Long-term observations of autoimmune-prone mice treated for autoimmune disease by allogeneic bone marrow transplantation.

Long-term effects of allogeneic bone marrow transplantation (ABMT) across major histocompatibility complex barriers were studied in (NZB x NZW)F1 (B/W), BXSB, and MRL/Mr-lpr-lpr (MRL/lpr) mice with established autoimmune disease at the time of ABMT. In the BXSB or B/W mice, ABMT cured all aspects of autoimmune disease. Glomerular damage, revealed by histological study was dramatically improved. Serological abnormalities and immunologic functions also were normalized. Correction of autoimmune disease and advanced renal disease in BXSB and B/W mice regularly lasted greater than 5-6 mo and even 1 yr after ABMT. In the MRL/lpr mice, however, autoimmune and renal disease at first improved but then recurred after ABMT, apparently because of intolerance of mice for high doses of irradiation and a high degree of resistance of recipient stem cells to irradiation. In this model, H-2 typing revealed that by the time of relapse, immunocompetent cells of the chimeric mice had been replaced by host (MRL/lpr; H-2k) cells. B220+ Ly-1+ cells, present in increased numbers in untreated MRL/lpr mice, initially returned to normal levels after ABMT but then reappeared in the MRL/lpr mice that had received marrow from donors having few such lymphocytes. Thus, our results show that MRL/lpr mice possess abnormal radioresistant stem cells and provide impressive evidence that the origin of autoimmune diseases in this strain, as in the several other strains studied, residues in abnormalities present in stem cells.     

Mixed peripheral blood stem cell transplantation for autoimmune disease in BXSB/MpJ mice

We examined whether mixed allogeneic transplantation with syngeneic plus allogeneic peripheral blood stem cells (PBSCs) is sufficient to interrupt autoimmune processes in BXSB mice and confer a potential therapeutic option for the treatment of patients with autoimmune diseases. Eight-week-old BXSB mice were lethally irradiated and reconstituted with BALB/c (H-2(d))+BXSB (H-2(b)) PBSCs, in which the number of injected allogeneic progenitor cells was 5 times that of syngeneic progenitor cells. The survival of mixed PBSC chimeras (BALB/c+BXSB-->BXSB) was 80% at the age of 48 weeks, whereas that of full chimeras (BALB/c-->BXSB) was 90%. Mixed PBSC transplantation (PBSCT) prevented the production of anti-DNA antibodies and the development of lupus nephritis in BXSB recipients and induced tolerance to both allogeneic and syngeneic antigens. Moreover, mixed chimeras exhibited immunological functions superior to fully allogeneic chimeras. On the other hand, increases in the number of BXSB PBSCs resulted in the transfer of lupus nephritis in BXSB+BALB/c-->BALB/c mice. Thus, the number of hematopoietic progenitor cells from normal mice proved critical to the prevention of autoimmune diseases. We propose that mixed allogeneic PBSCT for the interruption of the autoimmune process can be carried out by injecting increased numbers of allogeneic normal hematopoietic progenitor cells to prevent the relapse of autoimmune diseases, although it is necessary to decide upon a minimum dose of syngeneic PBSCs to achieve the desired beneficial effects on autoimmunity.     

Successful liver allografts in mice by combination with allogeneic bone marrow transplantation.

Successful liver allografts were established by combination with allogeneic bone marrow transplantation. When liver tissue of BALB/c (H-2d) or C57BL/6J (H-2b) mice was minced and grafted under the kidney capsules of C3H/HeN (H-2k) mice, it was rejected. However, when C3H/HeN mice were irradiated and reconstituted with T-cell-depleted BALB/c or BALB/c nu/nu bone marrow cells, or with fetal liver cells of BALB/c mice, they accepted both donor (stem-cell)-type (BALB/c) and host (thymus)-type (C3H/HeN) liver tissue. Assays for both mixed-lymphocyte reaction and induction of cytotoxic T lymphocytes revealed that the newly developed T cells were tolerant of both donor (stem-cell)-type and host (thymus)-type major histocompatibility complex determinants. We propose that liver allografts combined with bone marrow transplantation should be considered as a viable therapy for patients with liver disease such as liver cirrhosis and hepatoma.     

