title: Mechanisms of targeting CD28 by a signaling monoclonal antibody in acute and chronic allograft rejection.
abstract: There is increasing evidence that ongoing T-cell recognition of alloantigen and activation are key mediators of chronic allograft rejection. The CD28-B7 pathway is unique among costimulatory pathways in that two alternate ligands for B7 exist: CD28 and CTLA4. Recently, it has been suggested that CTLA4 negative signaling may be required for induction of acquired tolerance in vivo. A strategy by which the T cell is targeted at the CD28 receptor rather than its ligands would theoretically allow the inhibitory functions of the CTLA4-B7-1/2 axis to remain intact. Using a rat-specific monoclonal antibody, we investigated the effect of targeting CD28 in a model of chronic rejection without the confounding variable of immunosuppression. We also used an acute cardiac allograft rejection model to investigate CD28 stimulation-based strategies to induce donor-specific tolerance. We demonstrated that anti-CD28 monoclonal antibody was as effective as CTLA4 immunoglobulin in protecting against chronic allograft vasculopathy. In addition, a short course of cyclosporine therapy synergized with either anti-CD28 monoclonal antibody or CTLA4 immunoglobulin, suggesting that it may be clinically relevant to combine low-dose calcineurin inhibitors with CTLA4 immunoglobulin or anti-B7 antibodies. Finally, we report on the potential mechanisms of action of targeting CD28 in vivo.
authors: Laboratory of Immunogenetics and Transplantation, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors: Victor M
authors: VM
authors: Dong
authors: Xueli
authors: X
authors: Yuan
authors: Ana J
authors: AJ
authors: Coito
authors: Ana Maria
authors: AM
authors: Waaga
authors: Mohamed H
authors: MH
authors: Sayegh
authors: Anil
authors: A
authors: Chandraker
mesh_terms: D000069594:Abatacept; D000208:Acute Disease; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology; D018106:CD28 Antigens / Q000276:immunology*; D060908:CTLA-4 Antigen; D002908:Chronic Disease; D003433:Crosses, Genetic; D005260:Female; D006084:Graft Rejection / Q000276:immunology*; D016027:Heart Transplantation / Q000276:immunology*; D018796:Immunoconjugates; D007519:Isoantigens / Q000276:immunology; D008297:Male; D018448:Models, Immunological; D051381:Rats; D011917:Rats, Inbred Lew; D011920:Rats, Inbred WF; D013601:T-Lymphocytes / Q000276:immunology; D014184:Transplantation, Homologous
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D018106:CD28 Antigens; D060908:CTLA-4 Antigen; C556708:Ctla4 protein, rat; D018796:Immunoconjugates; D007519:Isoantigens; D000069594:Abatacept