ISSN:
1573-0778
Keywords:
apoptosis
;
cell cycle
;
E1B-19K
;
hydroxyurea
;
hyperosmosis
;
hypertonic
;
monoclonal antibodies
;
OptiMAbTM
;
thymidine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract Lymphoid cells expressing sufficient levels of Bcl-2 or E1B-19K are known to resist to induction of apoptosis in glutamine-free or nutrient-limited batch cultures. However, despite the increased viability and prolonged stationary phase achieved in batch culture, product yields are not necessarily improved. Here we have found that expression of E1B-19K in NS/0 myeloma cells cultivated in the presence of certain cell cycle modulators could result in a significant increase in MAb productivity as compared to untransfected control cells. The use of E1B-19K significantly enhanced cell survival in the presence of osmolytes (sorbitol, NaCl), DNA synthesis inhibitors (hydroxyurea, excess thymidine), and the cell culture additive OptiMAb™. E1B-19K myelomas cultivated in the presence of NaCl or OptiMAb™ accumulated in the G1 phase, while those arrested with excess thymidine were blocked in all phases. Interestingly, control NS/0 cells treated with these agents were found to die in a cell-cycle specific manner. Thus, while all G1 and most S phase cells quickly underwent apoptosis, G2/M cells remained alive and maintained MAb secretion for more than 10 days if supplied with adequate nutrients. For both control and E1B-19K cells, incubation with sorbitol or hydroxyurea was detrimental for MAb secretion, while addition of NaCl, excess thymidine and OptiMAb™ resulted in an increased specific MAb productivity as compared to the batch culture. However, this increase resulted in an improvement of final MAb yields only in the case of OptiMAb™. The extension of viability conferred by E1B-19K allowed to further improve the final MAb yield obtained using OptiMAb™ with a 3.3-fold increase for E1B-19K cells as compared to 1.8-fold for control NS/0 cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008054403470
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