1
|
Fitch Z, Schmitz R, Kwun J, Hering B, Madsen J, Knechtle SJ. Transplant research in nonhuman primates to evaluate clinically relevant immune strategies in organ transplantation. Transplant Rev (Orlando) 2019; 33:115-129. [PMID: 31027947 PMCID: PMC6599548 DOI: 10.1016/j.trre.2019.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/08/2019] [Accepted: 03/26/2019] [Indexed: 12/27/2022]
Abstract
Research in transplant immunology using non-human primate (NHP) species to evaluate immunologic strategies to prevent rejection and prolong allograft survival has yielded results that have translated successfully into human organ transplant patient management. Other therapies have not proceeded to human translation due to failure in NHP testing, arguably sparing humans the futility and risk of such testing. The NHP transplant models are ethically necessary for drug development in this field and provide the closest analogue to human transplant patients available. The refinement of this resource with respect to colony MHC typing, reagent and assay development, and availability to the research community has greatly enhanced knowledge about transplant immunology and drug development.
Collapse
Affiliation(s)
- Zachary Fitch
- Department of Surgery, Duke Transplant Center, Durham, NC 27710, USA; Center for Transplantation Sciences, Division of Cardiac Surgery, Department of Surgery, Massachusetts General Hospital, White 510c, 55 Fruit Street, Boston, MA, USA
| | - Robin Schmitz
- Department of Surgery, Duke Transplant Center, Durham, NC 27710, USA
| | - Jean Kwun
- Department of Surgery, Duke Transplant Center, Durham, NC 27710, USA
| | - Bernhard Hering
- Schulze Diabetes Institute, Department of Surgery, University of Minnesota, Minneapolis, MN, USA
| | - Joren Madsen
- Department of Surgery, Duke Transplant Center, Durham, NC 27710, USA
| | - Stuart J Knechtle
- Department of Surgery, Duke Transplant Center, Durham, NC 27710, USA.
| |
Collapse
|
2
|
Recombinant anti-monkey CD3 immunotoxin depletes peripheral lymph node T lymphocytes more effectively than rabbit anti-thymocyte globulin in naïve baboons. Transpl Immunol 2013; 29:60-3. [PMID: 24157659 DOI: 10.1016/j.trim.2013.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/10/2013] [Accepted: 10/14/2013] [Indexed: 12/19/2022]
Abstract
T cell depletion is an important procedure for both experimental and therapeutic immune modulation. Rabbit anti-thymocyte globulin (ATG), which is a commonly used T cell depletion antibody in clinical organ and cell transplantation protocols, is effective in temporarily depleting peripheral blood T lymphocytes but only moderately effective in depleting peripheral lymph node T cells which comprise the majority of T lymphocytes. A recombinant anti-CD3 immunotoxin, A-dmDT390-scfbDb (C207), has been developed and shown in an initial study to retain the lymph node depleting properties of conjugated CD3 immunotoxin. This agent could potentially be used synergistically with or as a replacement for rabbit ATG in preclinical primate models of transplantation. We directly compared the peripheral blood and lymph node depleting abilities of this recombinant anti-CD3 immunotoxin and rabbit ATG in naïve animals at clinically tolerated doses. Baboons were treated with a full course of either rabbit ATG (n=2) or CD3 immunotoxin (n=3). Peripheral blood and lymph node T lymphocytes were measured before and following treatment. Peripheral blood CD3+ cells fell below 100cells/μL in every animal. In the two animals receiving ATG, CD3+ cells represented 53% and 68% of lymph node cells two days following a full course of rabbit ATG. In contrast, CD3+ cells represented 3%, 5%, and 38% in lymph nodes following a full course of CD3-IT. Thus, recombinant anti-monkey CD3 immunotoxin showed improved peripheral lymph node T lymphocyte depletion to rabbit ATG and spared other immune cells.
Collapse
|
3
|
|
4
|
Hale DA, Dhanireddy K, Bruno D, Kirk AD. Induction of transplantation tolerance in non-human primate preclinical models. Philos Trans R Soc Lond B Biol Sci 2006; 360:1723-37. [PMID: 16147537 PMCID: PMC1569541 DOI: 10.1098/rstb.2005.1703] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Short-term outcomes following organ transplantation have improved considerably since the availability of cyclosporine ushered in the modern era of immunosuppression. In spite of this, many of the current limitations to progress in the field are directly related to the existing practice of relatively non-specific immunosuppression. These include increased risks of opportunistic infection and cancer, and toxicity associated with long-term immunosuppressive drug exposure. In addition, long-term graft loss continues to result in part from a failure to adequately control the anti-donor immune response. The development of a safe and reliable means of inducing tolerance would ameliorate these issues and improve the lives of transplant recipients, yet given the improving clinical standard of care, the translation of new therapies has become appropriately more cautious and dependent on increasingly predictive preclinical models. While convenient and easy to use, rodent tolerance models have not to date been reliably capable of predicting a therapy's potential efficacy in humans. Non-human primates possess an immune system that more closely approximates that found in humans, and have served as a more rigorous preclinical testing ground for novel therapies. Prior to clinical adaptation therefore, tolerance regimens should be vetted in non-human primates to ensure that there is sufficient potential for efficacy to justify the risk of its application.
Collapse
Affiliation(s)
- Douglas A Hale
- Digestive and Kidney Diseases, National Institute of Diabetes, NIH, Transplantation Branch, Bethesda, MD 20892, USA.
| | | | | | | |
Collapse
|
5
|
Abstract
Recent advances in the field of reconstructive surgery and immunology resulted in increased interest in composite tissue allograft (CTA) transplantation. Up to date, more than 50 CTA transplants have been reported in humans. A significant number of experimental studies on CTA transplants under different protocols of tolerance-inducting strategies have been reported in small-animal models. There is however, a limited number of CTA transplants performed in nonhuman primates. To reach the ultimate clinical success in CTA transplantation, more experimental studies on tolerance induction in nonhuman primates are needed to apply these immunomodulatory protocols to CTA transplants in humans. In this review, strategies for tolerance induction in the nonhuman primate model in solid organ and CTA transplants are presented in 3 major categories: chimerism induction, T-cell depletion, and costimulatory receptor blockade.
