SUBSTANTIAL OVERPRODUCTION OF ANTIBODIES BY APPLYING OSMOTIC-PRESSUREAND SODIUM-BUTYRATE

Much of the current cell technology has enabled increased antibody pro duction levels due to judicious nutrient feeding to raise cell densiti es and design better bioreactors. This study demonstrates that hybrido mas can be hyperstimulated to produce higher immunoglobulin (I) levels by suppressing cell growth and increasing culture longevity through a daptation to higher osmolarity media and addition of sodium butyrate. Prior to adaptation, cells placed in higher osmotic pressures (350 and 400 mOsm) were severely suppressed in growth down to 25% of the contr ol (300 mOsm), although total Ig titers achieved were similar to the c ontrol, approximately 140 mg/L. After a week of adaptation to 350 and 400 mOsm media, cell growth was not as dramatically suppressed, but co nsiderably higher Ig levels were attained at these elevated osmolariti es. The highest yield of 265 mg/L was obtained at 350 mOsm compared to 140 mg/L at 300 mOsm, while maximum viable cell numbers dropped from 35 x 10(5) cells/mL to 31 X 10(5) cells/mL and culture longevity was e xtended by 20 h more than the control. Sodium butyrate, known to enhan ce protein production in other cell types, was then supplemented at a range of concentrations between 0.01 and 0.4 mM to the 350 mOsm cultur e to further enhance the Ig levels. Butyrate at a concentration of 0.1 mM, in combination with osmotic pressure at 350 mOsm, further elevate d the Ig levels to 350 mg/L. Concomitantly, maximum viable cell number s were reduced to 22 x 10(5) cells/mL, but culture longevity was exten ded by 40 h in the 0.1 mM butyrate supplemented culture compared to th e control condition. Specific antibody productivity, q(Mab), continued to stay high during the stationary phase and was further elevated dur ing the decline phase: thus, overall Ig levels can be increased by 2.3 times by combining osmotic pressure and butyrate treatment. (C) 1993 John Wile & Sons, Inc.