>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
<0.10 EU per 1 μg of the protein by the LAL method.
Measured by its binding ability in a functional ELISA. When Recombinant Human CD28H/IGPR-1 is immobilized
at 0.125 μg/mL, 100 μL/well, the concentration of Recombinant Human B7-H7/HHLA2 Fc Chimera (Catalog # 8084-B7) that produces 50% of the optimal binding response is approximately 0.2-1 μg/mL.
Human embryonic kidney cell, HEK293-derived Leu23-Gly150, with a C-terminal 6-His tag
When Recombinant Human CD28H/IGPR-1 (Catalog # 9236-TR) isimmobilized at 0.125 μg/mL, Recombinant Human B7-H7/HHLA2 Fc Chimera (Catalog # 8084-B7) binds with an ED50 of 0.2-1 μg/mL.
CD28 homolog (CD28H), also called TMIG2 and IGPR-1, is a 55 kDa glycosylated transmembrane protein that shares approximately 10% amino acid (aa) sequence identity with CD28, CTLA-4, ICOS, and PD-1. CD28H is composed of a single extracellular immunoglobulin variable-like domain (IgV) (aa 23-109), a transmembrane domain (aa 151-171), and a long cytoplasmic domain (aa172-282). CD28H is constitutively expressed on naive T and NK cells. Similar to the interaction of B7 with CD28, the interaction of CD28H with B7-H7 activates the Akt-dependent signaling cascade and promotes the proliferation and activation of newly generated peripheral effector and memory T cells (1, 2). CD28H is additionally expressed in the skin and epithelium lining the lung, airway, mammary gland, and gastrointestinal tract (3). It regulates cellular morphology, focal adhesion contact formation, and cell migration (3, 4). CD28H also participates in angiogenesis in vitro (3). CD28H interacts with multiple cytoskeletal proteins including Actin, Paxillin, SPIN90, CACNB2, and BPAG1. Interactions between the cytoplasmic proline-rich domain of CD28H and SPIN90 modulate the activity of CD28H in both angiogenesis and cell adhesion (3, 5).
Zhu, Y. et al. (2013) Nat. Commun. 4:2043.
Parry, R.V. et al. (2003) J.Immunol. 171:166.
Rahimi, N. et al. (2012) Mol. Biol. Cell. 23:1646.
Huang, C. et al. (2003) Nature 424:219.
Kaneko, T. et al. (2008) Front. Biosci. 13:4938.
Transmembrane And Immunoglobulin Domain Containing 2