Histocompatibility Differences Research Articles

Comparison of wasting syndrome in [ [formula omitted]] chimera and graft versus host disease in [ [formula omitted]] chimera and an attempt to transfer the wasting syndrome in [ [formula omitted]] to MRL +/+ mice

We compared the findings in the wasting syndrome seen in [ MRL lpr lpr → MRL +/+ ] chimeras with those of chronic graft versus host disease (GVHD) in [ B10.D2 → BALB c ] chimeras. BALB c mice were lethally irradiated and administered B10.D2 spleen and bone marrow cells. These mice are identical to MHC and Mls but differ as to genetic background. As a result of chronic GVHD, these [ B10.D2 → BALB c ] chimeras showed hair loss, weight loss and atrophy of lymph nodes and spleen beginning 5 weeks after the transplantation. MRL lpr lpr mice carry the lpr gene and spontaneously develop generalized lymph node swelling and lupus-like autoimmune disease, while congenic MRL +/+ mice lack the lpr gene. The [ MRL lpr lpr → MRL +/+ ] chimeras showed wasting and the same symptoms as in [ B10.D2- BALB c ] chimeras beginnng 16 weeks after cell transfer. Skin biopsy from both chimeras showed very similar changes on HE staining and on immunoperoxidase staining for Ia and Thy-1. Our data suggest that very small differences in minor histocompatibility may induce GVHD which produces severe wasting with lethal consequences. Finally, we succeeded in transferring the wasting syndrome seen in the [ MRL lpr lpr → MRL +/+ ] chimera to other MRL +/+ mice by transplanting spleen cells from the [ MRL lpr lpr → MRL +/+ ] chimera to lethally irradiated MRL +/+ mice.

Graft rejection by T cells not restricted by conventional major histocompatibility complex molecules

The appropriate crosses of mice lacking conventional major histocompatibility complex (MHC) class I or class II molecules generate single- and double-deficient offspring. These were used as donors for skin grafts across major plus minor, or just minor, histocompatibility differences. Surprisingly, in the two circumstances, there was a rapid rejection of grafts lacking both MHC class I and class II molecules. Rejection was mediated by thymically derived CD4+ T cells of the host. We provide evidence that these T cells recognize an unconventional ligand, capable of activating a pre-formed T cell compartment but incapable of positively selecting it. The existence of this unexpected rejection phenomenon should serve to caution those aiming to engineer "universal donor" cells by simply abrogating expression of MHC class I and class II molecules.

Comparison of wasting syndrome in [ [formula omitted]] chimera and graft versus host disease in [ [formula omitted]] chimera and an attempt to transfer the wasting syndrome in [ [formula omitted]] chimera to MRL+/+ mice

Abstract We compared the findings in the wasting syndrome seen in [ MRL lpr lpr → MRL +/+ ] chimeras with those of chronic graft versus host disease (GVHD) in [ B10.D2 → BALB c ] chimeras. BALB c mice were lethally irradiated and administered B10.D2 spleen and bone marrow cells. These mice are identical to MHC and Mls but differ as to genetic background. As a result of chronic GVHD, these [ B10.D2 → BALB c ] chimeras showed hair loss, weight loss and atrophy of lymph nodes and spleen beginning 5 weeks after the transplantation. MRL lpr lpr mice carry the lpr gene and spontaneously develop generalized lymph node swelling and lupus-like autoimmune disease, while congenic MRL +/+ mice lack the lpr gene. The [ MRL lpr lpr → MRL +/+ ] chimeras showed wasting and the same symptoms as in [ B10.D2- BALB c ] chimeras beginnng 16 weeks after cell transfer. Skin biopsy from both chimeras showed very similar changes on HE staining and on immunoperoxidase staining for Ia and Thy-1. Our data suggest that very small differences in minor histocompatibility may induce GVHD which produces severe wasting with lethal consequences. Finally, we succeeded in transferring the wasting syndrome seen in the [ MRL lpr lpr → MRL +/+ ] chimera to other MRL +/+ mice by transplanting spleen cells from the [ MRL lpr lpr → MRL +/+ ] chimera to lethally irradiated MRL +/+ mice.

