Influence of a rat kidney perfusion using the anti-MHC class II monoclonal antibody and reduced dose of 15-deoxyspergualine on the allogeneic graft survival.

One of the main factors inducing rejection of the allogenic graft are the donor MHC-class II antigens. In this study, the allogenic rat renal graft survival after the blockage of MHC-class II positive cells was analyzed and compared with the effectiveness of the recipient treatment with 15-deoxyspergualine (15-DOS). It was found that the DA (RT1 a) rat kidney perfusion with the anti-MHC class II monoclonal antibody (MoAb 29A1--Kiel) allowed to prolong survival of the graft in the LEW (RT1 1) recipient (9.6 +/- 0.8 vs. 7.7 +/- 0.5 days). Our another study demonstrated that the 14 day treatment of the LEW recipient with 15-DOS at the dose of 0.5 mg/kg body weight can induce tolerance to the grafted kidney from the DA strain. The dose of 0.2 mg/kg body weight of 15-DOS prolonged the graft survival only to a small extend (16.5 +/- 0.5 days). In contrast, the combination of the graft pretreatment with MoAb 29A1 with the application of the reduced dose of 15-DOS to the LEW recipient allowed to further prolong the graft survival (97.4 +/- 59.0 days, n = 5). In 3 cases, the long-time (close to 150 days) graft survival was obtained. The above presented results suggest that the blockade of the MHC-class II antigens can reduce the immunogenicity of the graft. Although this procedure was not sufficient to induce tolerance, it allowed to minimize the immunosuppressive treatment.