Prevention of development of autoimmune disease in BXSB mice by mixed bone marrow transplantation

Transplantations of fully allogeneic, autoimmune-resistant T-cell-depleted marrow (TCDM) plus syngeneic, autoimmune-prone TCDM into lethally irradiated BXSB mice were carried out to investigate the ability of the mixed bone marrow transplantation (BMT) to prevent development of autoimmune disease and, at the same time, to reconstitute fully the immunity functions of heavily irradiated BXSB recipients. Male BXSB mice were engrafted with mixed TCDM from both allogeneic, autoimmune-resistant BALB/c mice and syngeneic, autoimmune-prone BXSB mice. BMT with mixed TCDM from both resistant and susceptible strains of mice (mixed BMT) prolonged the median life span and inhibited development of glomerulonephritis in BXSB mice. BMT with mixed TCDM also prevented the formation of anti-DNA antibodies that is typically observed in male mice of this strain. Moreover, mixed BMT reconstituted primary antibody production in BXSB recipients, so that no annoying immunodeficiencies that are regularly observed in fully allogeneic chimeras were present in the recipient of the mixed TCDM. These findings indicate that transplanting allogeneic, autoimmune-resistant TCDM plus syngeneic, autoimmune-prone TCDM into lethally irradiated BXSB mice prevents development of autoimmune disease in this strain of mice. In addition, this dual BMT reconstitutes the immunity functions and avoids the immunodeficiencies that occur regularly in fully allogeneic chimeras after total-body irradiation.     

Organ-specific and systemic autoimmune diseases originate from defects in hematopoietic stem cells.

Transplantation of bone marrow cells from nonobese diabetic (NOD) mice, a model for type 1 diabetes mellitus, to C3H/HeN mice, which express I-E alpha molecules and have aspartic acid at residue 57 of the I-A beta chain, induced insulitis followed by overt diabetes in the recipient C3H/HeN mice more than 40 weeks after bone marrow transplantation. When cyclosporin A, which perturbs T-cell functions, was injected intraperitoneally into [NOD----C3H/HeN] chimeric mice daily for 1 month, the chimeric mice developed insulitis and overt diabetes within 20 weeks following bone marrow transplantation. Transplantation of bone marrow cells from (NZW x BXSB)F1 mice, which develop lupus nephritis, myocardial infarction, and idiopathic thrombocytopenic purpura, into C3H/HeN or C57BL/6J mice induced in the recipient strains both lupus nephritis and idiopathic thrombocytopenic purpura more than 3 months after transplantation. Transplantation of a stem-cell-enriched population from (NZW x BXSB)F1 mice into normal mice also induced autoimmune disease in the recipients. These results indicate that both systemic autoimmune disease and organ-specific autoimmune disease originate from defects that reside within the stem cells; the thymus and environmental factors such as sex hormones appear to act only as accelerating factors.     

Transplantation of wheat germ agglutinin-positive hematopoietic cells to prevent or induce systemic autoimmune disease.

Hematopoietic stem cell defects are thought to be involved in the etiopathogenesis of systemic autoimmune disease. Positively selected, stem cell-enriched populations of wheat germ agglutinin-positive (WGA+) low-density bone marrow and fetal liver cells from normal and autoimmune-prone mice were used to determine whether reciprocal transplantation of stem cells between normal and autoimmune-prone mice inhibits or causes development of autoimmune disease. NZB recipients of DBA/2 stem cell populations analyzed greater than 100 days after bone marrow or fetal liver cell transplantation showed decreased levels of anti-DNA antibodies and decreased glomerular lesions when compared with nontreated NZB mice or NZB recipients of NZB stem cell preparations. Female DBA/2 recipients of WGA+ NZB bone marrow cell or fetal liver cell transplants exhibited elevated serum autoantibody levels and developed glomerular lesions characteristic of NZB mice when analyzed greater than 100 days after transplantation. These pathological disturbances were not observed in DBA/2 recipients of DBA/2 stem cell preparations. The data indicate that WGA+ stem cells from autoimmune-prone NZB mice contain the genetic defects responsible for the development of systemic autoimmune disease.     

