MSCs do not specifically target antigen-reactive T cells.

Spleen cells from normal Thy1.2 C57BL/6 HY-immune female mice were stimulated with syngeneic male cells. After 7 days the proportion of HY-TCR⁺ T cells was 50% (A). These responder cells were used as such or mixed with splenocytes from Thy1.1 C57BL/6 naive female mice at a 1:2 or 1:10 ratio. Then 5 × 10⁶ cells of the different mixtures were stimulated with equal number of HY peptide-pulsed (D^bSmcy, D^bUty, A^bDby) syngeneic female cells in the presence or absence of a fixed number (10⁵) of MSCs. After 24 hours the Thy1.2⁺ cell population was assessed for numbers of peptide-specific IFN-γ⁺ cells. The graph in panel B reports the percentages of inhibition exerted by MSC on the different mixtures of responder cells. The bars show SDs.