Histocompatibility in in vitro fertilization couples

Major histocompatibility differences between mother and fetus may facilitate implantation and maintenance of pregnancy. Thus, we have investigated the compatibility of HLAs in couples with three successive failed IVF-ET cycles. The study couples (n = 15) shared a statistically greater number of HLAs than IVF couples achieving a viable pregnancy with their first IVF-ET attempt (n = 15) and a control group of 100 fertile couples. No difference between fertile and infertile control couples was observed regarding HLA sharing. Thus, we conclude that some cases of unsuccessful ETs after IVF might be caused by underlying close histocompatibility between partners.

Prolongation of second heart transplants in rats.

Second clinical kidney grafts often survive longer than first grafts. Using a rat cardiac allograft model, we examined the conditions under which survival of a second graft can be longer than first graft survival. In the BUF-to-LEW combination, following rejection of the first transplant, second cardiac allografts from the same donor strain implanted immediately survived longer than the first grafts (P = 0.047). Although the mean survival time of first grafts was 9.0 days, second grafts implanted in the same animals survived 19.5 days. In contrast, when ACI donors were used for the same LEW recipients, the second grafts were rejected in 3 days compared with 6.6 days for first grafts. Donor-specific spleen cell transfusions in these combinations resulted in prolonged survival in the BUF to LEW combination, but had no effect when the donor strain was ACI. Second grafts from BUF had prolonged survival following rejection of the first graft. Thus the histocompatibility difference was a determining factor of whether or not prolongation would be obtained. Another factor was timing of the second transplant. If 7 days were allowed to elapse following rejection of the first graft before implantation of the second, the enhancement effect was lost. Moreover, in the LEW-to-ACI combination in which second grafts were rejected rapidly, removal of the first graft after 7 days (before rejection), resulted in prolonged survival of the second graft. There is, therefore, a window of time before rejection of first grafts and shortly thereafter, when the enhancement effect can be obtained. Passive transfer of serum in the BUF-to-LEW combination resulted in enhancement, but transfer of splenic cells was ineffective. We conclude that graft rejection can result in induction of enhancement during a specific period, after which this effect is lost; and that enhancement can be obtained only in certain strain combinations. This suggests that human patients with heart transplants that reject might benefit from a second graft, even from a donor with a mismatch similar to the first graft.

Skin allograft rejection.

Skin allograft rejection is a test of the competence of T lymphocytes to mediate in vivo tissue destruction, which in turn reflects their role in critical functions such as anti-viral and tumor immunity. The tail-skin graft procedure described here is useful predominantly because of the ease of preparation and resistance to ischemic (nonspecific) necrosis. Additionally, it is not necessary to sacrifice the donor mouse. However, rejection of tail-skin grafts should not be used to test for genetic homogeneity in breeding experiments or to detect minor histocompatibility (minor-H) antigens because tail skin is less sensitive than trunk skin in detecting such differences. The trunk-skin graft procedure detailed here more difficult to perform than the tail-skin graft. It requires extensive tissue preparation and is more susceptible to ischemic necrosis. Trunk-skin grafts are especially useful for detecting minimal histocompatibility differences.

The impact of the UNOS mandatory sharing policy on recipients of the black and white races--experience at a single renal transplant center.