Effective treatment of autoimmune disease and progressive renal disease by mixed bone-marrow transplantation that establishes a stable mixed chimerism in BXSB recipient mice

Male BXSB mice spontaneously develop autoimmune disease with features similar to systemic lupus erythematosus. To determine whether this autoimmune disease can be treated as well as prevented by bone-marrow transplantation (BMT) and, at the same time, whether the immunity functions of lethally irradiated recipients can be reconstituted fully, male BXSB mice were engrafted with mixed T cell-depleted marrow (TCDM) both from fully allogeneic autoimmune-resistant BALB/c mice and from syngeneic autoimmune-prone BXSB mice, after the onset of autoimmune disease in the recipient mice. BMT with mixed TCDM from both resistant and susceptible strains of mice (mixed BMT) established stable mixed chimerism, prolonged the median life span, and arrested development of glomerulonephritis in BXSB mice. BMT with mixed TCDM also reduced the formation of anti-DNA antibodies that are observed typically in male mice of this strain. Furthermore, mixed BMT reconstituted the primary antibody production in BXSB recipients impressively. These findings indicate that transplantation of allogeneic autoimmune-resistant TCDM plus syngeneic autoimmune-prone TCDM into lethally irradiated BXSB mice can be used to treat autoimmune and renal disease in this strain of mice. In addition, this dual bone-marrow transplantation reconstitutes the immunity functions and avoids the immunodeficiencies that occur regularly in fully allogeneic chimeras after total body irradiation. This report describes an effective treatment of progressive renal disease and autoimmunity by establishing a stable mixed chimerism of TCDM transplantation from allogeneic autoimmune-resistant BALB/c mice plus syngeneic autoimmune-prone BXSB mice into BXSB mice.     

Thymus transplantation, a critical factor for correction of autoimmune disease in aging MRL/+mice.

MRL/MP-+/+ (MRL/+) mice develop pancreatitis and sialoadenitis after they reach 7 months of age. Conventional bone marrow transplantation has been found to be ineffective in the treatment of these forms of apparent autoimmune disease. Old MRL/+ mice show a dramatic thymic involution with age. Hematolymphoid reconstitution is incomplete when fetal liver cells (as a source of hemopoietic stem cells) plus fetal bone (FB; which is used to recruit stromal cells) are transplanted from immunologically normal C57BL/6 donor mice to MRL/+ female recipients. Embryonic thymus from allogeneic C57BL/6 donors was therefore engrafted along with either bone marrow or fetal hematopoietic cells (FHCs) plus fragments of adult or fetal bone. More than seventy percent of old MRL/+ mice (> 7 months) that had been given a fetal thymus (FT) transplant plus either bone marrow or FHCs and also bone fragments survived more than 100 days after treatment. The mice that received FHCs, FB, plus FT from allogeneic donors developed normal T cell and B cell functions. Serum amylase levels decreased in these mice whereas they increased in the mice that received FHCs and FB but not FT. The pancreatitis and sialoadenitis already present at the time of transplantations were fully corrected according to histological analysis by transplants of allogeneic FHCs, FB and FT in the MRL/+ mice. These findings are taken as an experimental indication that perhaps stem cell transplants along with FT grafts might represent a useful strategy for treatment of autoimmune diseases in aged humans.     

Prevention of type I diabetes in nonobese diabetic mice by allogenic bone marrow transplantation.

An animal model [the nonobese diabetic (NOD) mouse] for type I diabetes features a striking infiltration of T cells into the pancreatic islets. This infiltration selectively destroys beta cells. Most of the T cells are Lyt-1+, but some are Lyt-2+,3+. Transfer experiments using parabiosis revealed that insulitis can be transferred within 2 weeks after parabiosis to immunoincompetent thymectomized mice. When NOD mice (6 mo old) were irradiated and reconstituted with bone marrow cells from young BALB/c nu/nu mice (less than 2 mo old), the NOD mice exhibited neither insulitis nor overt diabetes. Deposits of immunoglobulin in mesangial areas of the glomeruli disappeared within 3 mo after bone marrow transplantation in such irradiated allogeneic bone marrow reconstituted mice. Assays for immunological functions, including mitogen response and mixed lymphocyte reaction, revealed that both T- and B-cell functions were increased in NOD mice with overt diabetes. NOD mice reconstituted with BALB/c nu/nu bone marrow cells displayed normal T- and B-cell functions. The newly developed T cells in the allogeneic bone marrow recipients are tolerant to cells with both donor- and host-type major histocompatibility complex determinants. These results suggest that bone marrow transplantation may ultimately be developed as a component of a strategy to be employed for treatment of type I diabetes in humans.     

