Analysis of human MSCs following IFNγ exposure and immune effects in mice. (A) Flow cytometry analysis on MHC class I and MHC class II was carried out on cultured primary human MSCs before and after in vitro exposure to IFNγ, as indicated in “Materials and methods”. The dashed line represents the isotype control, the solid line represents the specific antibody, and the bolder line represents the specific antibody after IFNγ. (B) As also detailed in “Materials and methods,” human MSCs (black box) were implanted in Balb/c (white dot) recipients; splenocytes were recovered 15 days later and cultured in vitro for 24 hours with human MSCs (▪) or Balb/c MSCs (□); and supernatants were tested for mouse IFNγ by ELISA (n = 3 per group). No IFNγ release was detected when splenocytes from untreated naive Balb/c mice (▦) were cocultured with xenogeneic human MSCs (ND indicates nondetected). Data are shown as average ± SD.