title: Donor-specific tolerance in fully major histocompatibility major histocompatibility complex-mismatched limb allograft transplants under an anti-alphabeta T-cell receptor monoclonal antibody and cyclosporine A protocol.
abstract: BACKGROUND
  Recent studies have demonstrated that treatment with alphabeta-T-cell receptor (TCR) monoclonal antibody and cyclosporine A (CsA) can extend survival in composite tissue allografts (CTA). The purpose of this study was to induce tolerance in fully major histocompatibility complex (MHC)-mismatched rat limb allografts under 7 days of a combined alphabeta-TCR-CsA protocol.
  
  
  METHODS
  The authors performed 30 hind-limb allotransplantations across the MHC barrier between Brown Norway donors (BN; RT1n) and Lewis recipients (LEW; RT1l). Isograft and allograft controls received no treatment. The experimental groups received monotherapy of alphabeta-TCR and CsA or a combination of alphabeta-TCR and CsA for 7 days only. Donor-specific tolerance and immunocompetence were determined by standard skin grafting in vivo and mixed lymphocyte reaction (MLR) in vitro. The efficacy of immunosuppressive therapy and the level of donor-specific chimerism were determined by flow cytometry.
  
  
  RESULTS
  Long-term survival (>350 days) was achieved in allograft recipients (n=6) under the 7-day protocol of combined alphabeta-TCR-CsA. Donor-specific tolerance and immunocompetence of long-term chimeras were confirmed by acceptance of skin grafts from the donors and rejection of the third-party alloantigens (AxC Irish). At day 120, MLR demonstrated unresponsiveness to the host and donor antigens but strong reactivity against third-party alloantigens. Flow cytometry confirmed the high efficacy of immunosuppressive treatment and the development of donor-specific chimerism (7.6% of CD4+-RT1n+ cells, 1.3% of CD8+-RT1n+ cells, and 16.5% of CD45RA+-RT1n+ cells) in the periphery of tolerated recipients.
  
  
  CONCLUSIONS
  Combined therapy of alphabeta-TCR-CsA for 7 days resulted in tolerance induction in fully MHC-mismatched rat hind-limb allografts. Tolerance was directly associated with stable, donor-specific chimerism.
authors.affiliation: Department of Plastic Surgery, Cleveland Clinic Foundation, A60, 9500 Euclid Avenue, Cleveland, OH 44195, USA. siemiom@ccf.org
authors.forename: Maria Z
authors.initials: MZ
authors.lastname: Siemionow
authors.forename: Dariusz M
authors.initials: DM
authors.lastname: Izycki
authors.forename: Maciej
authors.initials: M
authors.lastname: Zielinski
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D016572:Cyclosporine / Q000627:therapeutic use*; D005434:Flow Cytometry; D006085:Graft Survival / Q000187:drug effects / Q000276:immunology*; D006614:Hindlimb / Q000637:transplantation*; D006650:Histocompatibility Testing; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008212:Lymphocyte Depletion; D008285:Major Histocompatibility Complex; D023421:Models, Animal; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D013997:Time Factors; D014184:Transplantation, Homologous / Q000276:immunology* / Q000473:pathology
chemical_list: D000911:Antibodies, Monoclonal; D007166:Immunosuppressive Agents; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016572:Cyclosporine