Transplantation of Autoimmune Potential. I. Development of Antinuclear Antibodies in H-2 Histocompatible Recipients of Bone Marrow from New Zealand Black Mice

Antinuclear autoantibodies (ANA) appeared in the plasma of lethally irradiated H-2d histocompatible DBA/2 and BALB/c mice several weeks after intravenous transplantation of 2 to 4 x 10(6) bone marrow cells from 3-week-old animals of the autoimmune New Zealand Black (NZB) strain. Little or no ANA development was observed in DBA/2 or BALB/c strains when syngeneic or nonautoimmune allogeneic marrow was grafted, or when NZB marrow was injected into untreated DBA mice or mice receiving 200 rads of x-irradiation. Transfer of 5 x 10(6) spleen cells from 8-day-old NZB mice into lethally irradiated BALB/c mice effected substantial ANA formation by the ninth day after transfer, compared to a 20-day latency following transfer of the same number of bone marrow cells. This earlier conversion with splenocytes may have been due to the presence of immunocompetent T and B cells, since stem cell numbers of the two tissues were similar. Transplantation of NZB marrow to lethally irradiated H-2 incompatible SJL/J (H-2s) and C57B1/6 (H-2b) strains brought about less ANA conversion than the transfer of compatible (SJL x NZB)F1 and (C57B1 x NZB)F1 marrow cells to the respective nonautoimmune SJL or C57B1 parental strain. Graft-versus-host reactions thus did not appear to play a requisite or determining role in the autoimmune development observed following grafting of NZB hemopoietic tissues. Reconstitution of lethally irradiated NZB mice with BALB/c or SJL/J bone marrow depressed the recurrence of ANA for 30 days, compared to rapid ANA recovery following NZB marrow injection. The characteristics that ultimately provoke or permit spontaneous auto-reactivity are inherent in the hemopoietic stem cell population of the NZB strain.     

Prevention of autoimmune hearing loss in MRL/lpr mice by bone marrow transplantation

We examined the effects of bone marrow transplantation (BMT) on immune-mediated inner ear diseases in MRL/Mp-lpr/lpr (MRL/lpr) mice, which manifest not only lupus nephritis but also sensorineural hearing loss (SNHL) at the age of 20 weeks. These mice were treated with cyclophosphamide (CY) and irradiation (5 Gy x 2), followed by the transplantation of bones plus bone marrow cells from allogeneic normal C57BL/6 mice at the age of 12 weeks. Hematolymphoid cells were reconstituted with donor-derived cells 3 months after BMT. Thus-treated MRL/lpr mice showed neither lupus nephritis nor SNHL even 24 weeks after BMT. No pathological findings were observed in either glomeruli or cochleae. These findings suggest that BMT can be used to prevent the development of autoimmune SNHL in MRL/lpr mice.     