The impact of the United Network for Organ Sharing mandatory sharing policy on a large transplant center procuring kidneys primarily from caucasians while serving a pool of prospective recipients composed mainly of blacks is described. This policy requires that all 6-antigen-matched and phenotypically identical donor kidneys be shipped to the appropriately matched recipients. The study consisted of 49 kidneys from 25 cadaveric donors; one kidney was unusable. In general, the 33 recipients of the mandatorily shared kidneys were caucasian (94%), unsensitized (70%), and first-time transplants (73%). Allograft survival for the 24 first-time recipients was 100% (mean graft survival = 11.3 months). Of the 9 regraft kidneys, 2 have failed (mean graft survival = 11.9 months) due to chronic rejection. In comparison, the 16 paired kidneys transplanted into non-6-antigen-matched recipients exhibited a 1-year graft survival of 80% versus 92% for the 33 recipients of mandatorily shared kidneys (P = 0.01). These 16 recipients were composed of more blacks (38%), fewer regrafts (6%), and most were unsensitized (75%). All 25 cadaveric donors were caucasians with very common HLA types. Thus, kidneys provided by the UNOS mandatory sharing policy had excellent allograft survival, and the recipients were largely unsensitized caucasians receiving their first kidney. The low number of blacks receiving allografts under this policy may be due to two factors. First, the histocompatibility differences between black recipients and the primarily caucasian cadaveric donor pool limit the number of kidneys available to blacks. Secondly, blacks do not have access to the best-matched kidneys, in part due to few black donors, their best source for well-matched kidneys. Thus, the mandatory sharing program is of clear benefit to the recipients of these well-matched kidneys; however, for a local program servicing a waiting list composed of 64% blacks the policy has been of limited value. In contrast, over 50% of local cadaveric transplants are into black recipients in a waiting time of 197 days, one third the national average for blacks. In conclusion, this study supports efforts to improve graft survival through matching but emphasizes the need to broaden our efforts in all areas of research and organ procurement to serve the entire recipient population, regardless of race.

Transfer of long-lasting tumor immunity by immune T cells from MHC congenic mice: Migration, survival and tumor-protectivity of cytotoxic donor cells

Immunocompetent B10.D2 (H-2d) mice are able to reject the highly malignant lymphoma ESb of DBA/2 (H-2d) origin very effectively. Seven days after intravenous injection of the ESb tumor cells, B10.D2 mice developed a strong tumor-rejection response which was associated with the generation of anti-tumor T cells in their spleens with direct cytotoxic activity. Most of the cytotoxic potential was directed against the minor histocompatibility differences as demonstrated by the lysis of unrelated DBA/2 derived Eb tumor cells and normal DBA/2 but no B10.D2 derived ConA lymphoblasts. A previously performed clonal analysis, however, revealed a minority population of CTL clones which specifically recognized the ESb specific transplantation antigen (ESb-TATA). When transferred systemically into DBA/2 mice, the B10.D2 anti-ESb immune spleen cells could delay the outgrowth of s.c. transplanted ESb tumor cells. When the ESb tumor cells were experimentally distributed in a s.c. implanted sponge-matrix, the i.v. injected B10.D2 immune cells could confer complete protective immunity against the metastatic tumor, provided the recipients were pre-treated with 5 Gy to allow a better take of the allogeneic cells. The distribution of intravenously injected B10.D2 donor spleen cells was assessed in the recipients up to 50 days by cytotoxicity testing and assaying for the expression of the beta 2 microglobulin allelic form b (beta 2mb). These tests revealed a high propensity of donor cells to populate the spleen and lymph nodes of the DBA/2 recipients. Again this was particularly marked in sublethally irradiated mice where a long-lasting lymphoid chimerism was established.

Mechanisms of graft failure after human marrow transplantation: a review

Graft failure (GF) following bone marrow transplantation (BMT) in man is usually attributed to allograft rejection; however, other mechanisms of GF exist. Exposure of the developing allograft to viruses, myelotoxic drugs, and damage to the host-derived marrow stroma during graft-versus-host disease (GVHD) may all cause GF. Later, in the posttransplant course, recurrence of the original disease may ultimately destroy or replace the graft. Overall allogeneic rejection remains the most important cause of GF and most in vivo and in vitro evidence points to a T cell mechanism. The incidence of rejection after clinical BMT is very variable and highly dependent on HLA and non HLA histocompatibility differences between donor and recipient, the level of recipient sensitisation pre-BMT and the immunosuppressive protocols used pre-transplant and for the prevention of GVHD.

