Role of endogenous IFNγ in MHC-II expression. (A) Northern blots for IFNγ using total RNA from MSCs derived from 3 different BM donors. Normalization was done with a cDNA probe for 18S rRNA. (B) Representative osteogenic and chondrogenic differentiation with MSCs, stably knocked down for IFNγ. (C) Representative flow cytometry for MHC-II in MSCs knocked down for IFNγ. (D) IFNγ (10 U/mL) was re-added to cultures of knockdown MSCs. After 24 hours, the cells were studied for MHC-II by flow cytometry. Figure represent 4 experiments, each with a different donor.