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Biomedical subjects

C G Fathman

Publications and source records attributed to C G Fathman.

At least 55 records · Page 3Linked to original sources
PubMed1997

Local delivery of interleukin 4 by retrovirus-transduced T lymphocytes ameliorates experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory autoimmune disease of the central nervous system which serves as a model for the human disease multiple sclerosis. We demonstrate here that encephalitogenic T cells, transduced with a retroviral gene, construct to express interleukin 4, and can delay the onset and reduce the severity of EAE when adoptively transferred to myelin basic protein-immunized mice. Thus, T lymphocytes transduced with retroviral vectors can deliver "regulatory cytokines" in a site-specific manner and may represent a viable therapeutic strategy for the treatment of autoimmune disease.

Animals↗
PubMed1997

Rat pancreatic islet and skin xenograft survival in CD4 and CD8 knockout mice.

The relative contributions of the CD4+ and CD8+ T cell subpopulations in xenotransplant rejection were studied using CD4 and CD8 knockout (KO) mice. Wistar Furth (WF, RT1a) rat pancreatic islet or skin xenografts were transplanted into either CD4 or CD8 KO recipients and compared to wild-type controls. Long-term survival of WF islet xenografts was observed in the CD4 KO mice (MST, >66+/-8 days) whereas CD8 KO mice rejected their islet xenografts within 8 days, similar to controls (MST, 7+/-0.2 days). In contrast, WF skin xenografts were rejected in both CD4 and CD8 KO recipients within 8 days. CD4 KO recipients which maintained xenoislets >90 days posttransplant rejected WF skin grafts within 9 days, without rejecting their original islet xenografts. These results suggest that CD4+ cells are essential for mediating islet xenograft rejection. These data also suggest that the absence of either CD4+ or CD8+ T cells is not sufficient to prevent rejection of skin xenografts.

Animals↗
PubMed1997

CD45RBhigh CD4+ T cells from IFN-gamma knockout mice do not induce wasting disease.

Transfer of CD45RBhigh CD4+ T cells from normal mice to congenic SCID mice induces wasting disease, a murine model of inflammatory bowel disease. In this model, colonic inflammation is considered to be caused by a disregulated Th1 response, and Th1 cytokines, especially IFN-gamma, have been suggested to play an important role in the pathogenesis of wasting disease. In order to elucidate the potential role of IFN-gamma in the pathogenesis of wasting disease, we transferred CD45RBhigh CD4+ T cells from IFN-gamma knockout (GKO) mice to congenic SCID mice. The recipient mice were absolutely free of symptoms and clinical signs of disease and showed body-weight gain similar to that seen in normal mice. These data demonstrate the essential and non-redundant role of IFN-gamma in the pathogenesis of wasting disease.

Animals↗
PubMed1996

Induction of tolerance to small bowel allografts in high-responder rats by combining anti-CD4 with CTLA4Ig.

This study was designed to investigate the effectiveness of combined perioperative anti-CD4 and human (h)CTLA4Ig therapy in preventing allorejection of small bowel transplantation in high-responder Lewis rat recipients of ACI grafts. Anti-CD4 (5 mg/kg x 4 days) or hCTLA4Ig (0.5 mg/rat x 2 days) therapy alone delayed, but did not prevent, allograft rejection after small bowel transplantation of ACI into Lewis rats. All grafts were rejected in 18 and 10 days, respectively. However, a regimen of anti-CD4 (5 mg/kg x 4 days) combined with hCTLA4Ig (0.5 mg/rat x 2 days) allowed indefinite survival of ACI small bowel allografts. Second donor-matched heart grafts were permanently accepted, whereas third-party (Sprague-Dawley) heart allografts were rejected by the tolerant recipients. These data suggest that these two reagents produced a synergistic effect in preventing allorejection of small bowel transplantation.

Abatacept↗
PubMed1996

CD4+ but not CD8+ cells are essential for allorejection.

The generation of knockout mice with targeted gene disruption has provided a valuable tool for studying the immune response. Here we describe the use of CD4 and CD8 knockout mice to examine the role of CD4+ and CD8+ cells in initiating allotransplantation rejection. Pretreatment with a brief course of depletive anti-CD4 monoclonal antibody therapy allowed permanent survival of heart, but not skin, allografts transplanted across a major histocompatibility barrier. However, skin as well as heart grafts were permanently accepted in the CD4 knockout mice. Transfer of CD4+ cells into CD4 knockout recipient mice 1 d before skin engraftment reconstituted rejection, demonstrating that CD4+ cells are necessary for initiating rejection of allogeneic transplants. Major histocompatibility complex disparate heart and skin allografts transplanted into CD8 knockout recipients were rejected within 10 d. This study demonstrates that CD4+ but not CD8+ T cells are absolutely required to initiate allograft rejection.

