Adaptation of hybridoma cells to higher ammonia concentration

Using two mouse-mouse hybridoma cell lines, the response to ammonia step and serial changes was investigated in batch and continuous cultures with serum-free medium. The inhibitory effect of ammonia on cell growth depended on the cultivation mode, and differed markedly between cell lines. The cell line, 4C10B6 producing IgG monoclonal antibody against Pseudomonas, showed a high adaptation ability to ammonia. The 4C10B6 cells could grow under ammonia concentration as high as 21 mmol/l NH₄Cl with a viability of 80% in the continuous culture with serial increase in ammonia concentration. Whereas, in the batch culture with ammonia step change the cell growth completely ceased at 12 mmol/l NH₄Cl. The other cell line, TO-405 producing IgG monoclonal antibody against hepatitis B surface antigen, could not adapt to ammonia, and the cell growth did not occur at 9 mmol/l NH₄Cl even under the ammonia serial change.List of symbols D_Feed d^-1 Dilution rate of fresh feed medium (=F_o/V) - D_Out d^-1 Dilution rate of cell suspension (=F₁/V) - F₁ ml·d^-1 Volumetric discharge rate of cell suspension - F₀ ml·d^-1 Volumetric flow rate of fresh feed medium - k_D h^-1 Specific death rate - P mmol·l^-1 Product concentration - S mmol·l^-1 Substrate concentration in culture broth - S₀ mmol·l^-1 Substrate concentration in feed medium - t d Cultivation time - V ml Working volume of reactor - X₀ cells·ml^-1 Total cell density - X_V cells·ml^-1 Viable cell density - Y_P/S mmol·mmol^-1 Yield of product from substrate - Y_X/S cells·mmol^-1 Yield of cells from substrate - mmol·cell^-1·h^-1 Specific production rate - h^-1 Specific growth rate - mmol·cell^-1·h^-1 Specific consumption rate of substrate