Collapse
Affiliation(s)
- Maria Siemionow
- Department of Plastic Surgery, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
| | | |
Collapse
|
6
|
Wang Z, Mathias A, Stavrou S, Neville DM. A new yeast display vector permitting free scFv amino termini can augment ligand binding affinities. Protein Eng Des Sel 2005; 18:337-43. [PMID: 15976011 DOI: 10.1093/protein/gzi036] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Yeast surface display and sorting by flow cytometry are now widely used to direct the evolution of protein binding such as single-chain antibodies or scFvs. The available commercial yeast display vector pYD1 (Invitrogen) displays the protein of interest flanked on the N-terminus by Aga2, the disulfide of which binds the myristylated surface membrane protein Aga1. We have noted that two anti-CD3epsilon scFvs expressed as fusion proteins suffer a 30- to 100-fold loss of affinity when placed NH(2) terminal to either truncated toxins or human serum albumin. In the course of affinity maturing one of these scFv (FN18) using pYD1 we noted that the affinity towards the ectodomain of monkey CD3epsilongamma was too low to measure. Consequently we rebuilt pYD1 tethering the scFv off the NH(2) terminus of Aga2. This display vector, pYD5, now gave a positive signal displaying FN18 scFv with its ligand, monkey CD3epsilongamma. The apparent equilibrium association constant of the higher affinity scFv directed at human CD3epsilongamma increased approximately 3-fold when displayed on pYD5 compared with pYD1. These data show that for certain yeast-displayed scFvs a carboxy-tethered scFv can result in increased ligand-scFv equilibrium association constants and thereby extend the low range of affinity maturation measurements.
Collapse
Affiliation(s)
- Z Wang
- Section on Biophysical Chemistry, Laboratory of Molecular Biology, National Institute of Mental Health, Building 10, 36 Convent Drive, Bethesda, MD 28092-4034, USA
| | | | | | | |
Collapse
|
7
|
Abstract
Introduction of modern immunosuppressive agents has led to great success of allotransplantation in humans, and survival rates for all solid organs have been dramatically improved. However, a constant proportion of organs is lost every year due to chronic allograft rejection and immunosuppressive drug toxicity. This has led to a situation where, despite the of donor organ shortage, about one third of the patients on the kidney transplant waiting list are listed for a retransplant. The induction of donor-specific tolerance has the potential of at least partially resolving this problem, since it might prevent chronic rejection and drug toxicity at the same time. For a variety of protocols, successful tolerance induction has been demonstrated in rodent models. However, translation of such protocols to large animal models and on clinical trials has turned out to be very difficult. This review briefly describes mechanisms and barriers to transplantation tolerance, and then focuses on pre-clinical and clinical studies in non-human primates and humans. We have divided the strategies into two groups, based on the principle mechanisms of tolerance induction: the first group are protocols not using hematopoietic stem cell transplantation (HCT) as part of there regimen. They rely mainly on intensive T cell depletion (either by total body irradiation, total lymphoid irradiation or treatment with T cell-depleting agents such as anti-thymocyte globulin, anti-CD52 antibody or CD3 immunotoxin), which have been combined with costimulatory blockade, signaling blockade or donor antigen infusion. The second group are HCT-based protocols combining HCT with T cell-depleting agents and cytoreductive treatment. So far, only two protocols (one with total lymphoid irradiation and anti-thymocyte globulin, but no HCT; one with HCT, cyclophosphamide, anti-thymocyte globulin and thymic irradiation) have been translated into successful human studies. We summarize and discuss the results of these trials and suggest goals for further studies for the development tolerance protocols applicable for a broad population of allograft recipients.
Collapse
Affiliation(s)
- Thomas Fehr
- Transplantation Biology Research Center, Bone Marrow Transplantation Section, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA.
| | | |
Collapse
|
8
|
Abstract
Many methods for reducing the immunosuppressive requirements of allotransplantation have been proposed based on a growing understanding of physiological and allospecific immunity. As these regimens are developed for clinical application, they require validation in models that are reasonably predictive of their performance in humans. This article provides an overview of the large animal models commonly used to test immunomodulatory organ transplant protocols. The rationale for the use of large animals and the effects of common immunosuppressants in the dog, pig, and non-human primate are reviewed. Promising methods for the induction of allospecific tolerance are surveyed with references to early human trials where appropriate.
Collapse
Affiliation(s)
- Allan D Kirk
- Transplantation Section, Transplantation and Autoimmunity Branch, National Institute of Diabetes, Digestive and Kidney Diseases/NIH/DHHS, Building 10, Room 11S/219, Bethesda, MD 20892, USA.
| |
Collapse
|
9
|
Kanmaz T, Fechner JJH, Torrealba J, Kim HT, Dong Y, Oberley TD, Schultz JM, Bloom DD, Katayama M, Dar W, Markovits J, Schuler W, Hu H, Hamawy MM, Knechtle SJ. Monotherapy with the novel human anti-CD154 monoclonal antibody ABI793 in rhesus monkey renal transplantation model. Transplantation 2004; 77:914-20. [PMID: 15077037 DOI: 10.1097/01.tp.0000116392.72152.75] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND This study assesses the safety and efficacy of the novel human anti-human CD154 monoclonal antibody ABI793 in rhesus monkeys. METHODS Outbred rhesus monkeys were used for renal transplantation from major histocompatibility complex-mismatched donors. Seven recipients were treated with ABI793, and six untreated recipients were used as controls. Graft function was monitored by urine output, serum creatinine, and renal biopsy. Phenotypic analysis of peripheral blood lymphocytes and mixed lymphocyte reaction were performed before transplantation and periodically after transplantation. Anti-donor major histocompatibility complex class I antibody levels were measured at the time of sacrifice. RESULTS Monkeys in the treated group demonstrated prolonged graft survival compared with controls. One monkey was sacrificed because of a urine leak on postoperative day 13. Three monkeys were sacrificed because of acute rejection (days 44, 149, and 158). Two monkeys were sacrificed because of chronic active rejection (days 154 and 221). One monkey was sacrificed on day 139 without rejection to observe the effects of ABI793 in the absence of rejection. There were no obvious clinical side effects of ABI793, but microscopic thromboembolic changes were observed in two monkeys. Lymphocyte subsets remained unaltered in all monkeys. Mixed lymphocyte reaction showed nonspecific suppression 6 weeks after transplantation. The monkeys with chronic active rejection showed relatively strong alloantibody responses. CONCLUSIONS ABI793 induces prolonged renal allograft survival in rhesus monkeys. Nevertheless, thromboembolic complications may occur and chronic allograft nephropathy may develop after anti-CD154 treatment is discontinued.
