B7H4, aa29-258, Recombinant, Human (V-set Domain-containing T-cell Activation Inhibitor 1, B7h.5, Immune Costimulatory Protein B7-H4, Protein B7S1, T-cell Costimulatory Molecule B7x, VTCN1, UNQ659/PRO1291)

B7-H4, also known as VTCN1, B7x and B7S1, is a 50-80kD glycosylated member of the BTN/MOG family of immunomodulatory protein (1, 2). Mature human B7-H4 consists of a 235aa extracellular domain (ECD) with one Ig-like V-set domain and one Ig-like C2-set domain, a 21aa transmembrane segment, and a 2aa 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).\n\nSource: \nRecombinant corresponding to aa29-258 from human B7-H4, fused with 10-His tag at C-terminal, expressed in myeloma cell line, NSO.\n\nMolecular Weight: \n~26.7kD\n\nEndotoxin Level:\n(same/less than)1EU/1ug (LAL)\n\nBiological Activity:\nMeasured by its ability to be proteolytically processed by SENP1. 50% of 1ug recombinant human SUMO1 is cleaved by <10ng of rhSENP or 95% of 1ug rhSUMO1 is cleaved by <25ng of rhSENP, as measured under the described conditions. \n\nStorage and Stability:\nLyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with PBS. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Reconstituted product is stable for 6 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

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SPECIFICATIONS

Catalog Number

B0000-35G

Size

50ug

Form

Supplied as a lyophilized powder in PBS. Reconstitute with PBS to 100ug/ml.

Purity

~95% (SDS-PAGE)

References

1. Yi, K.H. and L. Chen (2009) Immunol. Rev. 229:145. 2. Salceda, S. et al. (2005) Exp. Cell Res. 306:128. 3. Zang, X. et al. (2003) Proc. Natl. Acad. Sci. 100:10388. 4. Prasad, V.R. et al. (2003) Immunity 18:863. 5. Sica, G.L. et al. (2003) Immunity 18:849. 6. Kryczek, I. et al. (2006) J. Exp. Med. 203:871. 7. Tringler, B. et al. (2005) Clin. Cancer Res. 11:1842. 8. Xue, Q. et al. (2010) Stem Cells Dev. 19:27. 9. Song, H. et al. (2008) Cancer Lett. 266:227. 10. Park, G.B. et al. (2009) Immunology 128:360. 11. Zang, X. et al. (2007) Proc. Natl. Acad. Sci. 104:19458. 12. Krambeck, A.E. et al. (2006) Proc. Natl. Acad. Sci. 103:10391. 13. Simon, I. et al. (2006) Cancer Res. 66:1570. 14. Thompson, R.H. et al. (2008) Cancer Res. 68:6054. 15. Azuma, T. et al. (2009) PloS Med. 6:e1000166. 16. Suh, W.-K. et al. (2006) Mol. Cell. Biol. 26:6403.