Monoclonal IgA antibodies have been produced by a hybridoma cell line grown in different bioreactors using serum-contg. and protein-free media in both basal and fortified versions. The effects of culture conditions on IgA prodn. and quality were studied using an anti a-chain ELISA, an antigen-specific ELISA, and anti a-chain Western blotting from which the fractions of the various IgA mol. forms were estd. by densitometry measurements. In stirred-tank reactor (STR) batch cultures, a significant increase in final IgA concn. (220-720%) was obtained in both media types due to amino acid supplementation; in protein-free media, the productivity of total IgA was slightly lower, but the fraction of antigen-binding IgA was larger (81% vs. 60%). In hollow-fiber reactors, the IgA concn. was strongly dependent on the harvesting frequency, and thus varied over a wide range (0.5-14 g/L). Compared with IgA produced in STR cultures, larger fractions of polymers and aggregates were obsd. The fraction of antigen-binding IgA dropped below 40% in both media types when the total IgA concn. exceeded 1-3 g/L. Further characterization of the various mol. forms will enable the detn. of the optimum culture conditions for the prodn. of the complete mol. [on SciFinder (R)]