Human B7-H7 protein (extracellular domain), recombinant

Description :
B7-H7 (B7 homolog 7), also know n as HHLA2 (human endogenous retrovirus-H long terminal repeat-associating protein 2), is regarded as a new member of the B7 ligand family. B7-H7 contains 1 Ig-like (immunoglobulin-like) C1-type and 2 Ig-like V-type domains while other members are typically composed of 1 Ig-like V-type and 1 Ig-like C1-type domains. Interactions between members of the B7 ligand and CD28/CTLA4 receptor families can generate positive co-stimulation and negative co-inhibition in regulating T cell responses. B7-H7 is expressed at high levels in colon, kidney, testis, lung and pancreas, and at lower levels in small intestine, liver and skeletal muscle. In immune cells, B7-H7 is highly expressed in B-cells, dendritic cells, monocytes and macrophages, but not detected in T-cells. B7-H7 was reported to regulate cell-mediated immunity by binding to a putative receptor on T lymphocytes and inhibiting the proliferation of T cells. B7-H7 has also been referred to as B-H5 (B7 homolog 5), which was identified as a specific ligand for CD28H (CD28 homolog) or TMIGD2 (transmembrane and Ig domain-containing protein 2). B7-H5 is constitutively found in macrophages and could be induced on dendritic cells in response to inflammation. The B7-H5/CD28H interaction was shown to selectively co-stimulate human T-cell growth and cytokine production via an AKT-dependent signalling cascade.