Collapse
Affiliation(s)
- Turan Kanmaz
- Department of Surgery, University of Wisconsin, Madison, Wisconsin 53792, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Abstract
It is clear that both humans and nonhuman primates can do without immunosuppression for long periods of time before rejecting their allogeneic organ transplants. Immune cell depletion, particularly lymphocyte depletion, is an effective clinical strategy for achieving a tolerant state. Based on nonhuman primate and human studies, evidence suggests that metastable tolerance develops over time in a donor-specific manner and is mediated at least in part by donor antigen-specific regulatory T cells. Suppression of effector T cells by CD8+ and CD4+ T-regulatory cells is mediated by transforming growth factor (TGF)-beta or interleukin 10, and the presence of CD4+ TGF beta(latent) T-cell infiltrates may be a useful diagnostic marker for metastable tolerance. Loss of these cells has been shown to correlate with loss of tolerance. Future efforts to withdraw immunosuppressive drugs and establish a tolerant state will depend importantly on development of such diagnostic immunologic monitoring tools. Some of the reasons that tolerance remains such a challenging goal in clinical transplantation are discussed herein.
Collapse
Affiliation(s)
- Stuart J Knechtle
- Division of Transplantation, Department of Surgery, University of Wisconsin Medical School, Madison, WI 53792-7375, USA.
| | | |
Collapse
|
11
|
Wu A, Yamada K, Neville DM, Awwad M, Wain JC, Shimizu A, Gojo S, Kitamura H, Colvin RB, Cooper DKC, Sykes M, Sachs DH. Xenogeneic thymus transplantation in a pig-to-baboon model. Transplantation 2003; 75:282-91. [PMID: 12589146 DOI: 10.1097/01.tp.0000044137.97841.99] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND We have tested whether fetal porcine thymic tissue transplantation can lead to tolerance across a discordant (pig-to-baboon) xenogeneic barrier. METHODS Six baboons underwent a conditioning regimen with thymectomy, splenectomy, and anti-monkey CD3 antibody conjugated to a diphtheria toxin binding site mutant (FN18-CRM9). Porcine fetal or neonatal thymic tissue was transplanted into three baboons. Three control baboons received either no transplanted pig tissue (n=1) or adult pig lymph node (n=2). Cellular responses and skin xenografts were used to test for tolerance. RESULTS After T-cell depletion and thymic transplantation, recovery of thymus-dependent naïve-type CD4 cells (CD4/CD45RA ) and in vitro xenogeneic hyporesponsiveness were observed. No sensitization of alpha-galactosyl antibody responses was observed. The thymic grafts survived up to 48 days. Porcine skin xenografts were performed in two of these animals with survival of 22 and 24 days. Only two of these animals were completely T-cell depleted, and both failed to recover thymus-dependent T cells (CD4/CD45RA ). In one animal, general in vitro hyporesponsiveness was observed, with subsequent death from infection. The second animal demonstrated delayed recovery of T cells and prolonged general hyporesponsiveness in vitro. Neither animal demonstrated prolongation of porcine skin grafts compared with allografts (both rejected by day 13). CONCLUSIONS Porcine thymic tissue is able to induce xenogeneic hyporesponsiveness. More efficient thymic engraftment may allow this approach to induce xenograft tolerance.
Collapse
Affiliation(s)
- Anette Wu
- Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02129, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Abstract
T-cell depletion prior to or beginning at the time of transplantation has been shown to be a valuable adjunct to the induction of immunological unresponsiveness. Both total lymphoid irradiation and anti-lymphocyte globulin have been used for this purpose in experimental models of transplantation as well as in human organ transplant recipients. However, these methods of T-cell depletion are limited in their ability to deplete T cells selectively due to non-specific targeting and limited efficacy. A new anti-CD3 immunotoxin has been developed with a far more potent ability to deplete T cells selectively as measured by flow cytometry analysis of peripheral blood T lymphocytes as well as lymph node lymphocytes. This immunotoxin is well tolerated by rhesus monkeys when administered in vivo. When administered as a single immunosuppressive agent pretransplant, it substantially promotes allograft survival, inducing tolerance in at least one-third of recipients as measured by subsequent acceptance of donor skin grafts and rejection of third-party skin grafts. When administered on the day of transplant in combination with steroid pretreatment and a brief course of deoxyspergualin or mycophenolate mofetil (4 to 14 days), long-term unresponsiveness is also produced and in a more reliable manner than using immunotoxin alone. A new immunotoxin directed at the human CD3epsilon has been developed with excellent potency in T-cell killing and lacking the Fc portion of the CD3 antibody. This construct may be useful for T-cell depletion in humans and has a potential application in tolerance induction in human organ transplantation. Lessons learned from anti-CD3 immunotoxin in the non-human primate model to date include (i) profound (2-3 log) depletion of T-cells can be accomplished safely without inducing lymphoma or infection, (ii) such depletion is a useful adjunct for tolerance induction to allogeneic organ transplants, and (iii) tolerance to both allogeneic renal transplants and xenogeneic islet transplants has been accomplished using such strategies to date in non-human primates and in pigs. Immunotoxin may be useful for the induction of chimerism using strategies that include donor bone marrow infusion. Successful strategies for tolerance induction have also been developed using immunotoxin without the adjunct of donor bone marrow or stem cell infusion. Clinical application of immunotoxin will use a newly engineered construct with the potential for causing cytokine release, less susceptibility to neutralization by anti-diphtheria antibody and not dependent on chemical conjugation of an antibody and toxin. The usefulness of immunotoxin is directly related to its tremendous potency for depleting T cells. Based on results in nonhuman primates, it is anticipated that it will become a useful agent in tolerance induction in humans.