New strategies for BMT,organ transplantation,and regeneration therapy

Bone marrow transplantation (BMT) is becoming a powerful strategy for the treatment of hematologic disorders, congenital immunodeficiencies, metabolic disorders and also autoimmune diseases. We have previously found using various animal models for spontaneous autoimmune diseases, that allogeneic bone marrow transplantation (allo BMT) can be used to prevent and treat various autoimmune diseases. In addition, we have found that autoimmune diseases are stem cell disorders. However, in MRL/lpr mice, which are radiosensitive (<8.5 Gy), we found that conventional BMT had only a transient effect on autoimmune diseases, which were found to recur. Therefore, we concentrated on discovering new strategies to prevent and treat autoimmune diseases in the radiosensitive and chimeric-resistant MRL/lpr mouse. Using MRL/lpr mice, we established a new method for allo BMT. In this method, whole bone marrow cells (BMCs), containing a small number of T cells and mesenchymal stem cells (MSCs), were directly injected into the bone marrow cavity (intra-bone marrow [IBM]-BMT). MRL/lpr mice treated with IBM-BMT survived more than 2 years without showing the symptoms of autoimmune diseases. To apply this BMT method to humans, we have also established a new method for BMC harvesting using cynomolgus monkeys. In this method, BMCs are harvested from the long bones using a "Perfusion Method" (PM) and the whole BMCs (including MSCs) are then injected directly into the IBM. We believe that this new method will become a powerful strategy for the treatment of various intractable diseases, including age-associated diseases such as osteoporosis.     

New Strategies for BMT,Organ Transplantation,and Regeneration Therapy

Bone marrow transplantation (BMT) is becoming a powerful strategy for the treatment of hematologic disorders, congenital immunodeficiencies, metabolic disorders and also autoimmune diseases.

We have previously found using various animal models for spontaneous autoimmune diseases, that allogeneic bone marrow transplantation (allo BMT) can be used to prevent and treat various autoimmune diseases. In addition, we have found that autoimmune diseases are stem cell disorders. However, in MRL/lpr mice, which are radiosensitive (<8.5 Gy), we found that conventional BMT had only a transient effect on autoimmune diseases, which were found to recur. Therefore, we concentrated on discovering new strategies to prevent and treat autoimmune diseases in the radiosensitive and chimeric-resistant MRL/lpr mouse.

Using MRL/lpr mice, we established a new method for allo BMT. In this method, whole bone marrow cells (BMCs), containing a small number of T cells and mesenchymal stem cells (MSCs), were directly injected into the bone marrow cavity (intra-bone marrow [IBM]-BMT). MRL/lpr mice treated with IBM-BMT survived more than 2 years without showing the symptoms of autoimmune diseases.

To apply this BMT method to humans, we have also established a new method for BMC harvesting using cynomolgus monkeys. In this method, BMCs are harvested from the long bones using a "Perfusion Method" (PM) and the whole BMCs (including MSCs) are then injected directly into the IBM. We believe that this new method will become a powerful strategy for the treatment of various intractable diseases, including age-associated diseases such as osteoporosis.     

Intra-bone marrow injection of allogeneic bone marrow cells: a powerful new strategy for treatment of intractable autoimmune diseases in MRL/lpr mice

Intractable autoimmune diseases in chimeric resistant MRL/lpr mice were treated by a new bone marrow transplantation (BMT) method consisting of fractionated irradiation, 5.5 Gy x 2, followed by intra-bone marrow (IBM) injection of whole bone marrow cells (BMCs) from allogeneic normal C57BL/6 (B6) mice (5.5 Gy x 2 + IBM). In MRL/lpr mice treated with this method, the number of donor-derived cells in the bone marrow, spleen, and liver rapidly increased (almost 100% donor-derived cells by 14 days after the treatment), and the number of donor-derived hemopoietic progenitor cells concomitantly increased. Furthermore, donor-derived stromal cells were clearly detected in the cultured bone pieces from MRL/lpr mice treated with 5.5 Gy x 2 + IBM. All the recipients thus treated survived more than 1 year (> 60 weeks after birth) and remained free from autoimmune diseases. Autoantibodies decreased to almost normal levels, and abnormal T cells (Thy1.2(+)/B220(+)/CD4(-)/CD8(-)) disappeared. Hematolymphoid cells were reconstituted with donor-derived cells, and newly developed T cells were tolerant to both donor (B6)-type and host (MRL/lpr)-type major histocompatibility complex determinants. Successful cooperation was achieved among T cells, B cells, and antigen-presenting cells when evaluated by in vitro antisheep red blood cell responses. These findings clearly indicate that this new strategy (IBM-BMT) creates the appropriate hemopoietic environment for the early recovery of hemopoiesis and donor cell engraftment, resulting in the complete amelioration of intractable autoimmune diseases in chimeric resistant MRL/lpr mice without recourse to immunosuppressants. This strategy would therefore be suitable for human therapy.     