Specific manipulation in vivo of immunity to skin grafts bearing multiple minor histocompatibility differences

Naive CBA mice injected with AKR spleen cells via the portal vein (p.v.) subsequently showed decreased stimulation in vitro in a primary MLR or cell-mediated lympholysis assay with irradiated AKR stimulator cells. No inhibition of stimulation by B10.BR cells is seen. These mice also show specific prolongation of survival of AKR skin grafts in vivo and diminished capacity for in vivo priming for (secondary) anti-AKR responses in vitro. These effects are not seen if initial challenge is with AKR cells injected subcutaneously (s.c.) or via the lateral tail vein (i.v.). Moreover, if immune CBA anti-AKR mice are similarly challenged with AKR cells via the portal vein, no suppression of anti-AKR immunity is elicited, as determined by subsequent in vitro assays or in vivo graft rejection. However, spleen cells from CBA anti-AKR immune mice can be used to induce, in further naive CBA mice, a specific suppression of subsequent anti-AKR graft reactivity (assayed in vitro or in vivo). Active T cell-mediated suppression can be documented using both these protocols though the additional involvement of specific serum-mediated suppression cannot be eliminated.

Nerve graft immunogenicity as a factor determining axonal regeneration in the rat

Acellular basal lamina grafts have recently been reported to support axonal regeneration and have been used in peripheral nerve repair. The present study was designed to determine the immunogenicity of such basal lamina allografts (grafts that are genetically different) and their potential as bridging material for nerve gap repair. Inbred strains of Fischer and Buffalo rats with known histocompatibility differences were used. Acellular grafts were prepared by repeated freezing and thawing nerve tissue predegenerated in situ for 6 weeks. Non-frozen predegenerated nerves were used as cellular grafts for comparison. Fischer rats were used as hosts and received cellular or acellular grafts obtained from Fischer (isograft, genetically identical) or Buffalo (allograft) donors. The grafts were evaluated morphologically at 1, 2, 4, and 12 weeks after transplantation. The cellular isografts supported axonal regeneration best. The cellular allografts were invariably rejected and were unsuccessful or only partially successful in supporting regeneration. In contrast, acellular allografts, in spite of their mild immunogenicity were successful in supporting regeneration, as were the acellular isografts. The rate of host axonal regeneration and recovery of target muscle was reduced in acellular allografts and isografts as compared to cellular isografts. It is concluded that acellular allografts are suitable for supporting axonal regeneration and may be used to bridge gaps in injured peripheral nerves.

Graft-versus-host disease: an alternative hypothesis

Medawar and Billingham in their classic experiments described three prerequisites for the development of graft-versus-host disease (GVHD): first, the presence of immunocompetent cells in the donor inoculum; second, the inability of the recipient to reject the donor cells; and third, a histocompatibility difference between the donor and recipient. These experiments are the basis for all later hypotheses related to the pathogenesis of GVHD. Recently, de Gast and colleagues reviewed the role of environmental antigens in the pathogenesis of GVHD and suggested that immunological responses to environmental antigens by the transplanted donor cells might contribute to an increased donor anti-recipient response. An area not addressed in that review was the potential role of autoreactivity in GVHD. In this short article, Robertson Parkman highlights the role of autoreactivity and autoantigens in the pathogenesis of both acute and chronic GVHD in histocompatible bone marrow transplantation.

