Overexpression of bcl‐2, apoptosis suppressing gene: Prolonged viable culture period of hybridoma and enhanced antibody production

Human bcl‐2 DNA was introduced into mouse hybridoma 2E3 cells and expressed at a high level by using BCMGSneo vector, which reportedly amplifies as multiple copies in the cells independently of their chromosomes. The high expression of bcl‐2 in BCMGSneo‐bcl‐2 transfectants was confirmed by western blotting. In batch cultures, the overexpression of bcl‐2 raised the maximum viable cell density by 45%, delayed the initiation of apoptosis by 2 days, and prolonged the viable culture period by 4 days. The delayed initiation of apoptosis was detected by emergence of the ladder pattern on DNA electrophoresis and increase of the dead cell number. The bcl‐2 transfectants produced lgG1 fourfold per batch culture in comparison with 2E3 cells transfected with BCMGSneo but not with bcl‐2: a little less than twofold due to the improved survival of the cells and more than twofold due to the enhanced lgG1 production rate per cell of the bcl‐2 transfectants. The method to engineer hybridoma cells genetically with bcl‐2 using BCMGSneo vector for increasing viability and productivity would be widely applied for improving antibody productivity of hybridoma cultures. © 1995 John Wiley & Sons, Inc.

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