Siglec-2/CD22 Antibody (L007.2.5H) [Unconjugated]

Siglec‑2/CD22 was detected in immersion fixed human peripheral blood mononuclear cells (PBMCs) using Llama Anti-Human Siglec‑2/CD22 LlaMABodyTM Bivalent VHH HuIgG2 Fusion Monoclonal Antibody (Catalog # LMAB107321) at 8 µg/mL for 3 hours at room temperature. Cells were stained using Anti-alpaca Alexa Fluor 594 (red) and counterstained with DAPI (blue). Specific staining was localized to cytoplasm. Staining was performed using our protocol for Fluorescent ICC Staining of Non-adherent Cells.

Siglec‑2/CD22 was detected in immersion fixed paraffin-embedded sections of Human Tonsil using Llama Anti-Human Siglec‑2/CD22 LlaMABodyTM Bivalent VHH HuIgG2 Fusion Monoclonal Antibody (Catalog # LMAB107321) at 15 µg/mL overnight at 4 °C. Tissue was stained using anti-Llama secondaries with HRP and counterstained with hematoxylin (blue). Specific staining was localized to cytoplasm in lymphocytes. View our protocol for IHC Staining with VisUCyte HRP Polymer Detection Reagents.

• Reactivity: Hu
• Applications: IHC, ICC/IF
• Clone: L007.2.5H
• Clonality: Monoclonal
• Host: Llama
• Conjugate: Unconjugated

Siglec-2/CD22 Antibody (L007.2.5H) [Unconjugated] Summary

• Additional Information: Recombinant Monoclonal Antibody. Bivalent Llama VHH domain, Human IgG2 Fusion Antibody.
• Immunogen: Chinese Hamster Ovary cell line CHO-derived human Siglec-2/CD22 as immunogen for bivalent Llama VHH-Human IgG₂ Fusion Antibody
  Asp20-Arg687
  Accession # CAA42006.1
• Specificity: Clone L007.2.5H is a bivalent Llama VHH-Human IgG₂ Fusion Antibody that detects Siglec-2/CD22 in direct ELISAs. Antibody construct is depicted below.

  Human Siglec-2/CD22 Specific Llama VHH domain	Llama Hinge	Human IgG2
  N-terminus		C-terminus

• Source: N/A
• Clonality: Monoclonal
• Host: Llama
• Purity Statement: Protein A or G purified from cell culture supernatant

Applications/Dilutions

• Dilutions:
  • Immunocytochemistry 8-25 ug/mL
  • Immunohistochemistry 8-25 ug/mL

Packaging, Storage & Formulations

• Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -20 to -70 °C as supplied.
  • 1 month, 2 to 8 °C under sterile conditions after reconstitution.
  • 6 months, -20 to -70 °C under sterile conditions after reconstitution.
• Buffer: Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied either lyophilized or as a 0.2 µm filtered solution in PBS.
• Reconstitution Instructions: Reconstitute at 0.5 mg/mL in sterile PBS.

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Siglec-2/CD22 Antibody (L007.2.5H) [Unconjugated]

• B-cell receptor CD22
• BL-CAM
• B-lymphocyte cell adhesion molecule
• CD22 antigenMGC130020
• CD22 molecule
• CD22
• sialic acid binding Ig-like lectin 2
• Sialic acid-binding Ig-like lectin 2
• Siglec2
• Siglec-2
• SIGLEC2FLJ22814
• T-cell surface antigen Leu-14