Antibody-Mediated Marrow Failure After Allogeneic Bone Marrow Transplantation

Marrow graft failure observed in association with histocompatibility differences between donor and recipient is often attributed to rejection mediated by host-derived cytolytic T lymphocytes. The data presented in this report indicate that persistent host antibodies specific for donor antigen may also mediate graft failure, either by antibody-dependent cell-mediated cytotoxicity (ADCC), or complement-mediated cytotoxicity. In the case of HLA Class I disparity, where all donor cells express the target antigen, the presence of alpha-donor antibody was associated with complete graft failure and death. In the case of ABO blood group antigen disparity, the presence of alpha-donor antibody resulted in erythroid hypoplasia. The latter cases proved informative insofar as they established that host antibodies could persist for more than 18 months after chemoradiotherapy and impair marrow function.

Antibody-mediated marrow failure after allogeneic bone marrow transplantation

Marrow graft failure observed in association with histocompatibility differences between donor and recipient is often attributed to rejection mediated by host-derived cytolytic T lymphocytes. The data presented in this report indicate that persistent host antibodies specific for donor antigen may also mediate graft failure, either by antibody-dependent cell-mediated cytotoxicity (ADCC), or complement- mediated cytotoxicity. In the case of HLA Class I disparity, where all donor cells express the target antigen, the presence of alpha-donor antibody was associated with complete graft failure and death. In the case of ABO blood group antigen disparity, the presence of alpha-donor antibody resulted in erythroid hypoplasia. The latter cases proved informative insofar as they established that host antibodies could persist for more than 18 months after chemoradiotherapy and impair marrow function.

Cardiac transplantation in the rat. I. The effect of histocompatibility differences on graft arteriosclerosis.

The development of arteriosclerosis is the most serious and common complication in long-term survivors of cardiac transplantation. We have used a variety of inbred rat strains with selected histocompatibility differences to examine the influence of prolonged, mild rejection reactions on the development of pathological changes in long-term cardiac allografts. Heterotopic cardiac allografts were exchanged between rat strains that differed for MHC class I (RT1.A and/or RT1.E) antigens or groups of minor, non-MHC antigens in MHC-compatible congenic combinations. Our results demonstrate that in strain combinations in which the allograft reaction is mild and prolonged, the donor hearts exhibit pathological changes that include a diffuse, interstitial myocardial fibrosis, perivascular fibrosis, and intimal proliferation in arteries of the graft myocardium. The lesions were less prominent in animals with more active rejection and infrequent in strains that differ for class I histocompatibility antigens or syngeneic controls. These results suggest that the comparable pathological changes seen in long-term human cardiac survivors may reflect low-level, persistent allograft reactions rather than factors associated with graft anoxia or effects of immunotherapy to prevent graft rejection.

Chapter 13 Neural transplantation of horseradish peroxidase-labeled hippocampal cell suspensions in an experimental model of cerebral ischemia

Publisher Summary One of the major obstacles in assessing the use of neuronal transplants to replace cells that are lost because of ischemia is the inability to identify and distinguish homotypically-transplanted cells from similar cells in the host brain. This chapter discusses the use of horseradish peroxidase (HRP) to label cell suspensions of fetal rodent hippocampus that were injected into the hippocampi of post-ischemic rats to determine whether homotypically transplanted cells could be distinguished from those of the host. When homotypic cells are to be transplanted and are labeled with HRP, a label is required, which might help in distinguishing cells of transplant origin from those of the host. One factor influencing the transplant survival appears to be the placement of the cells within the hippocampus. Whether the minor differences in histocompatibility between the donor tissue and host in combination with the cytotoxicity factors influence cellular survival is an issue that remains to be resolved. The chapter suggests that neural transplantation may be feasible for treatment for focal lesions produced during ischemia. Sufficient cell growth and development that occurred in the four vessel occlusion (VO) animals, justify further transplantation experiments in this model.

Murine Peyer's patches are capable of generating a cytotoxic T cell (CTL) response to nominal antigens.

