High Yields of Monomelic Recombinant beta-interferon From Macroporous Microcarrier Cultures Under Hypothermic Conditions

摘要

Macroporous microcarriers such as Cytopore entrap mammalian cells in a mesh network allowing growth to high cell concentrations in a protected environment within a stirred culture.Chinese hamster ovary(CHO)cells producing recombinant human beta-interferon(IFN-beta)and grown in Cytopore microcarriers showed a 2.6-to 2.8-fold increase in the volumetric product titer compared with cells grown in an equivalent suspension culture.In an attempt to maximize production of IFN-beta,microcarrier cultures were subjected to a low temperature regime.Low temperature culture conditions(32°C)have been shown previously to enhance cell specific productivity in suspension cultures although at reduced cell growth rates.These conditions can be optimized by a timely shift from physiological to hypothermic conditions during the culture run to maximize volumetric protein production.In the case of IFN-beta production the lower temperature has the added advantage of stabilizing the product and reducing intramolecular aggregation.Using a biphasic temperature-shift regime from 37 to 32°C the volumetric production of IFN-beta was enhanced to 4.2-fold compared with a single temperature suspension culture in a controlled bench-top bioreactor.Furthermore,the degree of intramolecular aggregation of IFN-beta was reduced significantly(59%)compared with control cultures,largely due to the lower temperature but also partially due to the presence of microcarriers.These results indicate that the hypothermic conditions in a Cytopore culture had a combined and possibly synergistic effect of increasing volumetric production of the recombinant protein.