A study on graft-versus-host reaction (GVHR) by Simonsen's splenomegaly assay. Cells and antigen systems involved in induction of GVHR

Cells and histocompatibility antigen systems involved in graft-versus-host reactions (GVHR) were analyzed using Simonsen's splenomegaly assay employing various combinations of donor and F1 hybrid recipients mice. Most of the cells proliferating in spleens of mice undergoing GVHR were J11d+, and had histological features of cells of the hematopoietic lineage. The proportions of CD3+ T cells were decreased in the spleens. Disparity at minor histocompatibility determinants of AKR, I-E and H-2D regions between B10.A(4R) donors and (4R X AKR) F1 recipients evoked only negligible GVHR. On the contrary, disparity at H-2K and/or I-A regions appeared to be sufficient to permit induction of full GVHR. When surface markers of donor spleen cells were analyzed, it was shown that Thy-1+ and/or MEL-14+ cells caused a strong effect on GVHR. Further, either CD4+ or CD8+ T cell subset could induce significant GVHR. However, synergistic influences of these two T cell subsets on one another in GVHR were observed. The present results raise the possibility of using Simonsen's assay along with a number of reagents to identify the contribution of subsets of T lymphocytes and in analyzing precise contributions of cellular components from both donor and recipient, and also of the target antigen systems of the recipient that contribute to early events involved in GVHR.     

Glomerulopathy induced by graft-versus-host reaction in the rat. Requirement of donor CD4+ T lymphocytes and MHC class II incompatibility at the lymphoid compartment.

Graft-versus-host reactions (GVHR) can be associated with several autoimmune phenomena involving the kidney as a target organ. By transferring lymphocytes of AO rats into complete Freund's adjuvant-pretreated (AO x BN)F1 hybrids, a dose-dependent GVHR with glomerulopathy was experimentally induced. IgM, IgG1, and IgG2a were deposited in the mesangial area and along the glomerular basement membrane. Eluted immunoglobulins from diseased kidneys bound to normal basement membranes and especially to laminin. Anti-laminin reactivity was also present in sera from F1 recipients with GVHR. Parental CD4+ T lymphocytes were required and sufficient to induce GVHR and glomerulopathy in sublethally irradiated F1 hybrids. Using various F1 hybrids, MHC class II incompatibility was shown to be required for the induction of GVHR-associated glomerulopathy. Across MHC class I incompatibility, GVHR without glomerulopathy could be induced, provided that both CD4+ and CD8+ donor T lymphocytes were administered. Finally, MHC incompatibility between donor T lymphocytes and the recipient non-lymphoid compartment was found to be sufficient for the induction of GVHR, but not for GVHR-associated glomerulopathy. The results indicate that alloreactive donor CD4+ T lymphocytes have to interact directly with MHC class II alloantigen bearing host B lymphocytes in order to stimulate the latter to produce (auto-)antibodies. GVHR-induced glomerulopathy shares several immunopathological features with HgCl2-induced autoimmune glomerulopathy in the rat.     

A Study on Graft-versus-Host Reaction (GVHR) by Simonsen's Splenomegaly Assay Cells and Antigen Systems Involved in Induction of GVHR

Cells and histocompatibility antigen systems involved in graft-versus-host reactions (GVHR) were analyzed using Simonsen's splenomegaly assay employing various combinations of donor and F₁ hybrid recipients mice. Most of the cells proliferating in spleens of mice undergoing GVHR were J11d⁺, and had histological features of cells of the hematopoietic lineage. The proportions of CD3⁺ T cells were decreased in the spleens. Disparity at minor histocompatibility determinants of AKR, I-E and H-2D regions between B10.A(4R) donors and (4R × AKR) F₁ recipients evoked only negligible GVHR. On the contrary, disparity at H-2K and/or I-A regions appeared to be sufficient to permit induction of full GVHR. When surface markers of donor spleen cells were analyzed, it was shown that Thy-1⁺ and/or MEL-14⁺ cells caused a strong effect on GVHR. Further, either CD4⁺ or CD8⁺ T cell subset could induce significant GVHR. However, synergistic influences of these two T cell subsets on one another in GVHR were observed. The present results raise the possibility of using Simonsen's assay along with a number of reagents to identify the contribution of subsets of T lymphocytes and in analyzing precise contributions of cellular components from both donor and recipient, and also of the target antigen systems of the recipient that contribute to early events involved in GVHR.     

