Batch cultures of a mouse/mouse hybridoma cell line secreting a dimeric IgA were performed in combination with a membrane process for the continuous removal of ammonia from the culture medium. The latter involves hydrophobic porous membranes with an assocd. pH gradient. The process was efficient in reducing the ammonia concn. by approx. 50% by comparison to control expts. Two series of expts. were performed with an initial glutamine concn. of 4 mM and 10 mM, resp. The growth characteristics, antibody productivity, and quality of antibody assayed by Western blotting were not changed by ammonia removal; however, the cellular energy metab. was affected by redn. of ammonia levels. At the lower initial glutamine concn., ammonia removal caused an increased glutamine consumption and reduced lactate prodn. No effect upon glucose uptake was obsd., thus resulting in a considerably reduced yield of lactate from glucose. At the high initial glutamine concn., the reduced ammonia concn. led to a decrease in glucose and glutamine consumption as well as lactate prodn. This resulted in only a slight increase in the yield of lactate from glucose. Despite the abundance of literature concerning ammonia inhibition of mammalian cell cultures, little has been reported concerning the effect of continuous ammonia removal from such cultures. [on SciFinder (R)]