THE INVENTION GENERALLY RELATES TO THE FIELD OF RECOMBINANT PROTEIN PRODUCTION. MORE PARTICULARLY, THE INVENTION RELATES TO THE USE OF AVIAN EMBRYONIC DERIVED STEM CELL LINES, NAMED EBx®, FOR THE PRODUCTION OF PROTEINS AND MORE SPECIFICALLY GLYCOPROTEINS SUCH AS ANTIBODIES. THE INVENTION IS USEFUL FOR THE PRODUCTION OF MONOCLONAL IgGI ANTIBODY SUBTYPE HAVING HIGH CELL-MEDIATED CYTOTOXIC ACTIVITY. THE INVENTION RELATES TO THE USE OF SUCH ANTIBODIES AS A DRUG TO TREAT CANCERS AND INFLAMMATORY DISEASES.