Donor and recipient specific tolerance in cells from semi-allogeneic, H-2 subregion compatible or fully allogeneic bone marrow chimeras attributable to clonal deletion

Specificities of tolerance induced in allogeneic bone marrow (BM) chimeras which had been established by injecting allogeneic BM cells pretreated with anti-Thy-1 mAb alone (without complement (C)) were analyzed using Simonsen's splenomegaly assay. Lymphocytes from fully allogeneic, semi-allogeneic and H-2 subregion compatible BM chimeras were specifically unresponsive to donor and recipient antigens (Ag). However, cells from H-2 subregion compatible chimeras initiated as vigorously a GVHR in F1 recipient mice, which were disparate at H-2K and I-A regions, as did spleen cells of donor mice, which were incompatible at the entire H-2 and minor histocompatibility regions of the recipients. The donor cells from such chimeras that initiated these considerable GVHR were either CD4+ or CD8+ T cells. Furthermore, synergistic effects by the CD4+ and CD8+ T lymphocytes were also observed. We found no evidence for a suppressive mechanism(s) in maintenance of the specific tolerance in allogeneic chimeras. Further, when lymphoid cells from these chimeras were adoptively transferred to irradiated mice of the donor strain and maintained for 5 days in the absence of recipient Ag (tolerogen), the adoptively transferred cells were shown to retain their unresponsiveness to the recipient Ag. These results reveal that T lymphocytes from allogeneic BM chimeras prepared by our method had been specifically induced to a tolerant state to both donor and recipient Ag and that the major mechanism of induction and maintenance of long-lasting tolerance is attributable to clonal deletion of both CD4+ and CD8+ T cell subsets rather than to the development of a population of suppressor cells of any sort.     

Hyper IgE in stimulatory graft-versus-host disease: role of interleukin-4.

Intravenous injection of 2 x 10(8) DBA/2 spleen cells into adult intact (C57BL/6 x DBA/2) F1 mice results in a stimulatory graft-versus-host reaction (GVHR) linked to the recognition by donor CD4+ T cells of Ia alloantigens on host B cells. In the experiments presented here, we found that this GVHR is associated with a major increase in IgE serum levels which was already present 7 days after the cell transfer. At 6 weeks, mean IgE levels were more than 200-fold above the control values. Host B cells were responsible for the hypersecretion of IgE in stimulatory GVHR since it was also observed when the DBA/2 donor inoculum was depleted of B cells but not when the F1 recipients were irradiated. The induction of IgE secretion required donor CD4+ T cells as treatment of the donor inoculum with lytic anti-CD4 monoclonal antibody (MoAb) completely prevented the occurrence of the hyper IgE whereas depletion of CD8+ cells had no influence on this parameter. The role played by interleukin-4 (IL-4) in this model was analysed in vivo by the administration of the 11B11 anti-IL-4 rat MoAb (total dose 36 mg) during the first 12 days following induction of stimulatory GVHR by 8 x 10(7) DBA/2 spleen cells. This treatment completely prevented the development of hyper IgE whereas the administration of a control rat MoAb had no significant effect. We conclude that stimulatory GVHR in mice is associated with a major increase in serum IgE which is mediated by IL-4.     

