Continuous antibody production by phytohemagglutinin-L-aggregated hybridoma cells

Phytohemagglutinin-L (PHA-L) induced aggregation of SP2 myeloma and antibod y-producing hybridoma cells. The aggregates were of diverse shapes, and maj or-axis length of the hybridoma aggregates was mostly 50-80 mu m at 1 mu g/ ml PHA-L and 100-150 mu m at 5 mu g/ml. PHA-L did not suppress growth rate at these concentrations. The aggregated cells had almost the same antibody productivity as that of non-aggregated cells in a static culture. Essential ly, identical results were obtained with soybean agglutinin (SBA). On the o ther hand, pokeweed mitogen (PWM) did not induce apparent aggregation at a concentration of 10 mu g/ml. These results suggest that lectin binding to p articular carbohydrate moiety on the cell surface is necessary for cell agg lutination. Using PHA-L, a 200-ml suspension culture of aggregated hybridom a cells was successfully performed in a spinner flask over 10 days. The agg regates were mainly globular with a diameter of 50-100 mu m at 1-2 mu g/ml PHA-L. The aggregation greatly enhanced settlement of hybridoma cells by gr avity, and medium exchanges were thereby easily performed in a short period . During a course of the semi-continuous culture, antibody concentrations o f culture medium were maintained at approximately 10 mu g/ml which was comp arable to that of static culture of the aggregated hybridoma cells. Thus, t he lectin aggregation is applicable to the separation of culture medium fro m anchorage-independent cells like hybridomas, and can be employed in a lar ge-scale commercial production of biologically active proteins. (C) 1999 El sevier Science B.V. All rights reserved.