Adoptive Transfer↗
PubMed1996

Quantitative analysis of T cell activation: role of TCR/ligand density and TCR affinity.

(B6 X A)F1 mice were immunized with sperm whale myoglobin, and T cell clones and hybridomas were generated. Hybridoma 74a.e9 was specific for the sperm whale myoglobin 67-79 peptide and could be partially activated by a peptide analogue, equine myoglobin with a natural 74G substitution. Using this hybridoma in T cell activation assays, we studied the effects of varying the avidity of the TCR for its ligand, the concentration of MHC:peptide complex on the APC, and the density of TCR on the surface. Varying ligand concentration on the surface of the APC, the TCR avidity, or the density of TCR on the T cell were equally important parameters in driving T cell activation. The mouse myoglobin (74T) analogue, however, acted as an antagonist to the T cell response. Its effectiveness was also partially determined by its ability to bind to MHC. By independently altering each of these variables and following T cell activation, we describe the interrelationships among these three components (MHC:peptide:TCR) that control the activation of the T cell.

Amino Acids↗
PubMed1996

Breaking self-tolerance in nonobese diabetic mice.

Unresponsiveness to self is maintained through two mechanisms of immune regulation: thymic-negative selection and peripheral tolerance. Although thymic-negative selection is a major mechanism to eliminate self-reactive T cells, normal mice have readily detectable populations of T cells reactive to self-proteins but do not exhibit autoimmune responses. It has been postulated that autoimmune disease results from breakdown or loss of peripheral tolerance. We present data that demonstrate that peripheral tolerance or unresponsiveness to self can be broken in nonobese diabetic (NOD) mice. Immunization of NOD mice (but not of conventional mice) with self-peptides caused an immune response to self-peptide with resultant autoproliferation of peripheral lymphocytes. Autoproliferation of self-reactive T cells in NOD mice resulted from the recognition and proliferation of the activated T cells to endogenously processed and presented self-antigens. This loss of self-tolerance demonstrated in vitro may well be the basis of NOD autoimmune disease in vivo.

Amino Acid Sequence↗
PubMed1996

Treatment of experimental encephalomyelitis with a peptide analogue of myelin basic protein.

Following induction of experimental encephalomyelitis with a T-cell clone, L10C1, that is specific for the myelin basic protein epitope p87-99, the inflammatory infiltrate in the central nervous system contains a diverse collection of T cells with heterogeneous receptors. We show here that when clone L10C1 is tolerized in vivo with an analogue of p87-99, established paralysis is reversed, inflammatory infiltrates regress, and the heterogeneous T-cell infiltrate disappears from the brain, with only the T-cell clones that incited disease remaining in the original lesions. We found that antibody raised against interleukin-4 reversed the tolerance induced by the altered peptide ligand. Treatment with this altered peptide ligand selectively silences pathogenic T cells and actively signals for the efflux of other T cells recruited to the site of disease as a result of the production of interleukin-4 and the reduction of tumour-necrosis factor-alpha in the lesion.

Amino Acid Sequence↗
PubMed1996

Mice with a disrupted IFN-gamma gene are susceptible to the induction of experimental autoimmune encephalomyelitis (EAE).

Experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, is an autoimmune disorder seen in mice and rats following immunization with myelin basic protein (MBP) or MBP-derived peptides. IFN-gamma, a cytokine produced by a variety of cells, is involved in many inflammatory and immune regulatory events. Contradictory results concerning exacerbations and the disease course were seen comparing injections of IFN-gamma in humans suffering from multiple sclerosis to studies using anti-IFN-gamma Abs in mice with EAE. To study the role of IFN-gamma and IFN-gamma-producing cells in EAE, we crossed IFN-gamma knockout mice (H-2b) (unable to produce IFN-gamma due to the disruption of the IFN-gamma gene) with an EAE-susceptible mouse strain, B10.PL (H-2u). EAE was seen in IFN-gamma knockout mice, heterozygotic (IFN-gamma +/-) mice, as well as wild-type littermates following immunization with MBP. Histologic analyses of the central nervous system of IFN-gamma knockout mice with EAE revealed massive infiltrates composed of lymphocytes, macrophages, and granulocytes. We conclude that the presence of IFN-gamma is not crucial to the induction or the clinical course of EAE.

Animals↗
PubMed1996

Immune regulation in type 1 diabetes.

