Siglecs: targets for immune regulation and cancer therapy

sialic acid-binding immunoglobulin-type lectins

Siglecs (sialic acid-binding immunoglobulin-type lectins) are receptors predominantly located on the surface of hematopoietic cells. Recent publications highlight the important roles Siglecs play in tumor immunosurveillance making them attractive anti-cancer drug targets. Inhibitory receptors Siglec-7 and Siglec-9 are expressed on NK cells and recognize tumor-associated sialosides (1,2). Also, Siglec-15 (Catalog # 9227-SL) was identified as an immune suppressor by engaging an unknown receptor on T cells. Similar to PD-L1/PD-1 immune checkpoint blockade, Siglec-15 may be a potential target for cancer immunotherapy (3).

Siglecs interact with an array of linkage-specific sialic acids on a glycan structure expressed on host cells, as well as pathogens. So far, there are 15 different human and 9 murine Siglecs. Each type of Siglec generally recognizes a particular set of sialylated glycan containing differently linked sialic acid molecules (4,5). On the cytoplasmic side, most Siglecs have immune receptor tyrosine-based inhibition motifs (ITIM), which initiate signaling cascades resulting in downregulation of proinflammatory responses.

R&D Systems provides you with the widest selection of high-quality, bioactive Siglecs on the market. Can’t find what you are looking for? The R&D Systems Custom Protein Development Team can work with you to create a customized protein solution to meet your specific research needs.

Protein Species Source Tag Catalog # Activity
Siglec-1/CD169 Human NS0 His A5197-SL Supports RBC adhesion
Mouse NS0 Fc 5610-SL
Siglec-2/CD22 Human NS0 Fc 1968-SL Supports RBC adhesion
Mouse NS0 Fc 2296-SL
Cyno HEK293 His 9864-SL
Cyno HEK293 Fc 10031-SL
Siglec-3/CD33 Human NS0 Fc 1137-SL Supports RBC adhesion
Siglec-4a/MAG Human HEK293 Fc 8940-MG Inhibits neurite outgrowth of E13 chick embryonic DRG neurons
Mouse NS0 Fc 8580-MG
Rat NS0 Fc 538-MG
Siglec-5/CD170 Human NS0 Fc 1072-SL Supports RBC adhesion
Siglec-6/CD327 Human CHO Fc 2859-SL Binds biotinylated Neu5Ac alpha 2-6GalNAc alpha
Siglec-7/CD328 Human NS0 Fc 1138-SL Supports RBC adhesion
Siglec-8 Human NS0 Fc 9045-SL Binds biotinylated Sialyl Lewis X
Siglec-9 Human NS0 Fc 1139-SL Supports RBC adhesion
Siglec-10 Human NS0 Fc 2130-SL Binds biotinylated 6’-Sialyllactose-Polyacrylamide
Siglec-11 Human CHO Fc 3258-SL Binds biotinylated (Neu5Aca2-8)2-Polyacrylamide
Siglec-14 Human NS0 Fc 4905-SL Supports RBC adhesion
Siglec-15 Human CHO Fc 9227-SL Inhibits anti-CD3 induced IFN-gamma secretion by T cells
Siglec-E Mouse NS0 Fc 5806-SL Binds biotinylated Neu5Ac alpha 2-6GalNAc alpha -Polyacrylamide
Siglec-F Mouse NS0 Fc 1706-SF Supports RBC adhesion
Mouse NS0 His 10171-SF New!
Siglec-G Mouse NS0 Fc 10103-SL New! Binds biotinylated 6'-Sialylactose-PAA
Recombinant Cynomolgus Monkey Siglec 2/CD22 Fc Chimera Protein
View Larger Image
Recombinant Human Siglec-15 Fc Chimera protein
View Larger Image
Recombinant Mouse Siglec F His-tag protein
View Larger Image
Recombinant Cynomolgus Monkey Siglec‑2/CD22 Fc Chimera (Catalog # 10031-SL) supports the adhesion of human red blood cells. The ED50 for this effect is 0.07-0.42 ug/mL. Recombinant Human Siglec-15 Fc Chimera (Catalog # 9227-SL) inhibits anti-CD3 antibody induced IFN-gamma secretion by human T cells. The ED50 for this effect is 1-10 μg/mL. 2 μg/lane of Recombinant Mouse Siglec‑F His-tag (Catalog # 10171-SF)was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 59-68 kDa.


1. Jandus, C. et al. (2014) J. Clin. Investig. 124:1810.

2. Stanczak, M.A. et al. (2018) J. Clin. Investig. 128:4912.

3. Wang, J. et al. (2019) Nat. Med. 25:656.

4. Bornhöfft, K.F. et al. (2018) Dev. Comp. Immunol. 86:219.

5. Zhou, J.Y. et al. (2018) Trends Immunol. 39:523.

View other Immune-checkpoint blockade targets

  • B7/CD28 Family

    Some of the most targeted checkpoint proteins

  • Butyrophilins

    Products for Butyrophilin-related Research

  • AMIGOs

    New Data: AMIGOs as T Cell Suppressors

  • LILRA/B Receptors

    Checkpoint Targets with Novel Ligands

  • VSIG

    IgG Superfamily Members: Data Supports Their Potential as Immunotherapeutic Drug Targets

  • VSTM

    New B7-like immune checkpoint targets


    Adhesion Molecules as Novel Targets for Cancer Therapies

  • SIRPs

    Paired receptors with either activating or inhibitory signals.

Related Pathways

T Cell Co-Signaling Pathway: Ligand-Receptor Interactions

Mechanisms of Regulatory T Cell-Mediated Suppression

Other immune-checkpoint blockade resources:

All proteins from R&D Systems