The immunosuppressive effect of hepatocytes in rats--assessment by heart allograft survival and delayed-type-hypersensitivity reactions.

The immunosuppressive effect of hepatocytes was examined experimentally by heart allograft and delayed-type-hypersensitivity (DTH) reactions. The hepatocyte inoculation (1 X 10(7) of BDE (of the major histocompatibility complex haplotype RT1u), LEW (RT1l), and DA (RT1a) into the spleens of LEW rats significantly prolonged the survival of BDE heart allografts to 14.3 +/- 2.7 (mean +/- SD), 9.2 +/- 0.8, and 10.8 +/- 2.3 days respectively, compared with 6.7 +/- 0.8 days in controls (p less than 0.01). Moreover, the BDE hepatocytes had a significantly prolonged survival compared to the LEW (p less than 0.01) and DA (0.02 less than p less than 0.05) groups. BDE hepatocyte (donor specific) inoculation 4 and 7 days before priming with the spleen cells reduced DTH responses in the LEW rats to 44.6 +/- 4.8 per cent, and 74.2 +/- 8.0 per cent, respectively. DA hepatocyte inoculation (third party) 4 and 7 days prior to priming reduced DTH responses to 72.5 +/- 11.5 per cent, and 76.5 +/- 11.9 per cent, respectively. All DTH responses were significantly suppressed after hepatocyte inoculation compared to 100 per cent in the controls (p less than 0.01). Moreover, the inoculation of BDE hepatocytes (donor specific) 4 days prior to the priming significantly reduced DTH responses compared to the group primed 7 days before (p less than 0.01). From these results we concluded that hepatocytes produced not only non-specific but also donor specific immunosuppressive effects through T cell immune reaction. Moreover, donor specific immunosuppressive effects were induced at least 4 to 7 days after hepatocyte inoculation.