IMRCs expanded on HAMCs maintain cell stemness and immunomodulatory capabilities in stirred bioreactors. A. MSC-specific markers of IMRCs harvested from HAMCs (100–200 μm HAMC100). Isotype antibodies were used as controls for gating. B. Karyotyping of IMRCs harvested from HAMC. C. Distribution of cell diameters of IMRCs harvested from monolayer culture or HAMCs expansion. D. Viability of IMRCs harvested from monolayers or HAMC in clinical injection buffer over time at 4 °C. E. Representative immunofluorescence staining of IMRC-laden microcarriers in situ after they were induced to undergo osteogenic differentiation (osteocalcin), adipogenic differentiation (FABP-4), and chondrogenic differentiation (aggrecan). Scale bar, 100 μm. F. Morphology of IMRCs harvested from monolayers and HAMCs before and after IFN-γ stimulation. Scale bar, 100 μm. G. Real-time qPCR for IDO1 mRNA in IMRCs harvested from monolayers and HAMCs before and after IFN-γ (0, 50 and 100 ng/mL) treatment. H. The inhibitory effects of IMRCs on activated PBMC (CD3/28 and IL-2 costimulated) proliferation at ratios of 1:2, 1:20 and 1:100 in vitro.