Collapse
Affiliation(s)
- S J Knechtle
- Department of Surgery, Division of Organ Transplantation, 600 Highland Avenue, University of Wisconsin Medical School, Madison,WI 53792-7375, USA.
| |
Collapse
|
13
|
Fechner JH, Dong Y, Hong X, Brunner KG, Tsuchida M, Neville D, Scharff J, Lee F, Oberley TD, Peters D, Schultz JM, Manthei ER, Hamawy MM, Knechtle SJ. Graft survival in a rhesus renal transplant model after immunotoxin-mediated T-cell depletion is enhanced by mycophenolate and steroids. Transplantation 2001; 72:581-7. [PMID: 11544415 DOI: 10.1097/00007890-200108270-00005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Anti-CD3 immunotoxin (IT), a T-cell-depleting agent, prolongs survival of renal allografts in a rhesus monkey model without the need for long-term immunosuppression. In this study we sought to further prolong allograft survival by giving short-term conventional immunosuppression simultaneous with IT administration. METHODS MHC class II mismatched, juvenile rhesus monkeys were paired as donor and recipient for renal transplantation. Recipients received two to three daily doses of IT starting on the day of transplantation. Additional immunosuppression was given for no more than 60 days. Graft function was monitored by serum creatinine and renal biopsies. Flow cytometry was used to monitor T-cell recovery. RESULTS Graft survival time (GST) in animals receiving IT was prolonged compared with controls with 50% of IT-treated monkeys surviving >100 days. Animals treated with IT plus mycophenolate mofetil (MMF) and steroids had significantly enhanced GST (mean GST, 305 days) compared with those treated with IT alone (mean GST, 94 days). In contrast, addition of cyclosporine or 40-O-[2-Hydroxyethyl]rapamycin did not significantly increase graft survival time. A comparison among animals from all treatment groups with short (<100 days) and long (>100 days) GST demonstrated that those with the shorter GST had a higher blood T-cell count 2 weeks after transplantation. Full recovery of CD4+ T cells required longer than 6 months. CONCLUSIONS A combination with MMF and steroids given for 4 days after renal allograft transplantation significantly increases GST in IT-treated monkeys. We hypothesize that MMF and steroids suppress the initial T-cell activation mediated by IT.
Collapse
Affiliation(s)
- J H Fechner
- Department of Surgery, University of Wisconsin, Madison 53792, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Hamawy MM, Tsuchida M, Cho CS, Manthei ER, Fechner JH, Knechtle SJ. Immunotoxin FN18-CRM9 induces stronger T cell signaling than unconjugated monoclonal antibody FN18. Transplantation 2001; 72:496-503. [PMID: 11502982 DOI: 10.1097/00007890-200108150-00023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The T-cell receptor (TCR)/CD3 complex is the target of therapeutic strategies aimed at prolonging allograft survival. The immunotoxin FN18-CRM9, composed of the anti-CD3 monoclonal antibody FN18 and the mutated diphtheria toxin CRM9, is useful for prolonging allograft survival in preclinical models of transplantation. To explore the influence of conjugation of the mutated diphtheria toxin on functional activation of the TCR/CD3 complex, we compared the effects of FN18-CRM9 and unconjugated FN18 on protein tyrosine phosphorylation and ligand/receptor internalization in purified monkey peripheral blood T cells. METHODS Purified normal rhesus monkey T cells were incubated with unconjugated FN18 or conjugated FN18-CRM9 and examined for differences in antibody binding, tyrosine phosphorylation, and CD3 internalization. RESULTS Binding cross-inhibition studies demonstrated that both compounds were able to inhibit fluorescein isothiocyanate-FN18 binding to CD3 with similar efficacy and potency. However, FN18-CRM9 was more potent than FN18 in triggering the phosphorylation of several proteins on tyrosine residues and in inducing CD3 internalization. The tyrosine kinase inhibitor genistein blocked FN18-CRM9-induced protein tyrosine phosphorylation and CD3 internalization, suggesting that tyrosine phosphorylation is involved in the internalization of the immunotoxin. Interestingly, in FN18-CRM9- but not FN18-treated cells, there was a gradual decrease in cellular CD3 protein levels within 24 and 48 hr; such a decrease was not observed with the control protein Csk. CONCLUSIONS Our findings suggest that the conjugation of the mutated diphtheria toxin CRM9 to FN18 modulates the monoclonal antibody-mediated cross-linking of the TCR/CD3 complex, leading to a stronger protein tyrosine phosphorylation and CD3 internalization. This may in turn contribute to the greater efficacy of the immunotoxin in prolonging allograft survival.
Collapse
Affiliation(s)
- M M Hamawy
- Department of Surgery, Division of Transplantation, University of Wisconsin, Clinical Sciences Center H4/749, 600 Highland Avenue, Madison, WI 53792.
| | | | | | | | | | | |
Collapse
|
15
|
Ko S, Jager MD, Tsui TY, Deiwick A, Dinkel A, Rohde F, Dahlke MH, Lauth O, Wonigeit K, Schlitt HJ. LONG-TERM ALLOGRAFT ACCEPTANCE INDUCED BY SINGLE DOSE ANTI-LEUKOCYTE COMMON ANTIGEN (RT7) ANTIBODY IN THE RAT1. Transplantation 2001; 71:1124-31. [PMID: 11374414 DOI: 10.1097/00007890-200104270-00020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND In clinical organ transplantation monoclonal antibodies (mAb) to different surface molecules of immunocompetent cells become integral parts of the immunosuppressive therapy. In this study, a mAb against the rat leukocyte common antigen CD45 (RT7) was tested for its immunosuppressive potency after a single perioperative injection. METHODS Binding and depleting properties of the anti-RT7 mAb were investigated by flow cytometry. In the fully major histocompatibility complex-disparate heart and skin transplantation models (LEW [RT1l]--> LEW.1W [RT1u]), a single dose of anti-RT7 mAb (10 mg/kg) was administered intravenously (day -1). To characterize the long-term acceptance of heart allografts second set skin transplantation (day 100), mixed lymphocyte reaction studies (day 100) and reverse transcriptase-polymerase chain reaction analysis for intragraft cytokine expression (day 200) were performed. RESULTS The anti-RT7 mAb bound to nearly all hematopoietic lineage cells, but particularly T and NK cells, and profoundly depleted these cells in circulation and lymphoid tissues. Anti-RT7 mAb-treated rats showed long-term acceptance of heart allografts (>200 days; n=12), whereas untreated recipients rejected allografts by day 8 (n=6). In contrast to hearts, primary skin allograft survival was only moderately prolonged. Animals with stable heart allograft acceptance showed normal in vitro lymphocyte proliferation responses to donor and third party antigen. These recipients also acutely rejected second set donor-strain skin grafts without inducing rejection of persisting heart allografts. Reverse transcriptase-polymerase chain reaction analysis of intragraft cytokines showed up-regulation of Fas-ligand and IL-4 mRNA in long-surviving heart allografts. CONCLUSIONS The findings demonstrate that a single injection of an anti-RT7 mAb in the rat can induce stable long-term acceptance of heart allografts by transient but profound T-cell depletion. Local immunoregulatory mechanisms seem to play a role for maintenance of long-term graft acceptance.
