title: Optimization of cell culture conditions for production of biologically active proteins.
abstract: We investigated the basic technology of cell culture conditions for production of useful substances such as cytokines, and related proteins produced by Namalwa cells. Namalwa cells (Klein, 1972), human B lymphoblastoid cells, were used for large scale production of alpha-interferon (Klein, 1979). Namalwa KJM-1, a subline of Namalwa cells, adapted to serum- and albumin-free medium, can grow at a high density above 1 × 10(7) cells/ml in suspension mode by the use of a perfusion culture system, Biofermenter(™), containing a cone-type cell-sedimentation column as cell separator (Sato, 1983).Several kinds of cytokine cDNA can be introduced and expressed in Namalwa KJM-1 cells (Miyaji, 1990a,b,c). Some of these were produced in large quantities by use of a gene amplification method with dhfr (Miyaji, 1990c), even though the Namalwa KJM-1 cells contained endogenous dhfr genes. For stable production of the target protein, Namalwa KJM-1 cells are very useful host cells, because they have no effective endogenous protease activity in the conditioned medium.Using Biofermenter with micro-silicone fibers and a dialysis system, the specific productivity of the target proteins was not depressed at a high cell density.
authors.affiliation: Tokyo Research Laboratories, Kyowa Hakko Kogyo Co., Ltd., 3-6-6 Asahi-machi, 194, Machida-shi, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hosoi
authors.forename: H
authors.initials: H
authors.lastname: Miyaji
authors.forename: M
authors.initials: M
authors.lastname: Satoh
authors.forename: T
authors.initials: T
authors.lastname: Kurimoto
authors.forename: A
authors.initials: A
authors.lastname: Mihara
authors.forename: N
authors.initials: N
authors.lastname: Fujiyoshi
authors.forename: S
authors.initials: S
authors.lastname: Itoh
authors.forename: S
authors.initials: S
authors.lastname: Sato