog kidney) by washing with a culture medium or a buffer, inoculating influenza virus into said cells and culturing said influenza virus-inoculated cells in a culture medium supplemented with trypsin.

Abstract: A method for producing influenza virus on large scale is provided. A method for propagating influenza virus which comprises, after removing or decreasing a trypsin inhibitor secreted into culture of MDCK cells (cell line derived from dog kidney) by washing with a culture medium or a buffer, inoculating influenza virus into said cells and culturing said influenza virus-inoculated cells in a culture medium supplemented with trypsin.

Abstract: The present invention provides for a process for preparing a recombinant human thrombin. A process for preparing a recombinant human thrombin which comprises: (1) obtaining a transfectant cell producing a human prothrombin by introducing an expression vector, wherein a gene fragment coding for a human prothrombin gene is incorporated, into an animal cell; (2) purifying a human prothrombin from the culture of the transfectant cell above by an anion exchanger; (3) converting the purified human prothrombin into a human thrombin by subjecting said human prothrombin to the action of ecarin; and (4) purifying the human thrombin from the solution after treatment with ecarin by an affinity method using benzamidine and a cation exchanger, and human thrombin obtained by said process, and a CHO cell that produces human prothrombin.

Abstract: Multimers of human serum albumin are removed from a solution of human serum albumin containing the multimers by bringing the human serum albumin solution into contact with an anion-exchanger equilibrated with a buffer containing a salt in a concentration ranging from 10 to 150 mM and having a pH value ranging from 5 to 9.5.

Abstract: A method for preparing human serum albumin comprises the step of heat-treating a human serum albumin solution containing contaminants at a pH value in the proximity to the isoelectric point of the contaminants.

Abstract: A method for converting a multimer of human serum albumin into monomers thereof comprises the step of treating the multimer with an alkaline solution. This method permits the efficient and quite simple conversion of human serum albumin multimers into monomers thereof at a low cost.

Abstract: Multimers of human serum albumin are removed from a solution of human serum albumin containing the multimers by bringing the human serum albumin solution into contact with an anion-exchanger equilibrated with a buffer containing a salt in a concentration ranging from 10 to 150 mM and having a pH value ranging from 5 to 9.5.

Abstract: A method for preparing human serum albumin comprises the step of heat-treating a human serum albumin solution containing contaminants at a pH value in the proximity to the isoelectric point of the contaminants.

Abstract: A human Activated Protein C preparation with a high specific activity of 3500 U/mg or more and substantially free from thrombin or other proteases which can convert Protein C into Activated Protein C is provided. A process for preparing this human Activated Protein C, which involves, contacting a solution of human Activated Protein C, after activation of Protein C with thrombin or other activating protease, with a cation exchanger to allow for adsorption of both thrombin or another activating protease and Activated Protein C to the cation exchanger followed by elution of the human Activated Protein C alone.