Inducible indoleamine 2,3-dioxygenase 1 and programmed death ligand 1 expression as the potency marker for mesenchymal stromal cells

A flow cytometry-based assay of MSCs post-IFN-γ exposure measuring expression of intracellular protein IDO-1 and cell surface protein PD-L1 captures two mechanisms of suppression and offers the potential of a relevant, rapid assay for MSC-mediated immune suppression that would fit with the manufacturing process.