Unexpected role of TNF-alpha in graft versus host reaction (GVHR): donor-derived TNF-alpha suppresses GVHR via inhibition of IFN-gamma-dependent donor type-1 immunity

Graft versus host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation, leading to significant morbidity and mortality. Host-derived TNF-alpha play a role in the induction of allo-reactive donor T cell activation and the pathogenesis of GVHD. On the other hand, the precise role of donor-derived TNF-alpha in GVHD remains unclear. To elucidate this issue, we designed an acute GVHD model using (B6 x D2) F1 recipient mice transferred with spleen cells derived from either wild-type or TNF-alpha(-/-) C57BL/6 mice. Surprisingly, we found that spleen cells from TNF-alpha(-/-) mice induce more severe graft versus host reaction (GVHR) than wild-type spleen cells upon transfer into B6D2F1 mice. Transplantation of TNF-alpha(-/-) mouse spleen cells was associated with enhanced anti-host CTL generation and augmented deletion of host cells. Moreover, mice receiving TNF-alpha(-/-) cells showed significantly higher levels of serum IFN-gamma, which was mainly produced by donor CD8+ T cells. We also demonstrated that TNF-alpha deficiency in donor spleen cells caused a marked elevation of TNF-alpha producing capacity by LPS-stimulated host macrophages. Such enhanced GVHR was completely prevented by using TNF-alpha(-/-)IFN-gamma(-/-) splenic cells. Our findings demonstrate, for the first time, that donor-derived TNF-alpha suppress GVHR by inhibiting IFN-gamma-dependent donor type-1 immunity which is essential for host TNF-alpha elevation.     

Cellular immune reactions against pancreatic islets as a consequence of graft versus host disease.

We studied autoimmune reactions against pancreatic islets occurring as a consequence of defects of the immune system rather than after pathological changes in the endocrine organ itself. Immune dysregulation was induced by transfer of parental lymphocytes into semi-allogeneic F1 recipient mice (graft versus host reaction, GVHR). Recipients were killed 1 month after the induction of the disease. Pancreatic islets were screened by light microscopy for signs of lymphocytic infiltration (insulitis). Severe insulitis was found in all mice undergoing GVHR. The cytotoxic activity of lymphocytes was apparent in electron microscopic studies and affected only B cells. Infiltrations were not seen in the exocrine part of the pancreas nor in heart, liver or kidneys at this early stage of GVHR. It is concluded that non-specific disorders of the immune system induced by GVHR may lead to specific cellular autoimmune reactions against B cells of pancreatic islets.     

Persistence of allospecific helper T cells is required for maintaining autoantibody formation in lupus-like graft-versus-host disease

Induction of a graft-versus-host (GVH) reaction (GVHR) in non-irradiated (C57BL/10ScSn x DBA/2)F1 mice (BDF1) with DBA/2 lymphoid cells leads to chronic GVH disease (GVHD). One of the pathological alterations of this type of GVHD is hyperplasia of host B cells with production of lupus-like autoantibodies. This hyperstimulation of host B cells has previously been demonstrated to be induced by alloreactive donor T helper cells that were also proposed to maintain it. We provide three pieces of experimental evidence in support of this concept. First, treatment of mice with chronic GVHD by injection of monoclonal anti-Thy-1.2 antibodies, performed at week 6 after the injection of C57BL/6 lymphoid cells into (C57BL/6 x C57BL.bm12)F1 mice led to a significant decrease in the titre of anti-nuclear antibodies. Second, CD4+ donor T cells persisted in BDF1 mice with GVHD (GVHF1) for at least 10 weeks after the induction of GVHR; these T cells showed alloreactive helper activity against H-2b MHC determinants of the opposite parent in vitro. Third, T cells of GVHF1 mice, obtained 2 months after the induction of GVHR and transferred into normal secondary recipients, induced signs of chronic GVHD in DBF1 but not in DBA/2 mice. The combined results show that persisting donor T helper cells in GVHF1 mice retain their alloreactivity towards H-2 class II antigens for a long time after the induction of GVHR and they strongly suggest that these T cells are also the driving force behind the production of lupus-like autoantibodies at the late stage of chronic GVHD.     

