Figure 1. Experimental protocol for liposomal clodronate enhancement of hematopoietic chimerism and donor-specific skin allograft tolerance.

Recipient C57BL/6 mice were pretreated i.v. with liposomal clodronate or control liposomes at the times indicated by the blue arrows before the day of allogeneic BM transplantation (day 0). Immunosuppressive agents were then given where indicated by the green arrows (see Materials and Methods for doses and details). Donor-specific tolerance was tested by applying both BALB/c and CBA/Ca skin allografts on the dorsum of recipient mice at both 90 days (primary allografts) and 180 days (secondary allografts) after BM transplantation. Animals were sacrificed on day 225 post BM transplantation.