Collapse
Affiliation(s)
- S Ko
- Klinik für Viszeral und Transplantationschirurgie, Medizinische Hochschule Hannover, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Orosz CG. Considerations regarding the contributions of B cells to chronic allograft rejection in experimental animal models. J Heart Lung Transplant 2000; 19:634-7. [PMID: 10930811 DOI: 10.1016/s1053-2498(00)00102-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- C G Orosz
- Ohio State University College of Medicine, Columbus, Ohio 43210-1250, USA
| |
Collapse
|
17
|
Thomas JM, Eckhoff DE, Contreras JL, Lobashevsky AL, Hubbard WJ, Moore JK, Cook WJ, Thomas FT, Neville DM. Durable donor-specific T and B cell tolerance in rhesus macaques induced with peritransplantation anti-CD3 immunotoxin and deoxyspergualin: absence of chronic allograft nephropathy. Transplantation 2000; 69:2497-503. [PMID: 10910269 DOI: 10.1097/00007890-200006270-00007] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Tolerance induction can prevent acute kidney allograft rejection without chronic immunosuppression. It is uncertain whether specific tolerance can prevent chronic allograft nephropathy (CAN), which involves both nonimmune and immune injury. This report provides evidence that immunologically tolerant macaques, induced with immunotoxin and deoxyspergualin, developed neither acute rejection nor CAN. Long survivors, bearing MHC-mismatched grafts without chronic immunosuppression for 0.8 to 3.4 years, exhibited general immune competence with donor-specific T and B cell tolerance and no functional or histological evidence of CAN. Stringent criteria for tolerance were satisfied by specific prolongation of donor skin grafts with rapid rejection of third-party skin, followed by indefinite acceptance of a second donor kidney graft and establishment of microchimerism. Primate tolerance with documented absence of CAN may give impetus to the clinical application of tolerance.
Collapse
Affiliation(s)
- J M Thomas
- Transplant Center, Department of Surgery and Pathology, University of Alabama at Birmingham, 35294, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
|
19
|
|
20
|
Poston RS, Robbins RC, Chan B, Simms P, Presta L, Jardieu P, Morris RE. Effects of humanized monoclonal antibody to rhesus CD11a in rhesus monkey cardiac allograft recipients. Transplantation 2000; 69:2005-13. [PMID: 10852588 DOI: 10.1097/00007890-200005270-00006] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Leukocyte function-associated antigen-1 (LFA-1, CD11a) monoclonal antibody (mAb) affects many leukocyte functions without cell depletion. We hypothesized that the use of a humanized, anti-rhesus modified LFA-1 mAb (H2C12) in rhesus monkeys would cause: (1) prolonged heart allograft survival, (2) inhibition of primary but not secondary antibody responses, and (3) minimal drug toxicity. METHODS AND RESULTS Control (n=5) and H2C12-treated (n=7) (8-20 mg/kg i.v. on day -1 followed by 10 mg/kg/day) adult male rhesus recipients were inoculated with GP120 protein antigen on day -28 and -1 and grafted with heterotopic abdominal hearts (day 0). Donor-recipient pairs were equally MLR mismatched (4329.8+/-1124.1 CPM controls vs. 7289.0+/-1926.5 treated, P=NS). Mean heart allograft survival as evaluated by daily abdominal palpation was significantly prolonged in high dose recipients (23.0+/-2.6, n=4) vesus controls (8.2+/-1.3, n=5, P<0.02, Mann-Whitney U test). H2C12 treatment did not produce signs of cytokine release or toxicity, was nondepleting, but down-modulated PBL CD11a expression to 43.4+/-3.6% (n=4) of control levels (n=5) at day 7 as demonstrated by flow cytometry. It had no effect on postoperative Con A or MLR and did not prevent mAb clearance due to the rhesus-antihuman antibody response. The addition of mycophenolate mofitil prevented rhesus-antihuman antibody response with therapeutic H2C12 levels seen for >35 days. CONCLUSIONS The use of this mAb to block CD11a had the benefit of being a well tolerated, highly targeted therapy. These are the first results showing that monotherapy with anti-leukocyte function-associated antigen-1 mAb prolonged survival of MLR mismatched allogenic cardiac grafts in primates.
Collapse
Affiliation(s)
- R S Poston
- Transplantation Immunology, Department of Cardiothoracic Surgery, Stanford University School of Medicine, CA 94305-5247, USA
| | | | | | | | | | | | | |
Collapse
|
21
|
de Haan A, van der Gun I, Hepkema BG, de Boer WJ, van der Bij W, de Leij LF, Prop J. Decreased donor-specific cytotoxic T cell precursor frequencies one year after clinical lung transplantation do not reflect transplantation tolerance: a comparison of lung transplant recipients with or without bronchiolitis obliterans syndrome. Transplantation 2000; 69:1434-9. [PMID: 10798767 DOI: 10.1097/00007890-200004150-00038] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Decreased in vitro T cell alloreactivity, demonstrated by decreased frequencies of peripheral blood donor-specific T cell precursors, may reflect a tolerant state after transplantation and lower the risk for development of chronic graft dysfunction. It is unknown whether a decrease in donor-specific T cell frequencies also occurs after clinical lung transplantation and if such a decrease lowers the risk for bronchiolitis obliterans syndrome (BOS), a hallmark of chronic graft dysfunction. Therefore, we compared changes in posttransplant donor-specific cytotoxic T lymphocyte (CTLp) and helper T lymphocyte precursor (HTLp) frequencies in lung allograft recipients with good graft function and in recipients with BOS. METHODS Donor and third party specific CTLp and HTLp frequencies were determined by limiting dilution assay in pre- and posttransplant (1 year) peripheral blood samples of lung allograft recipients with good graft function (n = 13) and BOS (n = 10). RESULTS In recipients with good graft function, mean donor-specific CTLp frequencies decreased after transplantation (183 vs. 16 precursors before and after transplantation, respectively). Additionally, HTLp frequencies decreased but this was not specific for donor alloantigens because third party-specific HTLp frequencies decreased also. Surprisingly, recipients with BOS also showed a decrease in mean donor-specific CTLp frequencies after transplantation (332 vs. 49 precursors before and after transplantation, respectively). Again, HTLp frequencies decreased nonspecifically. CONCLUSIONS We conclude that donor-specific CTLp frequencies decrease after lung transplantation, but that this does not result in transplantation tolerance protecting the lung against the development of chronic graft dysfunction.
