ICOS/CD278 Extracellular Domain (human, recombinant)

Inducible T cell co-stimulator (ICOS) is a glycoprotein and member of the CD28/B7 family of co-stimulatory receptors that promotes T cell activation. It exists as a membrane-bound disulfide-linked homodimer and contains a leader peptide, an extracellular domain that interacts with ICOS ligand (ICOSL), and a cytoplasmic tail that mediates association with PI3K and is critical for T cell activation. ICOS is expressed on activated CD4+ and CD8+ T cells following T cell receptor crosslinking and/or co-stimulation by CD28. ICOS co-stimulation of T cells induces production of IL-4, IL-5, IL-6, IFN-gamma (Cay-32008, Cay-32078), TNF-alpha (Cay-32020, Cay-32069), and GM-CSF (Cay-32044, Cay-32079), but not IL-2, and superinduces production of IL-10, as well as prevents T cell apoptosis. Human melanoma cells express ICOSL and promote the expansion of ICOS+ IL-10-secreting regulatory T cells, which is positively correlated with unfavorable clinical outcomes. Administration of an anti-ICOS monoclonal antibody ameliorates mucosal inflammation and damage in a mouse model of T helper cell-induced chronic colitis. Cayman's ICOS/CD278 Extracellular Domain (human, recombinant) protein can be used for ELISA. This protein is a disulfide-linked homodimer. The reduced monomer, comprised of ICOS (amino acids 21-141) fused to His-tagged human IgG1 Fc at its C-terminus, consists of 386 amino acids, has a calculated molecular weight of 41.6 kDa, and a predicted N-terminus of Glu21 after signal peptide cleavage. As a result of glycosylation, the monomer migrates at approximately 50 kDa by SDS-PAGE under reducing conditions.Synonyms: Activation-inducible Lymphocyte Immunomediatory Molecule, AILIM, CVID1, Inducible T Cell Costimulator. Purity: >90% estimated by SDS-PAGE. Endotoxin Testing: <1.0 EU/µg determined by the LAL endotoxin assay. Amino Acids: 21-141. MW: 41.6 kDa. Formulation: (Request formulation change), Lyophilized from sterile PBS, pH 7.4.