VSIG4 Antibody (528903) [Unconjugated]

Western blot shows lysates of HEK293T human embryonic kidney cell line either mock transfected or transfected with human VSIG4. PVDF membrane was probed with 2 µg/mL of Mouse Anti-Human VSIG4 Monoclonal Antibody (Catalog # MAB4646) followed by HRP-conjugated Anti-Mouse IgG Secondary Antibody (HAF018). A specific band was detected for VSIG4 at approximately 75 kDa (as indicated). This experiment was conducted under reducing conditions and using Western Blot Buffer Group 1.

Human CD14+ monocytes were positively selected from PBMC (MAGH105) and cultured for 7 days with 10% Human AB serum, 50 ng/ml M-CSF (216-MC), and 10μM hydrocortisone (4093). Cells were harvested and stained with either (A) Mouse anti-Human VSIG4 (Catalog # MAB4646) or (B) Isotype control antibody (MAB003) followed by Allophycocyanin-conjugated anti-Mouse IgG Secondary Antibody (F0101B) and Mouse anti-Human CD11b Alexa Fluor® 488-conjugated Monoclonal Antibody (FAB16991G). Staining was performed using our Staining Membrane-Associated Proteins protocol.

• Reactivity: Hu
• Applications: WB, Flow, CyTOF-ready
• Clone: 528903
• Clonality: Monoclonal
• Host: Mouse
• Conjugate: Unconjugated

VSIG4 Antibody (528903) [Unconjugated] Summary

• Immunogen: Mouse myeloma cell line NS0-derived human VSIG4 protein
  Arg20-Pro283
  Accession # Q9Y279
• Specificity: Detects human VSIG4 in direct ELISAs.
• Source: N/A
• Isotype: IgG2a
• Clonality: Monoclonal
• Host: Mouse
• Purity Statement: Protein A or G purified from hybridoma culture supernatant

Applications/Dilutions

• Dilutions:
  • CyTOF-ready
  • Flow Cytometry 0.25 ug/10^6 cells
  • Western Blot 2 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 VSIG4 Antibody (528903) [Unconjugated]

• CRIg
• Ig superfamily protein
• Protein Z39Ig
• V-set and immunoglobulin domain containing 4
• V-set and immunoglobulin domain-containing protein 4
• VSIG4
• Z39IG
• Z39IGcomplement receptor of the immunoglobulin superfamily

Background

VSIG4 (Vset and immunoglobulin domain containing 4), also known as complement receptor immunoglobulin (CRIg) and Z39IG, is a 45 kDa, type I transmembrane protein of the B7 family within the Ig superfamily that is expressed only in tissue resident macrophages (1-4). The gene is located on the X chromosome (2). The human VSIG4 cDNA encodes 399 amino acids (aa) including a 19 aa signal sequence, a 264 aa extracellular domain (ECD) containing a V-type and a C2-type Ig domain, a 21 aa transmembrane domain and a 95 aa cytoplasmic domain (3). The human VSIG4 ECD shares 84% aa identity with canine VSIG4. Within the IgV domain, it shares 90%, 80% and 78% aa identity with bovine, mouse and rat VSIG4, respectively; these animals lack the C2-type domain. Splice isoforms of 321, 305, 272, 201 and 199 aa lack all or part of the cytoplasmic domain, the C2-type Ig domain and/or the transmembrane domain (5). VSIG4 is specifically expressed on macrophages in the thymic medulla, peritoneum, alveoli, synovia, adipose and heart, liver Kupffer cells, placental Hofbauer cells, and atherosclerotic foam cells (1-4, 6-9). It is absent on infiltrating macrophages (8). VSIG4 is a complement receptor that binds C3b and iC3b fragments, internalizes them to recycling endosomes, and is recycled to the cell surface (4, 6). It contributes significantly to innate immunity by binding and phagocytosis of complement opsonized invading pathogens (4, 8, 10). Binding of either native or recombinant soluble VSIG4 to C3b inhibits complement amplification through the alternative, but not classical, pathway (10, 11). VSIG4 is also a negative regulator of mouse and human T cell activation (2). Although VSIG4 engagement may activate NF kappa B and thus be proinflammatory in some cases, many of its activities are important in resolving, rather than initiating, inflammation (1, 2, 7, 10, 11). There is emerging evidence in human conditions that VSIG4 may be a valuable biomarker in infection and immunity, inflammatory conditions and cancer prognosis (12, 13, 14).

1. He, J.Q. et al. (2008) Mol. Immunol. 4041.
2. Vogt, L. et al. (2006) J. Clin. Invest. 116:2817.
3. Langnaese, K. et al. (2000) Biochim. Biophys. Acta 1492:522.
4. Helmy, K. et al. (2006) Cell 124:915.
5. Entrez protein Accession # EAX05393, NP_001093901, CAI42052, CAI4205, EAX05394.
6. Tanaka, M. et al. (2008) Clin. Exp. Immunol. 154:38.
7. Lee, M.Y. et al. (2006) J. Leukoc. Biol. 80:922.
8. Gorgani, N.N. et al. (2008) J. Immunol. 181:7902.
9. Walker, M.G. (2002) Biochim. Biophys. Acta 1574:387.
10. Wiesmann, C. et al. (2006) Nature 444:217.
11. Katschke, K.J. et al. (2007) J. Exp. Med. 204:1319.
12. Small, A.G. et al. (2016) Swiss Med Wkly. 5:146.
13. Roh J. et al. (2017) Oncotarget. 8:58122.
14. Kim K.H. et al. (2016) Autophagy. 12:1647.

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.

Bioinformatics

• Uniprot:
  • Q9Y279()