Pluripotential hemopoietic stem cells in adult mouse brain.

Single cell suspensions of adult mouse brain were shown to contain large numbers of pluripotential hemopoietic stem cells as detected by the ability to form hemopoietic colonies in the spleens of irradiated hosts. These colony forming unit, spleen (CFU-s) cells derived from brain gave rise to colonies identical in morphology and histology to those of bone marrow-derived CFU-s. The average number of CFU-s obtained per 10(5) dissociated adult brain cells was 14, whereas other adult tissues such as lung, kidney, heart, and thymus contained insignificant CFU-s levels when tested. As the level of CFU-s in adult blood is less than 1 per 10(6) nucleated cells, blood contamination does not contribute to the high levels found in adult brain. Individual spleen colonies isolated from irradiated CBA (H-2k) recipients injected with (BALB/c x CBA)F1 (H-2d x H-2k) brain cells were shown by immunofluorescence to contain cells bearing surface H-2d molecules, thus indicating that the colonies arose from the brain cell inoculum and were not endogenously derived. The surface phenotype of brain- and bone marrow-derived CFU-s was found to differ in that brain CFU-s could be inhibited by prior incubation with a monoclonal antibrain antibody B2A2, whereas bone marrow CFU-s were not. Further differences were found between brain and bone marrow CFU-s in the congenitally anemic Wf/Wf mice. These mice were shown to have a very few CFU-s in the adult bone marrow, whereas the brain contained normal adult levels. The large number of hemopoietic stem cells in the brain may indicate an essential requirement for the continual generation of cells such as microglia or phagocytic cells, without the disruption of the blood-brain barrier.     

Treatment of intractable autoimmune diseases in MRL/lpr mice using a new strategy for allogeneic bone marrow transplantation

A new bone marrow transplantation (BMT) method for treating severe autoimmune diseases in chimeric resistant MRL/lpr mice is presented. The method consists of fractionated irradiation (5.5 Gy x 2), followed by portal venous (PV) injection of whole bone marrow cells (BMCs) from allogeneic normal C57BL/6 (B6) mice and intravenous (IV) injection of whole B6 BMCs 5 days after the PV injection (abbreviated as 5.5 Gy x 2 + PV + IV). All recipients survived more than 1 year after this treatment (more than 64 weeks after birth). Abnormal T cells (Thy1.2(+)/B220(+)/CD3(+)/CD4(-)/CD8(-)) present in MRL/lpr mice before the treatment disappear, and hematolymphoid cells are reconstituted with donor-derived cells. The treated mice are free from autoimmune diseases. Levels of autoantibodies (IgG/IgM anti-ssDNA antibodies and IgG/IgM rheumatoid factors) decrease to normal levels. Successful cooperation is achieved among T cells, B cells, and antigen-presenting cells (APCs) of the treated MRL/lpr mice when evaluated by in vitro anti-SRBC responses. Newly developed T cells are tolerant to both donor (B6)-type and host (MRL/lpr)-type major histocompatibility complex (MHC) determinants. These findings clearly indicate that severe autoimmune diseases in MRL/lpr mice are completely ameliorated by the treatment without recourse to immunosuppressants, and that the treated MRL/lpr mice show normal immune functions, strongly suggesting that this strategy would be applicable to humans. (Blood. 2000;95:1862-1868)     

Marrow transplantation from tolerant donors to treat and prevent autoimmune diseases in BXSB mice.

Autoimmune-prone BXSB male mice were supralethally irradiated and transplanted with CBA/H bone marrow cells. A complete and long-term chimerism was established when donor mice had been induced to develop tolerance of BXSB male antigens by combined treatment with BXSB male spleen cells and cyclophosphamide. Such chimeras did not express autoimmune phenomena or develop lethal autoimmune manifestations. Nor did the recipient mice develop the wasting syndrome or evidence of persistent immunodeficiencies that have been seen in other strains of autoimmune-resistant mice that had been transplanted with bone marrow cells across major histocompatibility complex barriers following an initial purging of the bone marrow of Thy-1+ cells using anti-Thy-1+C.     

