Evaluation of rhIFN-beta production by CHO cells under different culture conditions

ROMINA ZUQUELI; MATÍAS DEPETRIS; FEDERICO MILANO; NORMA PEROTTI; NATALIA CEAGLIO; MARCOS OGGERO; MARINA ETCHEVERRIGARAY; RICARDO KRATJE

San Carlos de Bariloche. Pcia. de Río Negro. Argentina

Congreso; XXXIX Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB) – Simposio Internacional de Proteínas; 2003

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Human beta interferon (hIFN-beta) is indicated for the treatment of multiple sclerosis. The recombinant protein is produced either in mammalian cells (IFn-beta-1a) or in E. coli (IFN-beta-1b). IFN-beta-1a is a glycoprotein structurally indistinguishable from the natural one, whereas IFN-beta-1b lacks the carbohydrated chain. As a result differences have been found in their specific biological activities and in the plasmatic clearance rate. Minor doses of IFN-beta-1a are required diminishing the immunologic compromise in patients. To express hIFN-beta in mammalian cells, an expression vector was constructed cloning the human gene into the plasmid pCI-neo. Several transfections of CHO cells were performed using LipofectAMINE 2000 and pCI-neo-rhINF-beta. Three positive clones were selected (2A5 1D7, 2A5 1D5 and 2A6 1G5). With the aim of improving cell productivity, different culture conditions were assayed by changing the amounts of fetal calf serum (FCS) and sodium butyrate. We found a higher production of rhIFN-beta by CHO cells cultured in the presence of 0.1% (v/v) FCS and 5 mM sodium butyrate. To determine the biological activity of the supernatants, we developed a rapid cytophatic effect inhibition biossay which could be completed in 24 h, with a detection limit of 0.75 UI/ml.