Recombinant Human B7-H3 (4Ig)/B7-H3b Fc Chimera Protein, CF

2 μg/lane of Recombinant Human B7-H3 (4Ig)/B7-H3b Fc Chimera Protein (10472-B3) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 100-120 kDa and 200-240 kDa, respectively.

• Reactivity: Hu
• Applications: Bioactivity
• Format: Carrier-Free

Recombinant Human B7-H3 (4Ig)/B7-H3b Fc Chimera Protein, CF Summary

• Details of Functionality: Measured by its ability to inhibit anti-CD3 antibody induced IL-2 or IFN-gamma secretion by human T cells. The ED₅₀ for this effect is 2-20 µg/mL.
• Source: Human embryonic kidney cell, HEK293-derived human B7-H3 protein
  

  Human B7-H3 (4Ig)/B7-H3b (Leu29-Thr461) Accession # NP_001019907.1	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• N-terminal Sequence: Leu29
• Structure / Form: Disulfide-linked homodimer
• Protein/Peptide Type: Recombinant Proteins
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Endotoxin Note: <0.10 EU per 1 μg of the protein by the LAL method.

Applications/Dilutions

• Dilutions:
  • Bioactivity
• Theoretical MW: 73 kDa.
  Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
• SDS-PAGE: 100-120 kDa, under reducing conditions

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.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.
• Buffer: Lyophilized from a 0.2 μm filtered solution in PBS.
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Reconstitution Instructions: Reconstitute at 200 μg/mL in PBS.

Notes

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

Alternate Names for Recombinant Human B7-H3 (4Ig)/B7-H3b Fc Chimera Protein, CF

• B7H3
• B7-H3
• B7H34Ig-B7-H3
• B7-H3B7 homolog 3
• CD276 antigen
• CD276 molecule
• CD276
• Costimulatory molecule

Background

Human B7 homolog 3 (B7-H3), also known as CD276, is a member of the B7 family of immune checkpoint molecules, responsible for regulating immune responses (1‑3). There are at least seven structurally related B7 family members, all sharing about 20-40% amino acid (aa) sequence identity (4). The B7 protein family are immunoglobulin (Ig) superfamily members with varying numbers of Ig-V-like and Ig-C-like regions in the extracellular domain (ECD) and they can either be glycosylphosphatidylinositol (GPI)-linked or transmembrane (4). The mature ECD of B7-H3 contains two V-like and two C-like Ig domains, a transmembrane region, and a short cytoplasmic domain. An isoform of human B7-H3 containing only a single set of V-like and C-like Ig domains in the ECD has also been identified (1, 5). The ECD of both mouse and rat B7-H3 only contain a single set of V-like and C-like Ig domains. Human B7-H3 is not expressed on resting B cells, T cells, monocytes or dendritic cells, but is induced on dendritic cells and monocytes by inflammatory cytokines (1, 6). B7-H3 is also overexpressed in numerous cancers including bladder, breast and melanoma (7). Unlike other B7 family members, human B7-H3 does not bind any known members of the CD28 family of immunoreceptors and its receptor has yet to be identified. However, B7-H3 has been shown to bind an unidentified counter-receptor on activated T cells to costimulate the proliferation of CD4+ or CD8+ T cells (8). B7-H3 has also been found to enhance the induction of primary cytotoxic T lymphocytes and stimulate IFN-gamma production (1-3, 8).

1. Chapoval, A.I. et al. (2001) Nat. Immunol. 2:269.
2. Sharpe, A.H. and G.J. Freeman (2002) Nat. Rev. Immunol. 2:116.
3. Coyle, A. and J. Gutierrez-Ramos (2001) Nat. Immunol. 2:203.
4. Collins, M. et al. (2005) Genome Biol. 6:223.
5. Ling, V. et al. (2003) Genomics. 82:365.
6. Prasad, D.V. et al. (2004) J Immunol. 173:2500.
7. Dong, P. et al. (2018) Front Oncol. 8:264.
8. Suh, W.K. et al. (2003) Nat Immunol. 4:899.