Recombinant Human ICOS ligand (ICOSLG), partial (Active)

ICOSLG (B7-H2) plays a critical role in T cell costimulation and is implicated in tumor immune evasion, making it a key target for immuno-oncology research. This recombinant human ICOSLG fragment (aa 19–258) demonstrates robust binding to its cognate receptor ICOS with an EC50 of 29.04–43.59 ng/ml in functional ELISA, supporting use as a coating antigen for antibody screening, an ELISA positive control, or a ligand in T cell activation and proliferation assays using primary PBMCs or purified T cell subsets. Produced in mammalian cells with a C-terminal 6×His tag, the protein retains native-like glycosylation patterns important for receptor engagement fidelity. Endotoxin levels below 1.0 EU/μg minimize LPS-driven artifacts in sensitive immune cell functional assays, while purity exceeding 95% by SDS-PAGE satisfies the quality thresholds commonly required for in vivo tumor biology models and signaling pathway studies examining ICOS-mediated PI3K/AKT activation.