Physiological responses of hybridoma cells in a protein‐free medium to soluble and immobilized antigen

Abstract

This study examined the effect of antigen in a protein free medium on cell growth and monoclonal antibody production by a hybridoma line. Antigen immobilized on a Sepharose gel matrix via a bovine gamma-globulin carrier protein was used to stimulate the cell cultures in T-flasks. In comparison to antigen-free culture, total antibody production during was increased up to 40%, while slower cell growth rates were observed. The specific antibody production during the stationary culture phase was 40% to 80% higher in the presence of immobilized antigen. The surface density of antigen on the Sepharose beads had a strong influence on the physiological response of the hybridomas.

Effect of growth factors and antigen on hybridoma cell culture dynamics

“…This observation is in agreement with results previously reported (Dandulakis et al, 1994), and may be partially due to a programmed cell death pathway (apoptosis) induced by a cell-surface antibody crosslinking via the immobilized antigen (Scott, 1993). We also observe that all three growth factors show similar positive effects on cell growth kinetics.…”

“…The beads had 16 mol of Ag/mol carrier protein and 10 mg carrier protein/mL bead. The culture with no growth factors present showed an increase of total antibody produced relative to the antigen-free, factor-free culture by 10%; this is in agreement with previous reports (Dandulakis et al, 1994). The cultures with EGF and FGF showed an increase of 40%, and the culture with IL-2 an increase of 30%, relative to the antigen-free, growth factorfree culture.…”

“…The highest antibody production was achieved when immobilized antigen at low concentrations was also present, in agreement with our previous results in the absence of growth factors (Dandulakis et al, 1994). When the amount of immobilized antigen increased the total antibody production decreased.…”

“…Under these conditions we could observe not only permanent changes that the antigen stimulation could possibly bring on the hybridoma cells, but also transient and growth-phase-specific changes, which could be exploited for improving the performance of a bioreactor. We have previously reported that the continuous presence of immobilized antigen in a protein-free medium hybridoma culture can significantly increase the specific antibody production (Dandulakis et al, 1994). In the present study, we investigated the cell growth and antibody production kinetics when growth factors are present in the absence or continuous presence of free, antibody-unbound antigen in the culture broth.…”

“…This physiology poses many challenges to the bioreactor design and to the overall bioprocess development (Harbour et al, 1988). Several medium requirements and refinements have been reported (Dandulakis et al, 1994). Particular attention has been given to the development of media that require little or no serum addition, because serum is an expensive and highly variable complex ingredient of direct animal provenance.…”