Collapse
Affiliation(s)
- A de Haan
- Department of Cardiopulmonary Surgery, University Hospital Groningen, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
22
|
|
23
|
Urvater JA, Steffen SR, Rehrauer W, Watkins DI. An unusual insertion in intron 2 of apparently functional MHC class I alleles in rhesus macaques. TISSUE ANTIGENS 2000; 55:153-6. [PMID: 10746787 DOI: 10.1034/j.1399-0039.2000.550207.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Here we describe a nucleotide insertion in intron 2 of two rhesus major histocompatibility complex (MHC) class I alleles, Mamu-A*05 and Mamu-A*07. This resulted in an intron 2 that was nearly twice the length of any other intron 2 of primate MHC class I genes sequenced to date. This insertion was most similar (93% identity) to the beginning of intron 3 of HLA-A alleles. It was also similar to intron 3 of several human MHC class I pseudogenes and MHC class I pseudogenes from cotton top tamarin and cat. The finding of this insertion in two rhesus MHC class I genes is surprising given the uniformity in length and sequence of introns of functional HLA-A, -B and -C genes.
Collapse
Affiliation(s)
- J A Urvater
- Wisconsin Regional Primate Research Center, University of Wisconsin-Madison, 53715, USA
| | | | | | | |
Collapse
|
24
|
Urvater JA, Otting N, Loehrke JH, Rudersdorf R, Slukvin II, Piekarczyk MS, Golos TG, Hughes AL, Bontrop RE, Watkins DI. Mamu-I: a novel primate MHC class I B-related locus with unusually low variability. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:1386-98. [PMID: 10640754 DOI: 10.4049/jimmunol.164.3.1386] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The rhesus macaque is an important animal model for several human diseases and organ transplantation. Therefore, definition of the MHC of this species is crucial to the development of these models. Unfortunately, unlike humans, lymphocytes from a single rhesus macaque express up to 12 different MHC class I cDNAs. From which locus these various alleles are derived is unclear. In our attempts to define the MHC class I loci of the rhesus macaque, we have identified an unusual MHC class I locus, Mamu-I. We isolated 26 I locus alleles from three different macaque species but not from three other Cercopithecine genera, suggesting that the I locus is the result of a recent duplication of the B locus occurring after the divergence of macaques from the ancestor of the other extant Cercopithecine genera. Mamu-I mRNA transcripts were detected in all tissues examined and Mamu-I protein was produced in rhesus B lymphoblastoid cell lines. Furthermore, Mamu-I protein was detected by flow cytometry on the surface of human 721.221 cells transfected with Mamu-I. In contrast to the polymorphism present at this locus, there is unusually low sequence variability, with the mean number of nucleotide differences between alleles being only 3.6 nt. Therefore, Mamu-I is less variable than any other polymorphic MHC class I locus described to date. Additionally, no evidence for positive selection on the peptide binding region was observed. Together, these results suggest that Mamu-I is an MHC class I locus in primates that has features of both classical and nonclassical loci.
Collapse
Affiliation(s)
- J A Urvater
- Wisconsin Regional Primate Research Center, Department of Genetics, University of Wisconsin, Madison, WI 53715, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Tsuchida M, Manthei ER, Alam T, Knechtle SJ, Hamawy MM. Regulation of T cell receptor- and CD28-induced tyrosine phosphorylation of the focal adhesion tyrosine kinases Pyk2 and Fak by protein kinase C. A role for protein tyrosine phosphatases. J Biol Chem 2000; 275:1344-50. [PMID: 10625683 DOI: 10.1074/jbc.275.2.1344] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The T cell receptor (TCR)-CD3 complex and the costimulatory molecule CD28 are critical for T cell function. Both receptors utilize protein tyrosine kinases (PTKs) for the phosphorylation of various signaling molecules, a process that is critical for the function of both receptors. The PTKs of the focal adhesion family, Pyk2 and Fak, have been implicated in the signaling of TCR and CD28. We show here evidence for the regulation of TCR- and CD28-induced tyrosine phosphorylation of the focal adhesion PTKs by protein kinase C (PKC). Thus, treating Jurkat T cells with the PKC activator phorbol 12-myristate 13-acetate (PMA) rapidly and strongly reversed receptor-induced tyrosine phosphorylation of the focal adhesion PTKs. In contrast, PMA did not affect TCR-induced tyrosine phosphorylation of CD3zeta or the PTKs Fyn and Zap-70. However, PMA induced a strong and rapid dephosphorylation of the linker molecule for activation of T cells. PMA failed to induce the dephosphorylation of proteins in PKC-depleted cells or in cells pretreated with the PKC inhibitor Ro-31-8220, confirming the role of PKC in mediating the PMA effect on receptor-induced protein tyrosine phosphorylation. The involvement of protein tyrosine phosphatases (PTPases) in mediating the dephosphorylation of the focal adhesion PTKs was confirmed by the failure of PMA to dephosphorylate Pyk2 in cells pretreated with the PTPase inhibitor orthovanadate. These results implicate PKC in the regulation of receptor-induced tyrosine phosphorylation of the focal adhesion PTKs in T cells. The data also suggest a role for PTPases in the PKC action.
Collapse
Affiliation(s)
- M Tsuchida
- Department of Surgery, University of Wisconsin, Madison, Wisconsin 53792, USA
| | | | | | | | | |
Collapse
|
26
|
Thomas JM, Contreras JL, Jiang XL, Eckhoff DE, Wang PX, Hubbard WJ, Lobashevsky AL, Wang W, Asiedu C, Stavrou S, Cook WJ, Robbin ML, Thomas FT, Neville DM. Peritransplant tolerance induction in macaques: early events reflecting the unique synergy between immunotoxin and deoxyspergualin. Transplantation 1999; 68:1660-73. [PMID: 10609942 DOI: 10.1097/00007890-199912150-00009] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Day of transplant T cell depletion with anti-CD3 immunotoxin or F(Ab)2 immunotoxin induces stable tolerance to renal allografts in rhesus monkeys given 15-deoxyspergualin (DSG), a NF-kappaB inhibitor that suppresses proinflammatory cytokine (PC) production. Because PC and NF-kappaB are involved in dendritic cell (DC) maturation, we asked if impaired DC maturation and Th2-type cytokine deviation might be related to the synergistic effect of DSG in this novel model. METHODS Immunosuppression was initiated 4 hr before transplanting a major histocompatibility complex mismatched renal allograft. Some groups received a supplemental 5-day course of cyclosporine A or DSG or a 15-day course of DSG. Peripheral lymph nodes were sequentially examined for presence of mature DC. In vitro effects of DSG on PC-induced maturation of DC were also examined. RESULTS Allografts survived without rejection in 87% of recipients given immunotoxin or F(Ab)2 immunotoxin with DSG x 15 days, in 50% with DSG x 5 days, and 0% with cyclosporine A. The longest DSG survivors are >1000 days with normal graft function and tolerance validated, including acceptance of challenge second donor kidneys without treatment. DSG-treated recipients were unique in developing polarized Th2-type plasma cytokines. In DSG recipients, mature DC were significantly reduced in day +5 lymph node biopsies, with complete repopulation by 30 days. In vitro studies verified an inhibitory effect of DSG on DC maturation. CONCLUSIONS The study suggests DSG arrests DC maturation. The unusual synergy of immunotoxin and DSG apparently involves coincidental reduction in lymph node T cell mass and mature DC, a transient circumstance favoring development of stable tolerance.