The non-obese diabetic (NOD) mouse is an animal model of insulin-dependent diabetes mellitus (IDDM) that shows many of the characteristics of human IDDM. In the NOD model, there exists a discrepancy between the onset of insulitis and diabetes suggesting the potential existence of some form of immune regulation that delays beta cell destruction. Our transfer system using NOD-scid/scid (NOD-scid) mice as recipients of donor NOD cells suggested that immune regulatory cells exist in the periphery of NOD mice, not in the islets. These regulatory cells are considered to be memory CD4+ cells which show a Th2 (or Th zero) type cytokine profile following activation in vitro. The function of the memory CD4+ cells seems to change from protective to pathogenic as the disease progresses. Moreover, cytokine profiles of this CD4+ CD45RBlow (memory) population shifted from a Th2 (or Th zero) to a Th1 type response coincident with the onset of hyperglycaemia. These data suggest that the progression of NOD disease from insulitis to frank hyperglycaemia is under the control of CD4+ CD45RBlow immune 'regulatory' cells.

Animals↗
PubMed1996

Monoclonal T cells identified in early NOD islet infiltrates.

To examine the hypothesis that a single initiating antigen was recognized by a monoclonal T cell population leading to subsequent inflammatory insulitis in non-obese (NOD) mouse islets, we examined the T cell receptor TCR V beta repertoire of islet-infiltrating T cells in very young (2-week-old) NOD mice. In independent experiments, we repeatedly identified one monoclonal TCR V-beta 8.2 gene product expressed by T lymphocytes infiltrating the islets of NOD mice at 2 weeks of age. The resultant inflammatory response quickly obscures the monoclonal nature of the initiating event. These data suggest that autoimmune diabetes in NOD mice may be initiated by recognition of a single autoantigen.

Age Factors↗
PubMed1996

Pathogenic and protective roles of CD45RB(low) CD4+ cells correlate with cytokine profiles in the spontaneously autoimmune diabetic mouse.

The adoptive transfer of splenocytes from diabetic NOD mice to NOD-scid/scid (NOD-scid) recipients results in diabetes. This model was used to test the effect of cotransfer of splenocyte subsets from young nondiabetic NOD mice. As shown previously in other NOD models, the CD4+ subset from young nondiabetic mice significantly delayed the onset of diabetes in splenocyte cotransfers (P < 0.001). The data presented here showed that the development of diabetes in NOD-scid recipients correlated with a rapid increase in peripheral CD45RB(low) CD4+ cells. However, the CD45RB(low) subset of CD4+ cells from young nondiabetic mice protected from diabetes transfer in this model. We therefore examined whether CD45RB(low) CD4+ cells from diabetic mice were pathogenic rather than protective. CD45RB(low) CD4+ splenocytes from diabetic NOD mice were transferred along with CD8+ splenocytes from diabetic mice into NOD-scid recipients, and all of the recipients became diabetic within 5 weeks posttransfer. In contrast, no recipients (0 of 10) of CD45RB(high) CD4+ cells along with CD8+ splenocytes from diabetic mice became diabetic within 5 weeks posttransfer (P < 0.001). A correlate for the difference between CD45RB(low) CD4+ cells from diabetic NOD mice and CD45RB(low) CD4+ cells from nondiabetic mice, which showed protective effect in splenocyte cotransfers, was found in cytokine production after stimulation with anti-CD3 antibodies in vitro. CD45RB(low) CD4+ cells from diabetic mice showed a significantly higher ratio (approximately fivefold) of gamma-interferon (IFN-gamma) to interleukin (IL)-4 when compared with CD45RB(low) CD4+ cells from nondiabetic mice (P < 0.001). In conclusion, the function of the CD45RB(low) population of CD4+ cells changes from a protective to a pathogenic one during the development of disease in the NOD mouse. This change in function correlates with cytokine production in vitro; increased IFN-gamma-to-IL-4 ratio is associated with pathogenic potential and occurs coincident with (or after) the onset of diabetes.

Animals↗
PubMed1996

Beta-cell destruction may be a late consequence of the autoimmune process in nonobese diabetic mice.

