Effect of feeding rate on monoclonal antibody production in a modified perfusion-fed fermentor

Previously we described a perfusion system for production of high yields of monoclonal antibodies in a fermentor. This system incorporated a cylindrically shaped, stainless steel filter mounted around the stirring shaft for retention of cells within a 1 liter fermentor. Modification of this filter by increasing the pore size from 5 micron to 10 micron decreased its tendency to clog and allowed continuous operation for about 3 weeks. Fresh culture medium, containing 6.5 mg glucose/ml and 3% horse serum, was supplied continually at two different perfusion rates, 850 and 1100 ml/day. Spent culture medium containing monoclonal antibody was harvested concomitantly. Highest cell density (5 X 10(7)/ml) and best antibody yield (1.7 g/l culture per day) were obtained at the higher feeding rate.