Hepatic lesions induced by graft-versus-host reaction across MHC class II antigens: an implication for animal model of primary biliary cirrhosis

To induce graft-versus-host reaction (GVHR), C57B1/6 (B6) spleen cells were injected into (B6 x bm1)F1, (B6 x bm12)F1, and (bm1 x bm12)F1 mice. Since the strains bm1 and bm12 are mutant at the H-2Kb and I-Ab regions of major histocompatibility complex (MHC), respectively, we can assess MHC class I- or class II-different GVHR. As reported earlier, immunological perturbations assessed by the number of immunoglobulin-producing cells and immune complex deposition in renal glomeruli were demonstrated in MHC class II-different GVHR. A conspicuous finding in this report is that epithelioid granuloma formation was observed in the portal area and around the central vein of liver of (B6 x bm12)F1 mice injected with B6 spleen cells. The epithelioid granuloma formation was not observed in (B6 x bm1)F1 nor (bm1 x bm12)F1 recipient mice. Degenerative changes resembling chronic nonsuppurative destructive cholangitis in primary biliary cirrhosis were also observed in the bile duct epithelium in (B6 x bm12)F1 and (bm1 x bm12)F1 mice. These lesions were already obvious at the 2 week postinjection of donor cells and were continuously observed up to 10 weeks when immunological perturbations subsided. Thus, class II-disparate GVHR in this experimental system might provide a novel animal model of protracted disease, primary biliary cirrhosis.     

Immunosuppressive activity of macrophages in mice undergoing graft-versus-host reaction due to major histocompatibility complex class I plus II difference.

In a previous report, we showed that the injection of parental CD4+ T cells into major histocompatibility complex (MHC) class II disparate F1 hybrid mice induces autoimmune-like graft versus-host reaction (GVHR) resembling systemic lupus erythematosus (SLE) and the hepatic lesion of primary biliary cirrhosis (PBC). In the present study, we examined whether or not simultaneous or subsequent injection of CD8+ T cells changes the GVHR form. When parental CD8+ T cells together with CD4+ T cells were injected into MHC class I plus class II-disparate F1 mice, autoimmune phenomena did not develop and alternatively a profound immunosuppressive state was induced. Furthermore, ongoing autoimmune-like GVHR induced by CD4+ T cells was also suppressed by later injection of CD8+ T cells. In these mice, an increase of donor type CD8+ T cells and a marked decrease of host B and T cells in the spleen were observed. The spleen cells from these mice strongly inhibited the mitogenic response of normal spleen cells against lipopolysaccharide (LPS). In vitro studies demonstrated that this immunosuppression was not induced by CD8+ T cells themselves but by macrophages which produced suppressive factor(s) by LPS stimulation. These findings were discussed with reference to suppressive mechanisms of GVHR.     

Experimental studies of immunologically mediated enteropathy. V. Destructive enteropathy during an acute graft-versus-host reaction in adult BDF1 mice.

As a means of investigating further the pathogenesis of intestinal immunopathology, we have attempted to produce a destructive enteropathy by inducing an acute graft-versus-host reaction (GVHR) in mature, immunocompetent mice. Adult (C57b1/10 X DBA/2)F1 (BDF1) mice given C57B1/10(B10) spleen cells develop a severe GVHR which is associated with marked weight loss and high mortality. In the intestine an initial phase of enteropathy characterized by intense crypt hyperplasia is replaced by more severe intestinal damage which includes villus atrophy and loss of intra-epithelial lymphocytes. These pathological alterations are paralleled by the generation of anti-host cytotoxic T lymphocytes (CTL), marked immunosuppression and the loss of natural killer (NK) cells. In contrast to these findings, adult BDF1 mice given DBA/2 donor cells do not develop an acute systemic GVHR and have no CTL or intestinal pathology, despite prolonged splenomegaly and enhanced NK cell activity. Thus, destructive enteropathy can be induced during a GVHR in intact hosts and our results confirm that this enteropathy has a biphasic pattern, with villus atrophy representing the progression of initial crypt hyperplasia in severe forms of disease associated with weight loss and specific CTL.     

