Energy consumption among static and proliferating hybridoma cell populations.
AuthorOkerlund, Linda Susan.
AdvisorGillies, Robert J.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractTo investigate the effects of proliferation on metabolism and cell product yields, proliferating and growth-limited EPOBF7 hybridoma cells have been compared as to their growth rates, energy demand, relative energy distributions, and monoclonal antibody (MAb) yield. Medium deprivation of leucine or serum was used to prevent growth. Energy consumption rates were determined in cell suspensions from rates of glucose consumption, lactate production, and oxygen utilization. In addition, the energy consumption of pathways critical to cell growth and survival were estimated from the relative decreases occurring in oxygen and glucose consumption upon pathway inhibition. The overall rate of energy consumption was significantly lower among growth-limited cultures. In addition, the distributions of oxidative and glycolytic energy among cellular synthetic pathways differed significantly between the culture conditions. Non-growing cultures also produced significantly lower antibody yields. Cell growth was also investigated using ³¹p nuclear magnetic resonance (NMR) spectroscopy of cells grown and maintained in bioreactor culture. Saturation transfer methods detected measurable transfer between inorganic phosphate (P(i)) and the gamma resonance of ATP. This transfer rate could be correlated with cellular growth rates within the reactor. Transfer of magnetization from the gamma resonance of ATP to P(i) was also detected, although the rate of this transfer did not appear to be related to the growth rate. The ratio of these transfer rates was consistently near 4. This information is believed to suggest the importance of other reactions through which ATP may donate its terminal phosphate. Cells in bioreactor culture were found to grow more slowly and produce lower levels of monoclonal antibody when compared to cells proliferating in suspension. such phenomena may be a function of diffusion limitations within the reactor such that the cells cannot obtain the nutrient supply required for optimal cell growth or product formation.