EFFECTS OF CULTURE CONDITIONS ON THE PRODUCTION AND QUALITY OF MONOCLONAL IGA

Monoclonal IgA antibodies have been produced by a hybridoma cell line grown in different bioreactors using serum-containing and protein-free media in both basal and fortified versions. The effects of culture co nditions on IgA production and quality have been studied using an anti alpha-chain ELISA, an antigen-specific ELISA, and anti alpha-chain We stern blotting from which the fractions of the various IgA molecular f orms were estimated by densitometry measurements. In stirred-tank reac tor (STR) batch cultures, a significant increase in final IgA concentr ation (220-720%) was obtained in both media types due to amino acid su pplementation; in protein-free media, the productivity of total IgA wa s slightly lower, but the fraction of antigen-binding IgA was larger ( 81% versus 60%). In hollow-fiber reactors, the IgA concentration was s trongly dependent on the harvesting frequency, and thus varied over a wide range (0.5-14 g l(-1)). Compared with IgA produced in STR culture s, larger fractions of polymers and aggregates were observed. The frac tion of antigen-binding IgA dropped below 40% in both media types when the total IgA concentration exceeded 1-3 g l(-1). Further characteriz ation of the various molecular forms will enable the determination of the optimum culture conditions for the production of the complete mole cule (sIgA). (C) 1997 Elsevier Science Inc.