The potent immunosuppressive action of rapamycin has been described in many different mouse models of transplantation. In these models, rapamycin prevent or delay allograft rejection. In several models, rapamycin allowed mixed donor–recipient hematopoietic chimerism to develop facilitating tolerance induction. In our own experience, we observed that rapamycin synergized with CD8+ T cell depletion and coreceptor/costimulation blockade to induce long-term survival of Balb/C to C57Bl/6 heterotopic limb allograft. Herein, we describe immunosuppression cocktails containing rapamycin and methods to evaluate several read outs associated with tolerance induction such as mixed donor–recipient hematopoietic chimerism and in vitro or in vivo recipient alloreactivity.
