CELL-CULTURE CONDITIONS DETERMINE THE ENHANCEMENT OF SPECIFIC MONOCLONAL-ANTIBODY PRODUCTIVITY OF CALCIUM ALGINATE-ENTRAPPED S3H5/GAMMA-2BA2 HYBRIDOMA CELLS

Immobilization offers several intrinsic advantages over free suspension cultures for the production of monoclonal antibodies. An important advantage of immobilization is the improved specific monoclonal antibody (MAb) productivity (q(MAb)) that can be obtained. However, there are conflicting reports in the literature on the enhancement of the q(MAb) with immobilization. The discrepancies between these reports can be attributed to either the cultivation methods used for immobilized cells or to difference between the cell lines used in the various studies. We show that these differences may be attributed to the different cultivation methods used for one model hybridoma cell line. S3H5/gamma2bA2 hybridoma cells entrapped in different sizes of calcium alginate beads were cultivated in both T- and spinner flasks in order to determine whether cultivation methods (T- and spinner flasks) and bead size influence the q(MAb). Free-suspended cell cultures inoculated with cells recovered from alginate beads were also carried out in order to determine whether changes in the q(MAb) of the entrapped cells are reversible. The cultivation method was found to influence significantly the q(MAb) of the entrapped cells. When the entrapped cells in 1-mm diameter beads were cultivated in T-flasks, the q(MAb) was not increased by 200% as previously observed in an entrapped cell culture using 1-mm-diameter alginate beads in spinner flasks. The q(MAb) of the entrapped cells was approximately 58% higher than that of the free-suspended cells in a control experiment. Unlike the cultivation method, the bead size in the range of 1- to 3-mm diameter did not significantly influence the q(MAb), regardless of cultivation methods. The changes in q(MAb) of the entrapped cells were reversible. When the free-suspended cells recovered from the beads in T- and spinner flasks were sub-cultured in T- and spinner flasks, respectively, the enhanced q(MAb) of the entrapped cells in both cases decreased to the level of the free-suspended cells in a control experiment. Taken together, these results show that the method of cultivation of hybridoma cells immobilized in alginate beads determines the extent of enhancement of the q(MAb).