title: Enhanced monoclonal antibody production by gradual increase of osmotic pressure.
abstract: The time length required for the adaptation of AFP-27 hybridoma cells to high osmotic pressure and the effect of a gradual increase of osmotic pressure on monoclonal antibody production were investigated. When the cells were subjected to an increase of osmotic pressure from 300 mOsmol kg-1 to 366 mOsmol kg- 1, the intracellular content of osmoprotective free amino acids reached a maximum level 6 h after the osmotic pressure was increased to 366 mOsmol kg-1. The same time period of 6 h incubation at 366 mOsmol kg-1 was required to obtain a high growth rate of AFP-27 cells at 440 mOsmol kg-1 when the cells were subjected to a two-step increase of osmotic pressure from 300 mOsmol kg-1 to 366 mOsmol kg-1 and then to 440 mOsmol kg-1. The time length for the physiological adaptation of the cells to 366 mOsmol kg-1 was consequently estimated to be 6 h. Osmotic pressure during batch cultivation was gradually increased from 300 mOsmol kg-1 to 400 mOsmol kg-1 with an adaptation time of at least 6 h. The specific growth rates following a gradual increase of osmotic pressure were higher than those at a constant osmotic pressure of 400 mOsmol kg-1, while the specific monoclonal antibody production rate increased with the increase in the mean osmotic pressure. As a result, the cells grown under a gradual increase of osmotic pressure produced higher amounts of monoclonal antibodies than did those grown under constant osmotic pressure.
authors.affiliation: International Center for Biotechnology, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka, 565, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Lin
authors.forename: M
authors.initials: M
authors.lastname: Takagi
authors.forename: Y
authors.initials: Y
authors.lastname: Qu
authors.forename: P
authors.initials: P
authors.lastname: Gao
authors.forename: T
authors.initials: T
authors.lastname: Yoshida