Preparation of Recombinant Siglecs and Identification of Their Ligands

Siglecs are transmembrane receptor-like vertebrate lectins that recognize glycans containing sialic acid. Most Siglecs also interact with intracellular signal transduction molecules, and modulate immune responses. Recombinant soluble Siglecs fused with the fragment crystallizable (Fc) region of immunoglobulin G (Siglec-Fc) are a versatile tool for the investigation of Siglec functions. We describe protocols for the production of recombinant Siglec-Fc, the analysis of expression of Siglec ligands by flow cytometry, and the identification of the Siglec ligand candidates based on proximity labeling.