title: Synergistic immunosuppressive actions of cyclosporine with a mouse anti-rat alpha/beta-T cell receptor monoclonal antibody.
abstract: A mouse IgG1 mAb (R73) directed against the rat alpha/beta-TCR was documented not only to prolong the survival of allografts across major RT1 plus non-RT1 antigenic disparities, but also to display a synergistic immunosuppressive interaction with CsA. Heterotopic cardiac transplants from Buffalo (RT1b) rats survived significantly longer in Wistar-Furth (RT1u) hosts treated immediately after the operation with 0.25 mg/kg R73 i.v., with a mean survival time of 11.0 +/- 5.5 versus 6.8 +/- 1.2 days in the untreated group (P < 0.01). Administration of 0.5 or 5.0 mg/kg R73 displayed dose-dependent prolongation of survival to 17.0 +/- 8.3 days (P < 0.05) or 28.6 +/- 14.0 days (P < 0.01), respectively. One 0.5 mg/kg i.v. dose of R73 delivered to normal Wistar-Furth hosts produced peripheral T cell depletion that reversed after 16 days. Three injections of 0.5 mg/kg R73 on days 0, 2, and 4 prolonged allograft survival to 52.5 +/- 38.6 days compared with 17.0 +/- 8.3 days with a single dose (P < 0.01). Addition of 3 daily doses of 5 or 10 mg/kg CsA administered per oral gavage to a single dose of 0.05, 0.25, or 0.5 mg/kg R73 injected on day 0 produced a synergistic effect to prolong allograft survival, as determined by the rigorous median-effect analysis. The synergistic interaction, which may be explained by the inhibitory effect of CsA on Ca(2+)-dependent pathways triggered after activation of TCR, the target of R73, warrants clinical investigation in order to assess the potential impact of anti-alpha/beta-TCR mAb on CsA-based immunosuppressive regimens.
authors.affiliation: Department of Surgery, University of Texas Medical School at Houston, Texas 77030.
authors.forename: R J
authors.initials: RJ
authors.lastname: Knight
authors.forename: R
authors.initials: R
authors.lastname: Kurrle
authors.forename: S
authors.initials: S
authors.lastname: Stepkowski
authors.forename: F
authors.initials: F
authors.lastname: Serino
authors.forename: T C
authors.initials: TC
authors.lastname: Chou
authors.forename: B D
authors.initials: BD
authors.lastname: Kahan
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000627:therapeutic use*; D016572:Cyclosporine / Q000008:administration & dosage / Q000627:therapeutic use*; D006085:Graft Survival; D016027:Heart Transplantation; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D011915:Rats, Inbred BUF; D011920:Rats, Inbred WF; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D007166:Immunosuppressive Agents; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016572:Cyclosporine