Protection from lethal graft-vs.-host disease by donor stem cell repopulation.

Graft-vs.-host reaction (GVHR) induced in non-irradiated F1 mice with DBA/2J parental spleen and lymph node (LN) cells usually does not lead to acute GVH disease (GVHD). This contrasts with the GVHR induced in other parent-F1 combinations involving both major histocompatibility complex (MHC) class I and class II differences between donor and host. Most signs of acute GVHD in non-irradiated F1 mice relate to immunodeficiency following destruction of the lymphohemopoietic system of the host, which leads to wasting and death due to infections. This sequence of events is prevented when donor lymphoid cells, originating from grafted stem cells, repopulate the destroyed lymphohemopoietic system of the host. To examine whether a "silent" repopulation of the F1 host by donor stem cells might underly the absence of clinical signs of acute GVHD when GVHR is induced with DBA/2J lymphoid cells, GVHR was induced with LN cells, which do not contain stem cells. Indeed, GVHR induced in (C57BL/10 x DBA/2J)F1 (BDF1) mice with 80 x 10(6) DBA/2J LN cells led to acute GVHD. Signs of acute GVHD such as wasting and death did not occur when donor stem cells, from an inoculum of DBA/2J spleen and LN cells, were allowed to repopulate the lymphohemopoietic system of the host. The effect of donor stem cells on clinical signs of acute GVHD was more apparent when (B10.D2 x DBA/2J)F1, instead of DBA/2J, lymphoid cells were used to induce GVHR. The detection of alloreactive anti-host cytotoxic T lymphocyte (CTL) activity during acute GVHD induced with DBA/2J donor lymphoid cells supports the hypothesis that such CTL contribute to the destruction of the host immune system in acute GVHD.     

Lymphokine activity production in graft-versus-host reactions across minor histocompatibility antigen barriers.

Activated T cells responding to murine minor histocompatibility antigens (HA) were characterized according to the patterns of lymphokine activity production. Although B10.D2/nSN and BALB/c are mutually non-reactive in mixed lymphocyte reaction (MLR), graft-versus-host reaction (GVHR) can be induced by the injection of a large amount of B10.D2/nSN lymphoid cells into irradiated BALB/c recipient mice. Spleen cells from such GVHR mice spontaneously produced interleukin 3 (IL-3)-dependent cell-stimulating activity in cultures, but did not produce interleukin 2 (IL-2). Normal B10.D2/nSN spleen cells also produced IL-3-like activity, but not IL-2 in MLR supernatants, in response to irradiated BALB/c splenocytes. In addition, B-cell stimulatory factor-1 (BSF-1)/interleukin 4 (IL-4) and colony-stimulating factor (CSF) activity were detected in MLR supernatants. The properties of the produced lymphokine activities were similar to those produced in syngeneic transplant mice and syngeneic MLR, but a difference in the time course of lymphokine production existed between GVHR and syngeneic transplant mice. These results indicate that T cells may be activated in vivo in allogeneic transplantation when the donor and the recipient are matched for major HA, and are non-reactive in MLR. Also, the character of lymphokine-producing T cells activated by minor HA may not be qualitatively different from those responding to irradiated syngeneic cells.     

Pneumopathies of the graft-versus-host reaction. Alveolitis associated with an increased level of tumor necrosis factor mRNA and chronic interstitial pneumonitis