The experiments described in this report were designed to determine whether murine Peyer’s patches are capable of generating a cytotoxic T cell (CTL) response to nominal (non-MHC encoded) antigens. To date, Kagnoff (1) is the only researcher who has been able to directly demonstrate CTL activity in Peyer’s patches. He demonstrated that a cytotoxic T cell response could be detected in Peyer’s patches from mice chronically fed tumor cells that were mismatched at the major histocompatibility locus. However, he was unable to demonstrate a similar response in Peyer’s patches when mice were chronically fed tumor cells bearing minor histocompatibility differences. While his study demonstrated that a CTL response could occur in Peyer’s patches, the generation of allospecific CTL’s, whose precursors are present at high frequency among normal T cells (2), may not be representative of the potential of Peyer’s patches to generate CTL activity directed to nominal antigens. We have utilized reovirus serotype 1 (reo 1) as a model nominal antigen to determine whether intraduodenally applied virus induces a detectable CTL response in murine Peyer’s patches.

The Depletion of T Cell Subsets in Vitro and in Vivo

One of the major complications of allogeneic bone marrow transplantation is graft-versus-host disease. This can be avoided by removing the mature T cells from the marrow, most conveniently by the use of monoclonal antibodies. However, T cell purging results in an increased tendency for the recipient to reject the donor marrow. We have developed monoclonal antibodies to L3/T4 and Lyt-2 that specifically deplete functional T cell subsets in mice. We demonstrate that such reagents can be used to control both graft-versus-host disease and marrow rejection in mouse models of bone marrow transplantation across one-haplotype or two-haplotype major histocompatibility differences. Such strategies to abrogate host resistance, by administration of anti-T-cell monoclonal antibodies to the recipient, may complement marrow T cell purging for human allogeneic bone marrow transplantation.

Current trends in histocompatibility: Clinical relevance versus laboratory phenomena

The role of conventionally analyzed data in tissue typing is decreasing in clinical transplantation. Improved immunosuppression seems increasingly capable of overcoming the immune response to known histocompatibility differences. The introduction of the concept of public specificities may improve the correlation between matching and graft outcome. The further understanding of the roles of cell-specific antigen systems, particularly those on the vascular endothelial cells, may also improve the clinical relevance of matching. The VEC antigens are becoming more important both in our understanding of histocompatibility and of sensitization. The sensitization of potential transplant candidates needs to be prevented by new protocols for transfusion. The amelioration of sensitization to histocompatibility antigens similar to that achieved in transplantation across the ABO barrier seems theoretically possible and should be an important research effort. Most importantly, sensitization needs to be more accurately defined. Sensitization to specific antigens (cell-specific as well as HLA) must be more carefully correlated with graft survival, and the quantitative aspects of sensitization must be better understood. Thus, there are new trends in the field of histocompatibility that hold promise for further improving the results of clinical transplantation and our understanding of the rejection process.

Monoclonal T cell responses to two epitopes on a single immunogen controlled by two distinct genes.

The fine specificities of immune T cells were studied in a system in which the response to the antigen can involve two immune response (Ir) genes and two epitopes on a single synthetic polypeptide immunogen. The (BALB/c X SJL)F1 (H-2d X H-2s) mice can respond to the random terpolymer poly(Glu55, Lys36, Phe9) (GLPhe) through the H-2d-linked Ir gene (Ir-d) or through the complementing Ir gene (Ir-dxs), which controls the immune response to poly(Glu, Phe), epitopes that are present in GLPhe. Nine groups of monoclonal T cells were obtained from (H-2d X H-2s)F1 mice immunized with GLPhe. These groups were delineated by the differences in major histocompatibility (MHC) restriction on antigen-presenting cells (APC) and the cross-reactions with GPhe or GLT. A unique T cell line was discovered that can react to the three polymers (GLPhe, GLT, GPhe) even though GLT and GPhe immune T cells do not normally show reciprocal cross-reactions. The monoclonal T cells retain helper activities in the Mishell-Dutton culture. Although the activation of T cells is antigen specific and MHC restricted, the subsequent B cell response is nonspecific.