Program

Poster Presentations

Day 4, May 18（Fri.）　　Poster

4P-31　　PDF

Glycan Isomeric Analysis of Therapeutic Antibodies by LC-ESI-MS/MS Technique

(Noguchi Inst.)
^oMasaki Kurogochi, Kenji Osumi, Shou Takashima, Wataru Tsukimura, Masako Mori, Junko Amano, Mamoru Mizuno, Akio Matsuda

Many therapeutic IgG antibodies have been developed in various cell expression systems. Their N-glycosylation patterns differ during various processes or among cell expression systems. The N-glycan can modulate the effector functions of IgG antibodies, such as antibody-dependent cellular cytotoxicity etc. To ensure the N-glycan quality, the commonly used methods for glycan analysis are divided into four protocols (analysis of intact glycoproteins, glycopeptides, released glycans, and monosaccharides). We have already prepared the homogeneous glycosylated monoclonal antibodies by means of chemoenzymatic approach, and obtained the glycoengineered monoclonal antibodies having different glycan isomer with the same molecular weight (e. g. G1aF and G1bF) 1, 2). Then, we performed reverse phase LC-MS analysis of N-glycopeptides after tryptic digestion and determined the quantitative and qualititative value of glycopeptides. Although each N-glycopeptides with different glycan isomer have the same LC-elution time and MS spectrum due to the similarity of their characteristics, their fragment ion on MS/MS measurement are a little different owing to the branching structure. Thus, we found that the glycan isomeric ratio could be determined by calculating the value of their fragment ion, and measured the glycan isomeric ratio of the mixtures on therapeutic antibodies.