Figure 4

Direct administration of HSCs and naïve MSCs into femur as a mixture do not have stimulatory effects on the in-vivo self-renewal of HSCs. Effects of naïve MSCs on HSCs were examined by directly transplanting HSCs and MSCs as a mixture into femur. The mixture of BMC (Ly5.1) plus MSCs or BMC alone (F1 hybrid Ly5.1/5.2) were transplanted by intrafemoral (IF) injection into recipient mice. Eight weeks after transplantation, BMCs were harvested from the injected femurs of mice from each group (n = 3 for each group), mixed together in a 1:1 ratio and subjected to limiting-dilution transplantations into secondary recipients. Engraftment of each donor origin cells in the same secondary recipient mice at 13 weeks after transplantation was discerned by surface marker (Ly5.1 or Ly5.1/5.2 hybrid). The experimental design (A) and the results of the CRU analysis for the injected femurs (2 experiments) are shown (B). CRU frequencies with 95% C.I. and CRU numbers were calculated as described in Methods.