The effect of antidonor serum and antigen-antibody complexes on the survival of heart allografts in rats presensitized with donor blood.

Preimmunization of BN recipients with 1 ml of WAG/Rij blood 7 days before grafting led to accelerated rejection of WAG/Rij hearts in 5 days (normal, 8 to 9 days) and of (WAG/Rij X BN)F1 hearts in 7 to 11 days (normal, 9 to 11 days). Preimmunization with mixtures of 1 ml of WAG/Rij blood and 0.25 ml of BN anti-WAG/Rij serum (antidonor serum) prevented the accelerated rejection in the WAG/Rij to BN combination and even led to prolonged graft survival. However, using the (WAG/Rij X BN)F1 as donor, this pretreatment led to accelerated rejection as well as prolonged graft survival. Preimmunization of BN recipients with 1 ml of WAG/Rij blood and antigen-antibody (Ag-Ab) complexes gave more consistent results; WAG/Rij hearts were normally rejected, whereas (WAG/Rij X BN)F1 grafts survived for 13 to 16 days. Treatment of preimmunized BN rats with antidonor serum or Ag-Ab complexes after grafting did not abolish the effect of sensitization in the WAG/Rij leads to BN combination. In the (WAG/Rij X BN)F1 to BN combination, these treatments resulted in graft survival times of 4 to 13 and 11 to greater than 50 days, respectively. In most experimental groups, Ag-Ab complexes were more potent as an immunoregulatory agent than was antidonor serum.