Summary of human Siglec receptors, their expression on the surface of different cells, their intracellular signaling and their binding to sialic acid-containing glycan ligands
| Siglec | Expression | Function | Binding specificity |
| Siglec-1, sialoadhesin | Macrophages, monocytes | No intracellular ITIM or ITIM-like motifs, supports phagocytosis | α2,3>α2,6 |
| Siglec-2, CD22 | B cells | Inhibitory Siglec, inhibitory B cell receptor | α2,6 |
| Siglec-3, CD33 | Myeloid cells (including neutrophils, monoytes and progenitors) | Inhibitory Siglec (ITIM, ITIM-like) | α2,6>α2,3 |
| Siglec-4, myelin-associated glycoprotein | Myelin producing cells | No intracellular ITIM or ITIM-like motifs, important for | α2,3>α2,6 |
| Siglec-5 | Monocytes, macrophages, neutrophils, activated T cells | Inhibitory Siglec (ITIM, ITIM-like), paired receptor with Siglec-14 | α2,3 |
| Siglec-6 | Trophoblast, chronic lymphocytic leukemia cells | Inhibitory Siglec (ITIM, ITIM-like) | α2,6 |
| Siglec-7 | NK cells, intratumoral T cells | Inhibitory Siglec (ITIM, ITIM-like) | α2,8>α2,6>α2,3 |
| Siglec-8 | Eosinophils | Inhibitory Siglec (ITIM, ITIM-like) | α2,3>α2,6 |
| Siglec-9 | Myeloid cells, NK cells, intratumoral T cells, dendritic cells | Inhibitory Siglec (ITIM, ITIM-like) | α2,3=α2,6, broadly binding, also binding to some protein ligand |
| Siglec-10 | B cells, T cells | Inhibitory Siglec (ITIM, ITIM-like) | α2,3=α2,6 |
| Siglec-11 | Macrophages, microglia | Inhibitory Siglec (ITIM, ITIM-like), paired receptor wit | α2,8 |
| Siglec-XII | Epithelial cells, cancer cells | No binding to sialic acid-containing ligands (mutation of essential arginine in carbohydrate-recognition | No binding to sialic acid ligands |
| Siglec-14 | Monocytes, macrophages, neutrophils | Activating Siglec, positively charged amino acid mediates binding to DAP12, paired receptor with Siglec-5 | α2,3 similar binding as its paired receptor Siglec-5 |
| Siglec-15 | Macrophages, dendritic cells, osetoclasts | Activating Siglec, positively charged amino acid mediates binding to DAP12 | α2,6 |
| Siglec-16 | Macrophages, microglia | Activating Siglec, positively charged amino acid mediates binding to DAP12, paired receptor with Siglec-11 | α2,8 similar binding as its paired receptor Siglec-11 |
ITIM, immunoreceptor tyrosine-based inhibitory motif.