Background

Siglecs are type I transmembrane proteins that belong to the immunoglobulin (Ig) superfamily and function as mammalian lectins (1). They are characterized by an extracellular domain consisting of various numbers of Ig domains with a conserved N-terminal V-set Ig ligand-binding domain. This binds species-specific sialic acid motifs on protein and lipid scaffolds to regulate intracellular signaling pathways (2). The cytoplasmic tail has signaling motifs, in most cases immunoreceptor tyrosine-based inhibitory motif (ITIM) (3). Human Siglec-2, also known as B cell antigen CD22 or B lymphocyte cell adhesion molecule (BL-CAM), is a B cell restricted glycoprotein that is expressed in the cytoplasm of progenitor B and pre B cells and on the surface of mature B cells. Two distinct human Siglec-2/CD22 cDNAs that arise from differential RNA processing of the same gene have been isolated. The predominant Siglec-2/CD22 beta encodes an 847 amino acid (aa) polypeptide with a hydrophobic signal peptide, an N-terminal Ig-like V type domain, six Ig-like C2 type domains, a transmembrane region and a cytoplasmic tail with 4 immunoreceptor tyrosine-based inhibition motifs (ITIMs) (4). The variant Siglec-2/CD22 alpha encodes a 647 aa polypeptide missing two Ig-like C2 type domains and has a truncated (23 aa) cytoplasmic tail (5). Mature human Siglec-2 beta consists of a 668 amino acid (aa) extracellular domain (ECD), a 19 aa transmembrane segment, and a 141 aa cytoplasmic domain. Within the ECD, human Siglec-2 shares 59% and 58% aa sequence identity with the mouse and rat Siglec-2, respectively. Siglec-2/CD22 is an adhesion molecule that preferentially binds alpha 2,6- linked sialic acid on the same (cis) or adjacent (trans) cells. Interaction of CD22 with trans ligands on opposing cells was found to be favored over the binding of ligands in cis (6). Besides its role as an adhesion molecule, Siglec-2/CD22 is a coreceptor that physically interacts with B-cell receptor (BCR) and is rapidly phosphorylated upon BCR ligation. It negatively regulates BCR signals by recruiting tyrosine phosphatase SHP-1 to its ITIMs. Phosphorylated Siglec-2/CD22 can also interact with other intracellular effector proteins such as Syk, PLC gamma, PI3 kinase and Grb-2, suggesting it may play a role in positive signaling (7-9). Another function of CD22 is that it mediates the anti-phagocytic effect of alpha 2,6-linked sialic acid, and inhibition of CD22 promotes the clearance of myelin debris, amyloid-beta oligomers and alpha -synuclein fibrils in vivo(10). CD22 also plays a role in autoimmunity and has great potential for CD22-based immunotherapeutics for the treatment of autoimmune diseases such as systemic lupus erythematosus (SLE) (11).

1. Crocker, P.R. et al. (2007) Nat. Rev. Immunol. 7:255.
2. Poe, J.C. and T.F. Tedder (2012) Trends Immunol. 33:413.
3. Meyer, S.J. et al. (2018) Front. Immunol. 9:2820.
4. Wilson, G.L et al. (1991) J. Exp. Med. 173:137.
5. Stamenkovic, I. and B. Seed (1990) Nature 345:74.
6. Collins, B.E. et al. (2004) Proc. Natl. Acad. Sci. 101:6104.
7. Crocker, P.R. and A. Varki (2001) Immunology 103:137.
8. Ravetch, J.V. and L.L. Lanier (2000) Science 290:84.
9. Wienands, Y.J. et al. (1999) J. Biol. Chem. 274:18769.
10. Pluvinage, J.V. et al. (2019) Nature. 5568:7751.
11. Clark, E.A. et al. (2018) Front. Immunol. 9:2235.

Limitations

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Primary Antibodies are guaranteed for 1 year from date of receipt.

FAQs for Siglec-2/CD22 Antibody (LMAB107321). (Showing 1 - 1 of 1 FAQ).

1. I am interested in buying a CD22 antibody for fluorescence microscopy and FACS I red on your web page that you also offer to label your antibodies, if required, is that correct?
   • We do have the ability to perform custom conjugations on certain antibodies, including some to the CD22 protein. If you send me the conjugate you are interested in I can provide you with a quote.

Bioinformatics

• Uniprot:
  • CAA42006.1()