MSCs have no effect on expansion of EBV- or CMV-specific CTL. Established (A) EBV-CTL or (B) CMV-CTL were stimulated with irradiated (irr) autologous LCL or pp65-pulsed LCL, respectively, in the presence or absence or MSCs for 5 days and stained with virus-specific pentamers. Representative FACS plot for stainings with 2 EBV pentamers and 2 CMV pentamers gated on CD3⁺CD8⁺ T cells are shown. (C) 4 EBV-CTL lines were stimulated with irr autologous LCL in the presence or absence of MSCs for 5 days and analyzed for [³H]thymidine incorporation. (D) Representative histogram from one of the EBV-CTL lines (gated on CD3⁺ T cells) showing similar dilution of CFSE dye after stimulation with LCL when cultured with or without MSCs.