Irradiated (CBA x B10)F1 hybrid mice were injected with parental T lymphocyte-depleted bone marrow cells, (BMC), or with parental BMC together with T lymphocytes in an amount inducing greater than 80% mortality by day 40. Recipients of T cell depleted BMC did not show any mortality or significant pulmonary alterations, whereas recipients of BMC with T lymphocytes showed an alveolitis during the acute phase of the graft-versus-host reaction (GVHR) (day 15 to 25), characterized by: (a) alveolar hemorrhages, (b) increase of the number of alveolar leukocytes, (c) platelet microthrombi, (d) damage of the alveolar endothelial and epithelial cells, (e) increase of the turnover rate of the alveolar cells as shown by 3HTdR labelling, (f) increase in cell number and protein content of the bronchoalveolar lavage. These lesions were severe in the B10 versus F1, but absent in the reciprocal CBA versus F1 GVHR combination. The alveolitis was associated with a marked increase in the level of tumor necrosis factor-alpha mRNA, as shown by Northern gel analysis of lung RNA and was partially prevented by passive immunization with a rabbit anti-mouse tumor necrosis factor-alpha antibody. Mice examined after 25 days of evolution (i.e., chronic GVHR) presented an interstitial pneumonitis characterized by the accumulation of mononucleated cells, resembling large granular lymphocytes, which infiltrated first the intima of the blood vessels, and subsequently the interstice and the bronchi. These data demonstrate that the GVHR alone (in the absence of chemotherapy or overt infection) can induce two types of pneumopathies, an alveolitis and an interstitial pneumonitis.     

Activation of CD4+ and CD8+ lymphocyte subsets by streptozotocin in the popliteal lymph node assay. II. Comparison with acute graft-vs-host reaction in H-2 incompatible F1 mouse hybrids.

Changes in lymphocyte subsets during an acute GVH reaction were compared to STZ-induced PLN response in mice. The GVH reaction was induced locally by sc injection of parental C57Bl/6 [B6] spleen cells into (C57Bl/6 x DBA/2) F1 footpad [B6D2F1]. Early cell activation and time-related changes in T- and B-lymphocyte subsets were monitored during the onset of the GVH reaction by flow cytometry and immunophenotyping. Examination of cell size and chromatin decondensing for T- and B-cell subsets showed differences in activation profile during the early phase of the GVH reaction. The present study provides direct evidence for early in vivo activation of both CD4+ and CD8+ T-cells. Our data confirm the central role of T-cell activation in the induction of a GVH reaction and suggest that recirculatory host B-cells can play an important role in early GVH node enlargement. Overall, our comparative analysis supports the concept of polyclonal T-cell activation for both STZ-related and GVH-induced lymphoproliferation. Chemicals-induced lymphoproliferation leading to autoimmune reactions is a challenging issue. A number of drugs and chemicals have been tested in the PLNA assay for lymphoproliferative potential. We previously reported the activation and proliferation of T-cell subsets following STZ injection into murine footpads. The STZ-induced PLN enlargement and proliferation characteristics of T- and B-cell subsets were postulated to be similar to those of an acute allogeneic GVHR. In the present study, a cytometric analysis of T- and B-cell subsets in PLNs was performed during an acute allogeneic GVHR, for comparison purposes. Such a reaction results in a massive node enlargement five to ten times that seen after stimulation with conventional antigens. Acute GVHR is believed to be a direct consequence of the high frequency of alloreactive donor T-cells inducing a massive proliferation of B-cells, almost exclusively of host origin, in GVHR nodes. It is now widely accepted that donor T-cells activated as the result of exposure to foreign MHC antigens in the recipient, secrete various cytokines which assist the host B-cells and bypass the normal B-T cell cooperation. Induction of an acute GVHR, as in the parental B6--->recipient B6D2F1 model, requires the injection of CD4+ and CD8+ donor T-cells into an F1 recipient that differs from the parent at both MHC class I and II loci.(ABSTRACT TRUNCATED AT 400 WORDS)     

Depressed antibody responses to exogenous antigens in mice with lupus-like graft-versus-host disease

