Body distribution of syngeneic and allogeneic cells from vascularized bone marrow graft

In the previous studies we showed that vascularized bone marrow graft (VBMtx) in transplanted rat hind limb brings about complete repopulation of syngeneic recipient BM cavities and lymphoid organs within 10 days. Transplantation of an equivalent number of bone marrow cells (BMC) in suspension did not produce repopulation until day 30. In this study we present data on transplantation of allogeneic VBM and compare them with those obtained in a syngeneic combination. In the LEW or BN to LEW combination BM cells were labelled with 51Cr, injected i.v., 24 h later the hind limb was amputated and transplanted to a LEW rat. BM cells emigrated from the transplanted limb to the recipient and distributed in BM cavities and lymphoid tissues. In the LEW to LEW combination the level of radioactivity in recipient tibia was after 24 h 0.85, in spleen 2.43, in mesenteric lymph node 0.52%/g of tissue, whereas in the BN to LEW model it was 0.11, 1.83 and 0.15%, respectively. The calculated numbers of BM cells which populated recipient tissues were 8-10-times lower in the allogeneic compared with syngeneic combination. This was probably due to the nonspecific elimination of some subsets of BM cells (allogeneic BMC cytotoxicity). Administration of anti-asialo GMI antiserum to the recipient abrogated the cytotoxic effect. Taken together, major differences in kinetics of seeding and repopulation of BMC from VBMTx were found. Elimination of recipient NK cells with AAGMI antiserum attenuated the nonspecific cytotoxic effect. This protocol allows protection of the grafted BMC and increases the efficacy of the transplant.