Biolegend, 798706, Biotinylated Recombinant Human B7-H2 (ICOSL)-Fc Chimera (carrier-free)

ICOSL (B7-H2) belongs to the B7 family of immunoregulatory molecules and is a transmembrane glycoprotein of approximately 60 kD. Mature human B7-H2 consists of a 238 amino acid extracellular domain (ECD), two immunoglobulin-like domains, a 21 amino acid transmembrane segment, and a 25 residue cytoplasmic domain. Within the ECD, human B7-H2 shares 50% and 54% amino acid sequence identity with mouse and rat B7-H2, respectively. B7-H2 is expressed on antigen presenting cells such as B cells, macrophages, dendritic cells, and also in monocytes. It binds to ICOS and is expressed on activated T cells, which leads to both positive and negative effects on immune responses including its own downregulation. Mouse and human B7-H2 exhibit cross species binding to ICOS. B7-H2 interaction with ICOS is costimulatory for T cell proliferation as well as the development of B cells, plasma cells, follicular helper T cells, and germinal centers. In addition, human B7-H2 binds to CD28 and CTLA4.  The interaction of human B7-H2 and CD28 can costimulate both human and mouse naïve T cells and regulatory T cells (Treg). B7-H2 plays a role in the development of allergic asthma by enhancing Th2 biased immune responses, limiting Th17 responses, and promoting eosinophilic infiltration into the lungs. B7-H2 activation of ICOS on Tregs limits pulmonary inflammation and airway hyper-responsiveness, promotes the development of inhalational tolerance, and impairs anti-tumor immunity.