Stimulation of monoclonal antibody production of hybridoma cells by butyrate: evaluation of a feeding strategy and characterization of cell behaviour

Experiments, earlier performed in our laboratory, showed the stimulating effect of butyric acid on monoclonal antibody production by hybridoma cells. Its simulaneous inhibitory effect on cell growth can however compensate for this, so that no increase of monoclonal antibody titer might be obtained. We show in this article an experiment with addition of butyric acid in the middle of the growth phase of a batch culture, as a strategy to take real profit of such an addition by a significant increase of final monoclonal antibody concentration. Indeed, in this way a significant cell density could be obtained before the addition of butyric acid, while the remaining culture time was still sufficiently long for its action, resulting in a two fold increase of final monoclonal antibody titer. The experiment was carried out in a 2 L bioreactor, showing the real practical interest of such an addition for the large scale production of proteins. Furthermore, analysis of the produced IgG by SDS-PAGE and Western blot did not reveal structural changes after stimulation by butyric acid. An original point of our study is the characterization of the cell behaviour, by flow cytometry and other related techniques, leading to a better insight in the effect of the butyric acid addition on cell growth and monoclonal antibody production. Although there exists a lot of knowledge about the effects of butyrate on cells in the field of molecular biology, our article is at our knowledge one of the first to show some of its effects on cell behaviour in bioreactor culture, carried out under perfectly defined and controlled conditions, and with the aim to stimulate monoclonal antibody production.