Collapse
Affiliation(s)
- J M Thomas
- Department of Surgery, University of Alabama at Birmingham, 35294, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Abstract
Although studies of tolerance induction in large animals remain limited compared with murine studies, a number of encouraging observations have been recently reported - especially in nonhuman primate models. The development of antibodies or proteins binding to costimulatory molecules and of an immunotoxin that is active on T cells have been particularly important advances leading to expanded opportunities for extending strategies for tolerance induction to large animals.
Collapse
Affiliation(s)
- T Kawai
- Massachusetts General Hospital, Room White 510, Department of Surgery, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
| | | | | |
Collapse
|
28
|
Hamawy MM, Tsuchida M, Manthei ER, Dong Y, Fechner JE, Knechtle JS. Activation of T lymphocytes for adhesion and cytokine expression by toxin-conjugated anti-CD3 monoclonal antibodies. Transplantation 1999; 68:693-8. [PMID: 10507490 DOI: 10.1097/00007890-199909150-00016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Immunosuppressive drugs that target T cells are useful for prolonging allograft survival. The anti-CD3 immunotoxin FN18-CRM9 has been shown to effectively prolong renal allograft survival in a rhesus monkey model of transplantation. However, immunotoxin-treated monkeys showed increased levels of inflammatory cytokines and produced antibodies to donor proteins. To better understand the role of FN18-CRM9 in the production of cytokines and anti-donor antibodies in the monkey model, we examined whether this immunotoxin elicits functional responses in T cells. METHODS Purified normal rhesus monkey T cells (>98% purity) were incubated with immunotoxin FN18-CRM9 or the unconjugated anti-CD3 monoclonal antibodies and then examined for changes in protein tyrosine phosphorylation, adhesion to fibronectin, gene expression, and proliferation in the presence or absence of anti-CD28 monoclonal antibodies (mAb) and interleukin-2. RESULTS Immunotoxin treatment of T cells in vitro increased protein tyrosine phosphorylation, cell adhesion to the extracellular matrix, and expression of the inflammatory cytokines interferon-gamma and tumor necrosis factor-alpha. These immunotoxin effects were similar in magnitude to those induced by the unconjugated mAb. In contrast, immunotoxin-induced T cell proliferation was markedly less than that induced by the unconjugated mAb. Interestingly, the mitogenic molecules IL-2 and anti-CD28 mAb did not prevent immunotoxin-induced inhibition of cell proliferation. CONCLUSIONS The activation of T cells for protein phosphorylation, adhesion, and cytokine expression strongly suggests that the actions of FN18-CRM9 in vivo are not limited to the inhibition of protein synthesis.
Collapse
Affiliation(s)
- M M Hamawy
- Department of Surgery, University of Wisconsin, Madison 53792, USA
| | | | | | | | | | | |
Collapse
|
29
|
Knechtle SJ, Kirk AD, Fechner JH, Hong X, Dong Y, Hamawy MM, Harlan DM. Inducing unresponsiveness by the use of anti-CD3 immunotoxin, CTLA4-Ig, and anti-CD40 ligand. Transplant Proc 1999; 31:27S-28S. [PMID: 10330966 DOI: 10.1016/s0041-1345(99)00100-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- S J Knechtle
- Department of Surgery, University of Wisconsin Medical School, Madison, USA
| | | | | | | | | | | | | |
Collapse
|
30
|
Hamawy MM, Tsuchida M, Fechner JH, Manthei E, Knechtle SJ. Involvement of protein tyrosine phosphorylation in immunotoxin effects on T lymphocytes. Transplant Proc 1999; 31:785. [PMID: 10083335 DOI: 10.1016/s0041-1345(98)01766-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M M Hamawy
- Department of Surgery, University of Wisconsin, Madison, USA.
| | | | | | | | | |
Collapse
|
31
|
Abstract
In the second half of the 20th century, the transplantation of replacement organs and tissues to cure disease has become a clinical reality. Success has been achieved as a direct result of progress in understanding the cellular and molecular biology of the immune system. This understanding has led to the development of immunosuppressive pharmaceuticals that are part of nearly every transplantation procedure. All such drugs are toxic to some degree, however, and their chronic use, mandatory in transplantation, predisposes the patient to the development of infection and cancer. In addition, many of them may have deleterious long-term effects on the function of grafts. New immunosuppressive agents are constantly under development, but organ transplantation remains a therapy that requires patients to choose between the risks of their primary illness and its treatment on the one hand, and the risks of life-long systemic immunosuppression on the other. Alternatives to immunosuppression include modulation of donor grafts to reduce immunogenicity, removal of passenger leukocytes, transplantation into immunologically privileged sites like the testis or thymus, encapsulation of tissue, and the induction of a state of immunologic tolerance. It is the last of these alternatives that has, perhaps, the most promise and most generic applicability as a future therapy. Recent reports documenting long-term graft survival in the absence of immunosuppression suggest that tolerance-based therapies may soon become a clinical reality. Of particular interest to our laboratory are transplantation strategies that focus on the induction of donor-specific T-cell unresponsiveness. The basic biology, protocols, experimental outcomes, and clinical implications of tolerance-based transplantation are the focus of this review.
