N-linked glycan structures of a mouse monoclonal antibody produced from tobacco BY2 suspension-cultured cells

cDNA encoding H- and L-chains from a mouse monoclonal antibody was introduced into tobacco BY2 cells, and the resulting sugar chain structures of plant-produced antibodies were analyzed by a combination of HPLC, exoglucosidase digestion and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The glycan structures determined were Man5–6GlcNAc2 (22.3%), GlcNAcMan5GlcNAc2 (3.1%), GlcNAcMan3FucXylGlcNAc2 (24.4%), GlcNAcMan3XylGlcNAc2 (17.8%), Man3FucXylGlcNAc2 (24.3%), and Man3XylGlcNAc2 (8.1%). The major glycan structures of the antibodies produced by transgenic suspension-cultured cells contain typical plant bisecting β(1 and 2)-xylose and α(1 and 3)-fucose residues, suggesting the posttranslational modification of a recombinant antibody in the late Golgi apparatus.