New strategies for allogeneic BMT

In humans, the success rate of BMT across major histocompatibility complex (MHC) barriers is lowered by graft-versus-host disease (GvHD), graft rejection and incomplete T-cell recovery. To prevent GvHD, we attempted to minimize the contamination of bone marrow cells (BMCs) with T cells from the peripheral blood when donor BMCs were collected, finally establishing a new 'Perfusion Method' using cynomolgus monkeys. There was significantly less contamination of BMCs with T cells in this method (<6%) than in the conventional 'Aspiration Method' (>20%) consisting of multiple aspirations of BMCs from the iliac crest. Using radio-sensitive and chimerism-resistant MRL/lpr mice, we also established a new method for allogeneic (allo) BMT and organ allografts. In this method, whole BMCs, containing a small number of T cells and mesenchymal stem cells (MSCs), were directly injected into the bone marrow cavity (intrabone marrow [IBM]-BMT). MRL/lpr mice treated with IBM-BMT survived more than 2 years without showing the symptoms of autoimmune diseases. IBM-BMT thus has several advantages: (i) no GvHD develops even if T cells are not depleted from BMCs; (ii) no graft failure occurs even if the dose of radiation as the conditioning regimen for allo BMT is reduced to 5Gy x 2; (iii) hemopoietic recovery is rapid; and (iv) the restoration of T-cell functions is quick and complete even in donor-recipient combinations across MHC barriers. We believe that these strategies for allo BMT and organ allografts herald a new era in transplantation, and that they would be helpful in allogeneic HSCT of autoimmune diseases.     

H-2 complementation in anti-H-Y cytotoxic T-cell responses can occur in chimeric mice.

Cytotoxic T-cell responses against the H-Y antigen in mice are under the control of major histocompatibility complex genes. Not only must cytotoxic T cells recognize both H-Y antigens and "self" H-2K/D molecules to lyse male target cells, but also "appropriate association" between H-Y antigens and H-2K/D antigens is required to induce such cytotoxic responses. Furthermore, it is suggested that appropriate association with H-2-I antigens may also be required to generate H-Y specific helper cells for the cytotoxic response. BALB/c(KdIdDd) mice are nonresponders against syngeneic H-Y antigens, because they lack appropriate associative H-2K/D antigens. This results in the failure of generation of anti H-Y cytotoxic cells, although helper cells may be induced. F1 hybrid mice (BALB/c X C3H/He)F1 or H-2 recombinant mice C3H-OH(KdIdDk) are responders, because H-2Dk (and H-2Kk in the F1) molecules offer appropriate association to H-Y antigens. We here report that allophenic chimeras (H-2d reversible H-2k) and irradiation bone marrow chimeras [H-2d + H-2k leads to F1(H-2d X H-2k)] generate anti-H-Y cytotoxic responses but that cells of the BALB/c(H-2d) genotype comprise most if not all of the cytotoxic cells. A working model is proposed to account for major histocompatibility complex control over anti-H-Y cytotoxic T-cell responses.     

New strategies for BMT and organ transplantation

Bone marrow transplantation (BMT) is now one of the most powerful strategies for the treatment of hematologic disorders (leukemia, aplastic anemia, etc), congenital immunodeficiencies, metabolic disorders, and also autoimmune diseases. Using various autoimmune-prone mice, we have previously shown that conventional allogeneic (allo) BMT can be used to treat a range of autoimmune diseases. We have very recently established new strategies for BMT and organ grafts. For BMT, to minimize the contamination of BMCs with T cells from the peripheral blood, we developed, using cynomolgus monkeys, a "Perfusion Method" to replace the conventional aspiration method for collecting bone marrow cells (BMCs). We injected the BMCs collected this way directly into the bone marrow cavity of recipients that had received fractionated irradiation (intra-bone marrow [IBM] injection). This "IBM-BMT" was found to be effective in treating autoimmune diseases in radiation-sensitive and chimeric-resistant MRL/lpr mice. in addition, this strategy was found to be applicable for the transplantation of organs, such as the skin and pancreas islets in mice and rats. We believe that these strategies for BMT and organ transplantation herald a new era in transplantation.