Further characterization of the binding properties of two monoclonal antibodies recognizing human Tn red blood cells

Albert M. Wu*, June H. Wu, Hsiang Wei Kuo, Anthony Herp

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

6 Scopus citations

Abstract

The terminal α anomeric GalNAc residue is an essential sugar for the Tn glycotope, human blood group A determinant, and Forssman antigen. In a previous study [King M.J., Parson S.F., Wu A.M., Jones N., Transfusion 31: 142-149, 1991], we defined two monoclonal antibodies (MoAbs, BRIC66 and BRIC111) reacting with human Tn red blood cells. However, more advanced studies of these two MoAbs were hampered by the lack of availability of Gal/GalNAc related glycotopes. In order to use these antibodies as powerful probes to elucidate structural changes during life processes, we have characterized in detail the combining sites of these two MoAbs using enzyme-linked immunosorbent (ELISA) and inhibition assays with an extended glycan/ligand collection. From the results, it has been established that BRIC66 demonstrated multiple specificities and its reactivity towards glycotopes was defined as: GalNAcα1→Ser/Thr (Tn) ≥ GalNAcα1→3(LFucα1→2)Gal (Ah) > GalNAcα1→3Galβ1→4Glc (AL) > GalNAα1→3Gal (A) > GalNAcα1→3GalNAc (F) > GalNAc ≫ Gal or Glc. Another MoAb, BRIC111, mainly bound Tn-glycophorin. The best ligand for this MoAb was Tn-containing glycopeptides (M.W. < 3.0 × 103 Da) from asialo ovine salivary mucin (OSM), which was approximately 70 and 58 times more active than GalNAc and monomeric GalNAcα1→Ser/Thr (Tn), respectively, suggesting that the active glycotopes present in glycophorin for BRIC111 binding also exist in OSM. The N-acetyl group at carbon-2 and configuration at carbon-2 and carbon-4 of the α anomeric GalNAc are required for the binding of either MoAb. Identication of these binding properties should aid in the selection of these MoAbs and the conditions required for biological studies and clinical applications.

Original languageEnglish
Pages (from-to)153-166
Number of pages14
JournalJournal of Biomedical Science
Volume12
Issue number1
DOIs
StatePublished - 01 2005

Keywords

  • Carbohydrate specificities
  • Glycoprotein binding
  • Monoclonal antibodies
  • T glycotopes
  • Tn epitopes

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