IgG production in hybridoma batch culture: kinetics of IgG mRNA, cytoplasmic-, secreted- and membrane-bound antibody levels

During batch cultivation of the I.13.17. hybridoma cell line, there is a 15 to 20-fold decrease in the levels of cytoplasmic and membrane-bound mAb, and a 7 to 10-fold decrease in the cellular levels of kappa and gamma chain mRNAs, as the cells pass from the exponential into the decline phase of growth. The profile of the specific mAb production rate does not correlate with the kinetics of either the cytoplasmic mAb or the specific mRNAs throughout the culture. Flow cytometry analyses have revealed that dead cells, which account for 40 to 70% of total cells during the decline phase, might significantly interfere with the determination of cytoplasmic mAb levels of cell-lysates ELISA and with the calculation of the specific mAb production rate. Possible influences of these parameters on mAb synthesis and secretion during hybridoma batch culture are discussed.