Role of metabolic waste products in the control of cell proliferation and antibody production by mouse hybridoma cells.

In order to determine the factors limiting the proliferation and productivity of mouse hybridoma cells in batch/fed-batch cultures, we tested the influence of various environmental parameters on the growth of a model cell line VO 208. We observed that, among the major metabolic waste products, ammonium ions at concentrations superior to that present in the medium at the end of a batch culture do not exert a significant toxic effect on cell growth, whereas in contrast, lactic acid is cytotoxic at concentrations reached in cultures. Feeding of fructose instead of glucose during the stationary phase of the culture markedly prolongs the life span of the culture and enhances the antibody secretion accordingly.

Factors controlling cell proliferation and antibody production in mouse hybridoma cells: I. Influence of the amino acid supply.

To investigate the influence of medium amino acid resources on hybridoma cell proliferation and monoclonal antibody secretion, we first determined, in two different cell lines, the pattern of amino acid consumption. We then showed that complementation of each cell line by an amino acid solution prepared to cover its needs led in both cases to a marked increase in cell density and monoclonal antibody production. This observation suggests that the amino acid supply is one of the factors limiting cell growth and productivity in typical batch processes, and we demonstrated that a similar limitation occurs in a semicontinuous culture.

Comparison of various methods for monitoring hybridoma cell proliferation.

The design of a strategy for the control of large scale cultures of hybridoma cells requires the use of convenient indicators to monitor properly the evolution of the biomass. In order to select appropriate indicators, we have measured in parallel, in bulk cultures of mouse hybridoma cells, the evolution of several metabolic parameters together with those of cell density and viability. We observed that flow cytometry analysis gives an early indication of the proliferative capacity of the cell population.

Influence of amino acids on hybridoma cell viability and antibody secretion.

It is generally accepted that the phase of cell decline observed in batch culture of mammalian cells is related to exhaustion of medium nutrients (principally glucose and glutamine) and/or to waste products accumulation. In the present paper, we have studied the influence of glutamine on the proliferation of mouse hybridoma cells. We showed that repeated addition of glutamine prolonged the life span of the culture and significantly increased the secretion of monoclonal antibody.