Generation of Novel Anti-MUC1 Monoclonal Antibodies with Designed Carbohydrate Specificities Using MUC1 Glycopeptide Library.

Numerous anti-mucin 1 (anti-MUC1) antibodies that recognize -glycan core structures have already been developed. However, most of them show low specificities toward -glycan structures and/or low affinity toward a monovalent epitope. In this study, using an MUC1 glycopeptide library, we established two novel anti-MUC1 monoclonal antibodies (1B2 and 12D10) with designed carbohydrate specificities. Compared with previously reported anti-MUC1 antibodies, 1B2 and 12D10 showed quite different features regarding their specificities, affinities, and reactivity profiles to various cell lines. Both antibodies recognized specific -glycan structures at the PDT*R motif (the asterisk represents an -glycosylation site). 1B2 recognized -glycans with an unsubstituted -6 position of the GalNAc residue (Tn, T, and 23ST), whereas 12D10 recognized Neu5Ac at the same position (STn, 26ST, and dST). Neither of them bound to glycopeptides with core 2 -glycans that have GlcNAc at the -6 position of the GalNAc residue. Furthermore, 1B2 and 12D10 showed a strong binding to not only native MUC1 but also 20-mer glycopeptide with a monovalent epitope. These anti-MUC1 antibodies should thus become powerful tools for biological studies on MUC1 -glycan structures. Furthermore, the strategy of using glycopeptide libraries should enable the development of novel antibodies with predesigned -glycan specificities.