METHODS FOR REDUCING THE AMMONIA IN HYBRIDOMA CELL-CULTURES

The factors which limit the proliferation of eukaryotic cells in vitro are still not well known. Ammonia is believed to be toxic for mammali an cell proliferation and secretion. We have tried two approaches to r educing the ammonia in the medium. We first limited the ammonia produc ed by the cells by replacing glutamine by glutamate. Then, we used two chemical engineering methods to eliminate accumulated ammonia. In one the used medium was passed through a natural cation exchanger: the cl inoptilolite. In the other, the culture medium was passed through a hy drophobic microporous hollow fiber module. Replacing the glutamine by glutamate reduced the medium ammonia concentration. The physicochemica l removal of ammonia induced a better cell growth, but not a better sp ecific antibody secretion.