Monoclonal 11B3 anti-TNT (trinitrotoluene) antibody was expressed as a monovalent and bivalent form using different prokaryotic and eukaryotic expression systems. Recombinant expression in Escherichia coli, mammalian cells and the methylotrophic yeast Pichia pastoris was performed to obtain disulfide-linked and glycosylated antibody forms. The generation of antibody and subsequent evaluation of the expression rates were performed using intracellular, excretory and periplasmatic expression techniques. All methods involved striving for native expressed antibody with maintenance of its functionality only.