Previous work has established that a disease resembling systemic lupus erythematosus (SLE) can be induced in certain nonirradiated F1 mice undergoing a suitable graft-versus-host reaction (GVHR), e.g., (C57BL/10 X DBA/2)F1 mice injected with DBA/2 T cells. Here, we studied the antibody responses of such autoimmune graft-versus-host F1 mice to exogenous antigens, i.e., sheep erythrocytes, trinitrophenyl keyhole limpet hemocyanin, and levan. We found that primary antibody responses, in particular of IgG isotype, to the T-dependent antigens, sheep erythrocytes, and trinitrophenyl keyhole limpet hemocyanin were strongly suppressed during the entire observation period. Secondary anti-sheep erythrocyte responses, however, were normal, although the peak response was delayed for about 3 days. In contrast to the long-lasting depression of responses to T-dependent antigens, primary antibody responses to the T-independent antigen levan were depressed only at an early stage (i.e., week 2) of the graft-versus-host reaction. In spite of their depressed antibody responses to exogenous antigens, the graft-versus-host F1 mice showed increased numbers of spleen cells spontaneously secreting IgG, and produced IgG autoantibodies characteristic of systemic lupus erythematosus. Mixing experiments performed in vitro with cultures involving graft-versus-host spleen cells revealed that the decreased antibody formation cannot be attributed to suppressor T cells nor to a defect in helper T-cell function. Instead, the mechanism of decreased immune reactivity in SLE-like GVHR seems to operate at the level of B cells. Parallels between the decreased immune reactivity observed in lupus-like GVH disease and that described in human SLE as well as in spontaneously arising murine SLE are discussed.     

Persistence of anti-donor allohelper T cells after neonatal induction of allotolerance in mice

BALB/c mice rendered tolerant to A/J alloantigens by neonatal injection of 10(8) (A/J X BALB/c)F1 spleen cells develop an autoimmune disease associated with a polyclonal activation of donor B cells. To study the mechanisms leading to donor B cell activation in tolerant mice, we prepared mixed lymphocyte cultures (MLC) between splenic T cells from neonatally injected mice and donor-type (A/J X BALB/c)F1 or third-party (C57BL/6 X BALB/c)F1 B cells. T cells from tolerized mice were unable to generate cytotoxic T lymphocytes, to proliferate or to secrete interleukin (IL)2 after stimulation with donor alloantigens in MLC. These T cell responses were present after MLC with third-party antigens, but were of lower intensity than those generated by control BALB/c T cells. In contrast, T cells from tolerized mice stimulated immunoglobulin production by donor-type (A/J X BALB/c)F1 B cells much more powerfully than T cells from control BALB/c mice. The stimulation of donor-type (A/J X BALB/c)F1 B cells was polyclonal, as attested by the levels of anti-hapten and anti-DNA antibodies in the MLC supernatants. IgM was the dominant isotype secreted in vitro, but IgG1 and IgG3 were also produced in significant amounts. Lysis experiments indicated that the T cells responsible for F1 B cell stimulation in MLC were CD4+ host T cells. These T helper cells were alloreactive since they did not stimulate syngeneic BALB/c B cells, and their effect on donor B cells was specifically blocked by anti-donor Ia monoclonal antibodies. Addition of anti-IL 4 monoclonal antibody to MLC between T cells from tolerant mice and (A/J X BALB/c)F1 B cells almost completely abolished the production of IgG1, but not that of IgM or IgG3. Taken together, these findings indicate that neonatal injection of alloantigens in BALB/c mice induces a state of dissociated tolerance, with unresponsiveness of anti-donor T cells secreting IL 2 on the one hand, and persistence of T cells responsible for B cell help and IL 4 secretion on the other hand.     

Microheterogeneity in regulatory circuits for T-cell alloresponsiveness.