The NOD mouse is an animal model of IDDM that shows many of the characteristics of human IDDM. It has been proposed that beta-cell destruction in IDDM progresses over time in a linear manner. Recently, we and others have demonstrated that T helper type 1 (Th1) cells have pathogenic roles in the NOD model and proposed that cytokine balances change as the disease progresses. However, it has not been demonstrated how or when the cytokine balances change or how the beta-cell destruction progresses. We have recently demonstrated that the cytokine profiles of CD45RB(low) CD4+ cells correlate either with their pathogenic or with their protective roles in the NOD mouse. To further analyze this apparent correlation between the shift in cytokine level and IDDM, we examined the anti-CD3-induced cytokine profiles of this subset from NOD mice of various ages compared with that from age-matched I-Ak transgenic NOD and BALB/c mice as controls. A significantly higher ratio of anti-CD3-induced interferon-gamma/interleukin-4 was found in diabetic NOD mice (P < 0.0001) but not in age-matched nondiabetic NOD mice. This cytokine ratio did not change significantly until the onset of diabetes in NOD mice. Based upon these results, we propose that IDDM in the NOD mouse progresses as a predominant inflammatory beta-cell dysfunction without actual beta-cell destruction until late in the disease process. This supports the possibility that late-stage immunotherapy may preserve islet beta-cell mass.

Animals↗
PubMed1995

Ternary complex therapy for autoimmune disease.

Induction of an immune response is remarkably simple, involving the interaction of three components: processed antigen, an MHC class II molecule, and a CD4 T-cell receptor. Each part of this ternary complex represents a novel target for interventions that may block subsequent effector phenomena of autoimmune disease. Such specific treatments will be less toxic than those currently available.

Antigen-Antibody Complex↗
PubMed1995

Induction of tolerance to heart allografts in high responder rats by combining anti-CD4 with CTLA4Ig.

It has been difficult to induce donor-specific transplantation tolerance in high responder Lewis rats. Results presented below demonstrate that amounts of pretransplant anti-CD4 sufficient to allow allograft tolerance in low responder strains (5 mg/kg x 4 days) did not prevent the acute rejection of ACI heart allografts in high responder Lewis recipients. Higher doses of pretransplant anti-CD4 (10 mg/kg, 15 mg/kg, and 20 mg/kg) given alone could delay but not prevent allograft rejection. Pretransplant anti-CD4 combined with anti-CD8, thymectomy, and total lymphoid irradiation all failed to produce tolerance to ACI heart allografts. However, a regimen of anti-CD4 combined with CTLA4Ig allowed indefinite survival of ACI heart allografts (mean survival time, > 100 day). Second-donor matched heart grafts were permanently accepted, and third-party heart grafts were permanently accepted, and third-party heart allografts were rejected by the tolerant recipients. These results suggest a new combination therapeutic strategy for clinical transplantation.

Abatacept↗
PubMed1995

CD4-positive suppressor cells block allotransplant rejection.

Mechanisms of maintenance of transplantation tolerance induced in adult rats by depletive regimens of anti-CD4 before transplantation of vascularized heart allografts were studied. Despite the fact that there has been little evidence that tolerant lymphocytes could prevent allograft rejection after adoptive transfer, we demonstrated a suppressive role for lymphocytes from tolerant animals in vivo. These experiments analyzed the ability of lymphocytes from tolerant rats to protect passenger leukocyte-depleted Lewis heart grafts that had been "parked" in ACI rats (treated with pretransplant anti-CD4 and maintained for > 100 days) compared with their ability to protect transplantation of fresh Lewis heart grafts in naive ACI rats. Although parked Lewis heart grafts were rejected in unmanipulated ACI recipients, parked hearts (but not naive Lewis heart allografts), were permanently accepted by naive ACI rats when syngeneic tolerant spleen cells were adoptively transferred at the time of transplantation. Further, we demonstrated that the suppressor cells in the tolerant spleen cells were CD4+. These results suggest that CD4+ spleen cells from tolerant rats inhibit allograft recognition and may maintain allograft tolerance by blocking the indirect pathway of allorecognition.

Animals↗
PubMed1995

Tissue-specific effects of anti-CD4 therapy in induction of allograft unresponsiveness in high and low responder rats.

In these experiments, we studied the role of anti-CD4 (Ox38) monoclonal antibody in the prevention of heart and/or kidney allograft rejection in low (ACI) and high (Lewis) responder rats. In low responder ACI rats, donor-specific tolerance for heart and kidney allografts (individually or in combination) was achieved by pretransplant anti-CD4 therapy. In high responder Lewis rats, anti-CD4 therapy alone (or combined with anti-CD8 (Ox8), thymectomy or total lymphoid irradiation) did not prevent first-set rejection of heart allografts. This difference was correlated with a more profound and longer lasting CD4+ cell depletion in the low responder strain. Anti-CD4 treatment, however, produced tolerance of kidney transplants in high responder rats. Additionally, anti-CD4 treatment induced tolerance to heart (as well as kidney) allografts in Lewis recipients of combined kidney and heart allografts from ACI. The effects of anti-CD4 treatment thus depend upon the recipient responder status as well as the organs transplanted and the order of transplantation.

Animals↗