A versatile soluble siglec scaffold for sensitive and quantitative detection of glycan ligands

Nat Commun. 2020 Oct 9;11(1):5091. doi: 10.1038/s41467-020-18907-6.


Sialic acid-binding immunoglobulin-type lectins (Siglecs) are immunomodulatory receptors that are regulated by their glycan ligands. The connections between Siglecs and human disease motivate improved methods to detect Siglec ligands. Here, we describe a new versatile set of Siglec-Fc proteins for glycan ligand detection. Enhanced sensitivity and selectivity are enabled through multimerization and avoiding Fc receptors, respectively. Using these Siglec-Fc proteins, Siglec ligands are systematically profiled on healthy and cancerous cells and tissues, revealing many unique patterns. Additional features enable the production of small, homogenous Siglec fragments and development of a quantitative ligand-binding mass spectrometry assay. Using this assay, the ligand specificities of several Siglecs are clarified. For CD33 (Siglec-3), we demonstrate that it recognizes both α2-3 and α2-6 sialosides in solution and on cells, which has implications for its link to Alzheimer's disease susceptibility. These soluble Siglecs reveal the abundance of their glycan ligands on host cells as self-associated molecular patterns.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD / genetics
  • Antigens, CD / metabolism
  • Breast Neoplasms / metabolism
  • CHO Cells
  • Cricetulus
  • Female
  • HEK293 Cells
  • Humans
  • Immunoglobulin Fc Fragments / genetics
  • Immunoglobulin Fc Fragments / metabolism
  • Immunoglobulin G / genetics
  • Immunoglobulin G / metabolism
  • K562 Cells
  • Mass Spectrometry
  • Polysaccharides / analysis*
  • Polysaccharides / metabolism
  • Sialic Acid Binding Ig-like Lectin 3 / metabolism
  • Sialic Acid Binding Immunoglobulin-like Lectins / chemistry*
  • Sialic Acid Binding Immunoglobulin-like Lectins / genetics
  • Sialic Acid Binding Immunoglobulin-like Lectins / isolation & purification
  • Sialic Acid Binding Immunoglobulin-like Lectins / metabolism*
  • Sialic Acids / metabolism
  • Sialyltransferases / genetics
  • Sialyltransferases / metabolism
  • Spleen / cytology
  • Spleen / metabolism
  • Streptavidin / metabolism


  • Antigens, CD
  • CD33 protein, human
  • Immunoglobulin Fc Fragments
  • Immunoglobulin G
  • Polysaccharides
  • Sialic Acid Binding Ig-like Lectin 3
  • Sialic Acid Binding Immunoglobulin-like Lectins
  • Sialic Acids
  • Streptavidin
  • Sialyltransferases
  • ST6GAL1 protein, human