Purity
>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
Activity
Measured by its ability to inhibit anti-CD3 antibody induced IL-2 secretion in human T lymphocytes. The ED 50 for this effect is 0.5‑2.5 μg/mL.
Source
Mouse myeloma cell line, NS0-derived Phe29-Ala258, with a C-terminal 10-His tag
Accession #
N-terminal Sequence
AnalysisPhe29
Predicted Molecular Mass
26.7 kDa
SDS-PAGE
45-60 kDa, reducing conditions
6576-B7 |
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Formulation Lyophilized from a 0.2 μm filtered solution in PBS. | ||
Reconstitution Reconstitute at 100 μg/mL in PBS. | ||
Shipping The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. | ||
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
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Background: B7-H4
B7-H4, also known as VTCN1, B7x and B7S1, is a 50 ‑ 80 kDa glycosylated member of the BTN/MOG family of immunomodulatory protein (1, 2). Mature human B7-H4 consists of a 235 amino acid (aa) extracellular domain (ECD) with one Ig-like V-set domain and one Ig-like C2-set domain, a 21 aa transmembrane segment, and a 2 aa cytoplasmic tail (3 - 5). Within the ECD, human B7-H4 shares 90% aa sequence identity with mouse and rat B7-H4. It shares 22% - 28% aa sequence identity with human B7-1, B7-2, B7-H1, B7-H2, B7-H3, and PD‑L2. Alternate splicing of human B7-H4 generates an additional isoform that lacks the first Ig-like domain. B7-H4 is expressed on the surface of activated lymphocytes, macrophages, monocytes, dendritic cells, epithelial cells, and bone marrow-derived mesenchymal stem cells (4 - 8). Following binding to activated T cells, B7-H4 serves as a co‑inhibitor of the T cell response. This is accomplished by reverse signaling that can induce either cell cycle arrest, or apoptosis in B7-H4 expressing cells (3 - 5, 9, 10). B7‑H4 is up‑regulated in several carcinomas in correlation with tumor progression and metastasis (2, 7, 11, 12). A soluble form of B7-H4 is elevated in the serum of ovarian cancer, renal cell carcinoma, and rheumatoid arthritis patients, also in correlation with advanced disease status (13 - 15). Soluble B7‑H4 functions as a decoy molecule that blocks the inhibitory influence of B7‑H4 on immune activation (15). Despite evidence for the involvement of B7-H4 in immune regulation, mice deficient in its expression do not show significant immune deficiencies, suggesting compensation by other molecules in vivo (16).
References:
Yi, K.H. and L. Chen (2009) Immunol. Rev. 229:145.
Salceda, S. et al. (2005) Exp. Cell Res. 306:128.
Zang, X. et al. (2003) Proc. Natl. Acad. Sci. 100:10388.
Prasad, V.R. et al. (2003) Immunity 18:863.
Sica, G.L. et al. (2003) Immunity 18:849.
Kryczek, I. et al. (2006) J. Exp. Med. 203:871.
Tringler, B. et al. (2005) Clin. Cancer Res. 11:1842.
Xue, Q. et al. (2010) Stem Cells Dev. 19:27.
Song, H. et al. (2008) Cancer Lett. 266:227.
Park, G.B. et al. (2009) Immunology 128:360.
Zang, X. et al. (2007) Proc. Natl. Acad. Sci. 104:19458.
Krambeck, A.E. et al. (2006) Proc. Natl. Acad. Sci. 103:10391.
Simon, I. et al. (2006) Cancer Res. 66:1570.
Thompson, R.H. et al. (2008) Cancer Res. 68:6054.
Azuma, T. et al. (2009) PloS Med. 6:e1000166.
Suh, W.-K. et al. (2006) Mol. Cell. Biol. 26:6403.
Long Name:
B7 Homolog 4
Entrez Gene IDs:
79679 (Human); 242122 (Mouse)
Alternate Names:
B7h.5; B7H4; B7-H4; B7H4T-cell costimulatory molecule B7x; B7S1; B7S1VCTN1; B7x; B7XPRO1291; FLJ22418; Immune costimulatory protein B7-H4; Protein B7S1; T cell costimulatory molecule B7x; V-set domain containing T cell activation inhibitor 1; V-set domain-containing T-cell activation inhibitor 1; Vtcn1