Mixed leucocyte cultures of responder spleen cells from individual B10 mice, challenged with irradiated allogeneic B10.D2 or B10.BR spleen cells, were used to generate discrete pools of cytotoxic T lymphocytes (CTL) with which to immunize (B10 x B10.D2)F1 or (B10 x B10.BR)F1 animals. Aliquots of the original donor B10 spleen cells were stored at -70 degrees. Eighteen days after immunization of the F1 animals, spleen and serum preparations from these mice were tested, in reciprocal fashion, for their ability to affect the development of CTL from the thawed donor B10 spleen lymphocytes in fresh cultures challenged with either the original or a third party allogeneic stimulus. Evidence for individual specific suppression by F1-T lymphocytes or by F1-serum (antibody) molecules was obtained. By priming (B10 x B10.D2)F1 mice with B10 lymphoid cells the F1 animals can also be shown to resist the otherwise lethal GvHD induced by sublethal whole body irradiation followed by intravenous challenge with B10 lymphoid cells. Using F1 mice primed and subsequently challenged with lymphocytes prepared from individual donors, self-preference in the regulation of GvHD was also seen. A similar fine specificity of regulatory cells was observed using suppressor cells from individual mice rendered neonatally tolerant of histocompatible cells (by inoculation of F1 hybrid cells within 24 hr of birth). These findings suggest that the mouse T cell alloreceptor repertoire is subject to a process of somatic diversification during normal ontogenesis. By examining the regulation of alloresponsiveness in T lymphocytes of B10.Br origin which differentiate from the appropriate stem cells in a B10 or B10.Br host, we have uncovered evidence that the T-cell alloreceptor repertoire is, in part at least, determined by the host MHC environment.     

Antibodies to IFN-gamma prevent immunologically mediated intestinal damage in murine graft-versus-host reaction.

We have tested the hypothesis that interferon-gamma (IFN-gamma) plays a role in the enteropathy of graft-versus-host reaction (GVHR) by treating host mice with a monoclonal antibody directed at this mediator. Two models of GVHR were examined. In the mild proliferative GVHR, which occurs in adult unirradiated (CBA x BALB/c)F1 mice given parental spleen cells, anti-IFN-gamma slightly inhibited the development of splenomegaly and the activation of natural killer (NK) cells in GVHR. Anti-IFN-gamma had no effect on splenomegaly or generation of anti-host cytotoxic T lymphocytes (CTL) during the more severe GVHR in adult BDF hosts, but inhibited the weight loss and mortality normally found in this GVHR. Despite these variable effects on systemic GVHR, anti-IFN-gamma treatment abolished the crypt hyperplasia and increased counts of intraepithelial lymphocytes (IEL) normally found in the jejunum of (CBA X BALB/c)F1 mice with GVHR. In parallel, anti-IFN-gamma-treated BDF1 mice with GVHR did not develop the villus atrophy and intense crypt hyperplasia found in untreated GVHR hosts. These results support the view that IFN-gamma is essential for the development of enteropathy in GVHR and we propose that this mediator may also be involved in the pathogenesis of clinical enteropathies in man.     

The IgG antibody reactivity of sera from patients with active chronic hepatitis to a crude liver antigen and liver specific protein (LSP): analysis by ELISA and immunoblotting.

This report extends our previous study on experimental autoimmune hepatitis in C57BL/6(B6) mice. Cellular immunity involved in the induction of liver injury in this model was studied by transfer of primed spleen cells from hepatitis donor mice to syngeneic normal recipient mice. The most prominent liver damage in recipient B6 mice was induced by transfer of nylon wool adherent spleen cells from hepatitis donor mice, and T cells in this fraction were the essential requirement for the liver damage in the recipient mice. Nylon wool adherent spleen cells from hepatitis donor mice after depletion of the suppressor T-cell function by low-dose (300 rad) irradiation induced more severe liver injury compared to the same cells without irradiation. When the recipient mice were depleted of lymphocytes by low or high dose (700 rad) whole body irradiation, transfer of primed spleen cells from hepatitis donor mice did not induce liver lesion in the lymphocyte-depleted mice. This low susceptibility of lymphocyte-depleted recipient mice to primed spleen cells of hepatitis mice was no longer demonstrated after reconstitution with normal spleen cells. In a cell-migration study using 51Cr-labelled spleen cells, it was shown that a considerable number of infiltrating cells in the liver of recipient mice were derived from recipient mice themselves. These results seem to indicate that cell-to-cell interaction between radiosensitive precursor cells of recipient mice and liver-antigen-primed T cells from hepatitis donor mice play an essential role in the induction of liver injury in the recipient mice.