FIG. 1.

MSCs are low-immunogenic cells. Levels of MHC-I (A) and MHC-II (B). MSCs (dashed line) express low levels of MHC-I and are negative for MHC-II, while BMCs (gray line) express high levels of MHC-I and low levels of MHC-II. As a positive control of MHC-I and MHC-II expression, we used Sprague-Dawley rat splenocytes (black line). We also quantified the percentage of DSA against third-party injected cells (MSCs or BMCs) 1 week after the injection (C), and observed no antibodies in MSC-injected animals (open bars) and positive MHC-I in BMC-injected animals (gray bars) (^bP=0.005, ^cP=0.06). MSC, mesenchymal stem cell; BMCs, bone marrow mononuclear cells; DSA, donor specific antibody.