[The effect of perioperative portal venous inoculation with donor lymphocytes in combination with immunosuppressive agents on rat cardiac allograft survivals].

The synergistic effects of inoculation with donor lymphocytes via portal vein (PV) in combination with FK506 or monoclonal anti-T lymphocyte antibody (OX19) on cardiac allograft survival were investigated in rat heart transplant model (Lewis engrafted BN heart). The recipients were divided into the six groups. A) Control B) FK506 group C) PV group D) FK506+PV group E) OX19 group F) OX19+PV group. The recipients of PV group and FK506 group displayed a prolongation of cardiac allograft survival [MST: 11.2 +/- 1.0 and 12.4 +/- 1.0 days] compared with control group [MST: 7.3 +/- 0.3 days]. However, MST of FK506+PV group was 10.6 +/- 0.8 days, showing no synergistic effect of FK506 with PV administration. Significant prolongation of the graft survivals was not observed between OX19 group and OX19+PV group [MST: 17.2 +/- 2.1 and 15.0 +/- 1.2 days]. Serum from PV-treated hosts on day 7 after transplantation had suppressor effect (92.7%) on the MLR of Lewis responder cells toward donor BN cells. On the other hand, suppressor effect of serum from FK506+PV group was significantly reduced (5.8%) compared with PV alone. These results indicate that FK506 might inhibit the generation of suppressor factor which was induced in the serum after administration of donor lymphocytes, and that generation of suppressor factor might be dependent on T cell.