Induction of Unresponsiveness to Major Transplantable Organs in Adult Mammals A Recapitulation of Ontogeny by Irradiation and Bone Marrow Replacement

Abstract

Transplantation of renal allografts obtained from prospectively selected genotypically DLA-identical donors into supralethally irradiated dogs reconstituted with their own stored bone marrow has produced a state of unresponsiveness to these kidneys in the recipients. Eleven of 18 kidneys transplanted at 12 hours after marrow replacement currently survive with normal function and maintain life in the recipients for 757, 800, 825, 978, 1062, 1092, 1136, 1282, 1373, 1380, and 1381 days, respectively. Similar results occurred in eight of 13 allografts transplanted at 28 hours after marrow replacement, which currently survive for 349, 363, 377, 407,436,470, 485, and 513 days, respectively, and in eight of 13 kidneys grafted at 36 hours after marrow replacement, which are surviving for 197, 247, 298, 324, 337, 396, 443, and 472 days, respectively. Achievement of optimal results is dependent on the specific timing and sequence of each procedure. Only four of 16 recipients of kidneys transplanted at the time of marrow replacement were unresponsive to their allografts. Similarly, only five of 19 recipients of kidneys placed in irradiated dogs at 40 hours before marrow replacement accepted such allografts. When kidney transplants were placed into the recipients 20 hours before removal of marrow, irradiation, and reconstitution with stored marrow, only three of 21 dogs became unresponsive to such ailografts. In five of 12 instances, the recipients were also unresponsive to skin allografts obtained from their respective kidney donors. Such skin grafts currently survive for 606, 673, 687, 701, and 708 days, respectively. The remaining seven skin grafts were rejected at 28, 39,42, 84, 90, 92, and 115 days, respectively. Second- and third-set skin grafts from the same kidney donor were rejected by six of these dogs at 19, 20, 21, 29, 29, and 30 days, and at 21, 22, 23, 24, 27, and 27 days, respectively. Rejection of these skin grafts had no detectable effect on the function and survival of kidney allografts from the same source. Seven of eight skin grafts obtained from other DLA-identical donors were rejected at 13,14,16,25,28,38, and 84 days, respectively; one allograft continues to survive for 708 days. Eleven DLA-incompatible skin allografts placed on the recipients at the same time were rejected within 11-20 days. Supralethal total body irradiation and bone marrow replacement can establish in the adult canine host a privileged phase of immunological reactivity during which exposure to alloantigens produces specific long-term unresponsiveness rather than sensitization. The use of stored autologous rather than allogeneic bone marrow for reconstitution of the irradiated recipient eliminates the hazards of GVH complication usually associated with this procedure. This consideration and the apparent capacity of the tolerant host to maintain a long-term state of unresponsiveness without any further immunosuppressive therapy point to the potential relevance of the results to human transplantation.

Long-Term Study of Vascularized Free-Draining Intraperitoneal Pancreatic Segmental Allografts in Beagle Dogs

“…Also, study of this group tested the feasibility of transplanting kidneyr and pancreas in the same recipienit. Skin grafts from the kidney donors had been known to be occasionially rejected, despite unaltered renal function in the recipients (13). Table II shows that MLC reactivity was definitely present in twvo of these four specifically unresponsive recipients at the onset of the present study, nevertheless graft survival was indefinite (>10 Imlo).…”

“…An unexpected finding was that the four animals made specifically unresponsive by x irradiation, followed by autologous marrow transplantation, and then kidney transplantation, possessed CML reactivity before FDPS transplants were performed from the original kidney donors (Table II). Also, two of these animals had low-grade MLC reactivity, and this had not been present during the earlier study in these dogs (13). Differences in sensitivity of the techniques might account for the disparate MLC findings between the two studies.…”

“…The specific unresponsiveness was therefore incomplete. Taken together, the findings suggest that mechanisms other than suppressor cells or enhancement may exist for adaptation of the host to tissue allografts, and that tissue specific antigens may be important in graft rejection (13,39).…”

“…The five beagles in group II were older males and females of the Cooperstown colony, which had been inbred for many years (12). In group II, pairs of donors and recipients had been previously selected and used for kidney transplantation on the basis of extensive dog leukocyte antigen (DLA) haplotyping and pedigree-determined identity as previously described (13). A state of specific allogeneic unresponsiveness had been produced in the recipients by supralethal x irradiation, followed by reconstitution with stored autologous bone marrow and carefully timed kidney transplantation from a matched donor.…”

“…The tissue was fixed in buffered formalin and stained with hematoxylin and eosin, and also fixed in Bouin's solution and stained with aldehyde fuchsin. A small aliquot of tissue was weighed and assayed for insulin content after ex-traction in acid-ethanol (20 sponsive recipients of kidneys from donors that had been previously extensively genotyped and found to be DLA identical and MLC nonreactive before kidney transplantation (13) were tested in MLC against their specific donors again at the beginning of the present study. This group did not need immunosuppression due to the specific unresponsive state previously conferred upon them by x irradiation and autologous bone marrow transplantationi (13), and therefore, provided a control for the effects of long-term immunosuppression (group I) oIn FDPS graft function.…”