2 research outputs found
Convergent Solid-Phase Synthesis of Macromolecular MUC1 Models Truly Mimicking Serum Glycoprotein Biomarkers of Interstitial Lung Diseases
Synthetic macromolecular MUC1 glycopeptides
have been used to unravel molecular mechanisms in antibody recognition
of disease-specific epitopes. We have established a novel synthetic
strategy for MUC1 tandem repeats having complex O-glycosylation states
at each repeating unit based on convergent solid-phase fragment condensation
under microwave irradiation. We have accomplished the synthesis of
77 amino acid MUC1 glycopeptides (MW = 12 759) having three
major antigenic O-glycoforms [Tn, core 1 (T), and core 2 structures]
at 10 designated positions out of 19 potential O-glycosylation sites.
We demonstrate that the macromolecular MUC1 glycopeptide displaying
the essential glycopeptidic neoepitope Pro-Asp-ThrÂ(sialyl-T)-Arg-Pro-Ala-Pro
at two different tandem repeats is an excellent serum MUC1 model showing
ideal stoichiometric binding with anti-KL6/MUC1 antibody in the sandwich
ELISA to quantify human serum KL6/MUC1 levels as a critical biomarker
of interstitial lung diseases
Generation of Novel Anti-MUC1 Monoclonal Antibodies with Designed Carbohydrate Specificities Using MUC1 Glycopeptide Library
Numerous
anti-mucin 1 (anti-MUC1) antibodies that recognize <i>O</i>-glycan core structures have already been developed. However,
most of them show low specificities toward <i>O</i>-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 <i>O</i>-glycan structures at the PDT*R
motif (the asterisk represents an <i>O</i>-glycosylation
site). 1B2 recognized <i>O</i>-glycans with an unsubstituted <i>O</i>-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 <i>O</i>-glycans that have GlcNAc at the <i>O</i>-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 <i>O</i>-glycan structures.
Furthermore, the strategy of using glycopeptide libraries should enable
the development of novel antibodies with predesigned <i>O</i>-glycan specificities