Collapse
Affiliation(s)
- A A Rossini
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | | | | |
Collapse
|
32
|
Abstract
Organ transplants in nonhuman primates provide a model which closely simulates the biological conditions of human organ transplantation, due to similarities between human and primate MHC (class I and II) structure and expression. Several strategies for tolerance induction have been developed in nonhuman primate models. These include targeting the T cell receptor or costimulatory molecules and the generation of mixed chimerism. Tolerance can be reliably induced in several such models, although none with 100% success.
Collapse
Affiliation(s)
- M M Hamawy
- Department of Surgery, University of Wisconsin-Madison Medical School, H4/784 Clinical Science Center, 600 Highland Avenue, Madison, WI 53792,USA.
| | | |
Collapse
|
33
|
Knechtle SJ, Fechner JH, Stavrou S, Neville DM, Dong Y, Hong X, Tsuchida M, Hamawy MM. Reversal of acute allograft rejection using immunotoxin. Transplant Proc 1998; 30:2150-1. [PMID: 9723422 DOI: 10.1016/s0041-1345(98)00569-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- S J Knechtle
- Department of Surgery, University of Wisconsin, Madison, USA
| | | | | | | | | | | | | | | |
Collapse
|
34
|
|
35
|
Affiliation(s)
- P J Morris
- Nuffield Department of Surgery, University of Oxford, John Radcliffe Hospital, UK
| |
Collapse
|
36
|
Armstrong N, Buckley P, Oberley T, Fechner J, Dong Y, Hong X, Kirk A, Neville D, Knechtle S. Analysis of primate renal allografts after T-cell depletion with anti-CD3-CRM9. Transplantation 1998; 66:5-13. [PMID: 9679815 DOI: 10.1097/00007890-199807150-00002] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND FN18-CRM9 is a CD3-specific immunotoxin that is capable of depleting CD3+ T cells. Pretreatment of rhesus monkeys with this agent before transplantation can induce donor-specific tolerance and "split tolerance" to renal allografts. METHODS Heterotopic renal transplants were performed on monkeys that received posttransplant FN18-CRM9. Histological and immunohistological staining, as well as analysis of the intragraft cytokine profile by reverse transcriptase polymerase chain reaction, was performed on percutaneous allograft biopsies. RESULTS Experimental monkeys had significant prolongation of allograft survival. Although an interstitial, mononuclear cell infiltrate was seen in all of the renal transplants, there was minimal evidence of acute cellular rejection. Histological evidence of alloantibody-mediated damage was detected 3 to 5 months after transplantation in the monkeys treated with FN18-CRM9. Immunohistology demonstrated the reappearance of CD3+ and CD4+ T cells, as well as CD20+ B cells, in the grafts. Cytokine analysis demonstrated expression of interferon-gamma. An intact anti-donor IgG response was seen. CONCLUSION Treatment of monkeys with FN18-CRM9 immediately after transplantation significantly prolongs renal allograft survival. Allograft biopsies demonstrate a lack of acute cellular rejection; however, alloantibody-mediated graft damage and rejection occur, with an intact anti-donor IgG response. The intragraft expression of the interferon-gamma may reflect this ongoing humoral rejection. These data suggest that even a brief period of T-cell allosensitization may lead to humorally mediated allograft damage. Efforts to achieve tolerance with posttransplant FN18-CRM9 will require modification of the protocol to deplete T cells before allosensitization exposure or to supplement the posttransplant immunomodification strategy.
Collapse
Affiliation(s)
- N Armstrong
- Department of Surgery, University of Wisconsin, Madison 53792, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Affiliation(s)
- P F Halloran
- Department of Medicine, University of Alberta, Edmonton, Canada.
| | | |
Collapse
|
38
|
Meng G, Jiang Y, Hubbard W, Thomas JM. The effect of anti-CD3-immunotoxin on T lymphocyte function in vitro. Transpl Immunol 1998; 6:53-9. [PMID: 9640629 DOI: 10.1016/s0966-3274(98)80035-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent advances in the design of immunotoxins (IT) have yielded significant improvements. FN18-CRM9, a construct of anti-CD3 epsilon mAb FN18 and mutated diphtheria toxin CRM9 has exhibited high specificity, low systemic toxicity and unusual efficacy compared to previous iterations of immunotoxins. Others and we have examined this anti-CD3-IT for the purpose of inducing immunological tolerance through selective ablation of T cells in rhesus macaques and have obtained encouraging results. In order to characterize its mode of action, we have examined its effects on peripheral blood and lymph node T cell killing in vitro. We have studied the cytotoxic mechanism induced by this anti-CD3-IT as well as its effects on proliferation, phenotypic changes and cytokine production (IL2, IFN gamma and TNF alpha). The results indicate that anti-CD3-IT was highly specific for T cell killing at doses as low as 1 x 10(6) micrograms/ml and showed a maximal effect at 48 h after exposure. The toxicity was restricted to T cells, as B cells and other bystander cells were spared. This immunotoxin was shown to induce T cell apoptosis, as assessed by TUNEL assay, DNA content and cytotoxicity. Fas expression was upregulated on T cells within 24 h after in vitro exposure to anti-CD3-IT, suggesting an early T cell activation phase prior to T cell death. T cell killing was manifest as an early cell cycle arrest at the G1/S phase transition, which appeared to virtually eliminate the production of cytokines. These findings corroborate the temporal, specificity and quantitative patterns for anti-CD3 immunotoxin administration previously observed in vivo.
Collapse
Affiliation(s)
- G Meng
- University of Alabama at Birmingham, USA
| | | | | | | |
Collapse
|
39
|
Chatenoud L. Tolerogenic antibodies and fusion proteins to prevent graft rejection and treat autoimmunity. MOLECULAR MEDICINE TODAY 1998; 4:25-30. [PMID: 9494967 DOI: 10.1016/s1357-4310(97)80542-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The immune mechanisms underlying autoimmune diseases and allograft rejection are similar, and T cells play a major role in both processes. Current therapeutic strategies rely on the application of nonspecific immunosuppression using chemicals such as corticosteroids, azathioprine, methotrexate, cyclophosphamide and cyclosporin. One major drawback of these drugs is their relative ineffectiveness over the long term; withdrawal leads to recurrence of the disease, but chronic administration puts patients at risk of being overimmunosuppressed, which can result in an increased incidence of infections and tumors. This review describes the advantages of developing biological agents that target immune receptors on T cells. In some cases, these agents can induce a state of durable, antigen-specific unresponsiveness in the absence of generalized immunosuppression, which could be useful in transplantation and autoimmunity.
Collapse
|