A comparison of intensive cell culture bioreactors operating with hybridomas modified for inhibited apoptotic response.

It is demonstrated, using two different perfusion reaction systems, that hybridoma modified by inhibiting their apoptotic response can give improved process performance in terms of cell number and viability in intensive cell culture. Two cell perfusion systems, one using a spin filter and the other an ultrasonic filter, are compared using two cell lines. One cell line is transfected with the bcl-2 gene (TB/C3 bcl-2) which encodes the 'anti-apoptotic' human bcl-2 protein and the other cell line (TB/C3 pEF) with a negative transfection vector. Both reactor systems give similar retention performance for both cell lines. Bcl-2 transfected cells reach higher cell densities than the control cell line, and the percentage of apoptotic cells is clearly lower than with pEF cells. The maximum cell numbers of the bcl-2 cell line are 1.21 x 10(7) ml-1 in the ultrasonic filter culture and 1.58 x 10(7) ml-1 in the spin filter culture, respectively. Using the pEF cell line the maximum cell number reaches 6.0 x 10(6) ml-1 with ultrasonic retention and 5.9 x 10(6) ml-1 in the spin filter. The use of ultrasound in this cell retention system has no apparent influence on cell growth, productivity or viability. Selective retention of viable cells is detectable but the effect of removing non-viable cells is negligible.